CA2033217A1

CA2033217A1 - Use of two or more nested apertured endless belts with inverted arch bottom flights and generally horizontal top flights to recover bitumen and minerals

Info

Publication number: CA2033217A1
Application number: CA002033217A
Authority: CA
Inventors: Jan Kruyer
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-12-27
Filing date: 1990-12-27
Publication date: 1992-06-28

Abstract

USE OF TWO OR MORE NESTED APERTURED ENDLESS BELTS WITH
INVERTED ARCH BOTTOM FLIGHTS AND GENERALLY HORIZONTAL TOP
FLIGHTS TO RECOVER BITUMEN AND MINERALS

ABSTRACT

A process and apparatus for the recovery of bitumen and bitumen wetted minerals from separating mixtures of bitumen, bitumen wetted minerals, water and water wetted minerals using two or more nested apertured endless belts on conveyor supports that support these belts to form top flights approaching generally horizontal paths above separating mixture and bottom flights in the form of or approaching inverted arches immersed in separating mixtures.
Bitumen separates from a mixture, is captured by and adheres to belt surfaces as the mixtures passes through bottom flight apertures, and is conveyed to corresponding top flights where it falls off into receptacles and/or is washed off with water. Mixture that has passed through apertures of the bottom flight of a first belt may be passed through apertures of the bottom flight of a second belt, nested with the first belt, for additional bitumen capture, or is removed. Bitumen washed off with water from the top flights of a first and/or a second belt is removed for further processing or is passed to an inside enclosure that contains a third belt, nested with the first and/or second belts of the invention, to yield a final bitumen product that is low in hydrophilic minerals. Alternately, mixture may be introduced into the volume between the bottom flights of two nested belts and flow through the apertures of both bottom flights simultaneously.

Description

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USE OF TWO OR MORE NESTED APERTURED ENDLESS BELTS WITH
INVERTED ARCH BOTTOM FLIGHTS AND GENERALLY HORIZONTAL TOP
FLIGHTS TO RECOVER BITVMEN AND MINERALS

BACKGROUND O~ THE _NVENTION
The present invention relates to the recovery of bitu-men and bitumen wet~ed oleophilic minerals from a mixture of bitumen, water, bitumen wetted oleophilic minerals and water wetted hydrophilic minerals.
This invention is primarily concerned with the recovery of bitumen and bitumen wetted minerals from mined oil sands, from tailings of mined oil sands plants, from tailings pond sludge of mined oil sands plants, from bitumen or heavy oil, water and minerals mixtures of oil wells, from bitumen and water mixed with ore of mineral mines and from bit~men and water mixed with materials of placer deposits.
Extensive deposits of oil sands, which are also known as tar sands or bituminous sands, are found in Northern Alberta Canada and in many other parts of the world includ-ing the USA, Venezuela, and in various countries of Africa and Asia, including the USSR.
The oil sands ore of interest in the present invention are composed of non-consolidated siliceous material with grains generally having a size greater than that passing a 325 mesh screen (44 microns) and a relatively heavy viscous petroleum called bitumen, which at least partly fills the -voids between the grains in quantities from 4 to 25 percent of total composition. (All percentages referred herein are in weight percent unless noted otherwise) Generally the bitumen content of oil sand ore that is currently mined commercially is between 8 and 15 percent.
This bitumen contains typically 4.5 percent sulphur and 38 percent aromatics. Its specific gravity at 15 deyrees C.
ranges generally from about 1.0 to about 1.1. The oil sands also contain clay and silt. Silt is defined as siliceous material which will pass a 325 mesh screen, but which is ~,32~ ~

larger than 2 microns. Clay is material smaller than 2 mi-crons, including some siliceous material of that size. In some cases the oil sands also contain a small percentage of heavy minerals including ilmenite, rutile, zircon and other metallic minerals.
Much of the world resource of bitumen and heavy oil is deeply buried by overburden. For example it has been esti-mated that less than lO percent of the Alberta oil sand de-posit is close enough to the earth's surface to be conve-niently recovered by current surface mining methods. Theremainder is buried too deeply to be economically strip mined. Hydraulic mining has been proposed for those de-posits. However, with current technology, it is considered that enhanced recovery by steam injection, by injection of aqueous solutions, or by in-situ combustion may possibly be more effective for obtaining bitumen from deeply buried formations." Such enhanced recovery methods use one or more oil wells that penetrate the formation and stimulate the flow of bitumen or heavy oil to a recovery well. In some cases, the same well may be used to stimulate and recover the resource. Depending upon the procedure employed, en-hanced recovery methods generally produce mixtures of water, bitumen and some mineral particles, and these recover a lower percentage of the bitumen in place than mining meth-ods.
There are several well known procedures for separatingbitumen from mined oil sands. In a hot water process, such as disclosed in Canadian Patent No. 841,581 issued 12 May 1979 to Paul H. Floyd et al.; the bituminous sands are jet-ted with steam and mulled or tumbled with a minor amount ofhot water and sodium hydroxide in a conditioning drum to produce a pulp or slurry which passes from the conditioning drum through a screen, which removes debris, rocks and oversize lumps, to a sump where it is diluted with addi-tional water. It is hereafter carried into a separationcell. In the separation cell, sand settles to the bottom as primary tailings which are discarded. Bitumen rises to the %~33~

top of the cell in the form of a bituminous froth which is called the primary froth product. An aqueous middlings layer containing some mineral and bitumen is formed between these layers. A scavenging step is normally conducted on this middlings layer in a separate flotation zone. In this scavenging step the middlings are aerated so as to produce a secondary tailings product, which is discarded, and a sec-ondary froth product.
The secondary froth product is thereafter treated to remove some of its water and mineral matter content and is thereafter combined with the primary froth for further treatment. This combined froth typically contains about 52 percent bitumen, 6 percent minerals, 41 percent water, all by weight, and may contain from 20 to 70 volume percent air.
It resembles a liquid foam that is usually treated with steam to improve its flow characteristics for subsequent processing. The primary and secondary tailings products are usually combined and water may be added to enhance the pipeline hydraulic disposal of this combined tailings stream called the extraction tailings.
The high water and minerals contents of the combined froth product normally are reduced by diluting it with hy-drocarbon diluent such as naphtha. It is then centrifuged to produce a tailings product, called the centrifugal tail-ings, and a final bitumen product that typically containsessentially no water and less than 1.0 percent solids, from which the naphtha is recovered, and then is suitable for coking, hydrovisbreaking or other refining techniques to produce a synthetic crude oil. The centrifugal tailings, containing some naphtha, bitumen, silt, clay and heavy min-erals are discarded.
There are basically three effluent streams from the hot water process. Each carries with it some of the bitumen from the feed; thereby reducing the efficiency of the pro-cess. These include the oversize materials coming from thescreen, the extraction tailings and the centrifugal tail-ings. Approximately ten percent of the bitumen in the 2 ~ ?~ 3 ~ ~ 7 original feed and 2.5 percent of the naphtha stream may be lost in this manner. Much of this lost bitumen finds its way into large retention ponds or tailings ponds that are typical of the hot water process. The bottom of such re-tention ponds may contain from 20 to to 50 percent dispersed mineral matter consisting substantially of clay and silt as well as 2 percent or more bitumen by weight. As disclosed in Canadian Patent No. 975,697 issued on 7 October 1975 to David H. James this part of the pond contents, referred to as sludge, or tailings pond sludge, is a potential source of recoverable bitumen.
In the hot water process the oleophilic heavy minerals present in the oil sand ore, such as rutile, ilmenite and zircon and other oleophilic minerals, tend to be attracted to and wetted by the bitumen of the oil sands during pro-cessing, and these minerals are recovered in the combined bitumen froth product. The minerals are removed from this bitumen product in the dilution centrifuging step and are part of the centrifugal tailings of the hot water process.
I have fGund that the extraction tailings from the hot water process also contain oleophilic minerals. These oleophilic minerals are in association with and are wetted by the bitumen that is discarded with the extraction tail-ings. I have discovered that this residual bitumen gener-~5 ally contains a higher percentage of oleophilic minerals than the bitumen froth produced by the hot water process. I
have concluded that most of the bitumen that remains with the extraction tailings of the hot water process is there because this bitumen does not float as readily as the bitu~
men that is recovered. The increased amount of minerals associated with this bitumen make it denser and more diffi-cult to float than the bitumen that is normally recovered in the flotation steps of the hot water process. Then, when this residual bitumen is recovered from these extraction tailings by a process, such as in the present invention, which does not rely on flotation alone, the resulting bitu-men product will contain a large percentage of oleophilic 2a33~

minerals that may have a commercial value when the bitumen is removed in a subsequent process.
When Alberta oil sands are mixed with water and are separated with the present invention, the bitumen product contains heavy minerals which are bitumen wetted and the water phase contains sand, silt and clay that are water wetted. When extraction tailings from a hot water process are separated with the present invention to recover the residual bitumen, the bitumen product from that separation contains heavy minerals which are bitumen wetted and the water phase contains sand, silt and clay that are water wetted. Similarly, when tailings pond sludge is separated with the present invention, the bitumen product from that separation contains heavy minerals which are bitumen wetted and the water phase of the sludge contains silt and clay that are water wetted. In the present invention therefore, when a mixture is separated, the bitumen wetted minerals are recovered along with the bitumen phase and the water wetted minerals are discarded with the water phase. As more bitu-~0 men is recovered from such a mixture, more oleophilic miner-als are recovered from the mixture as well.
The present invention therefore serves to recover bitu-men but it also concentrates potentially valuable minerals from a mixture by capturing these with the bitumen product in the separation process. These minerals are released when the bitumen product is diluted and centrifuged, or when the bitumen is removed from these minerals in some other way.
This concentration process is a secondary benefit of the present invention that may make it possible to economically recover, as a by-product, useful minerals from mined oil sands, tailings or sludge, of oil sand ores that contain traces of useful minerals. Recovery of valuable minerals may in some cases be the primary objective of the present invention.
Heavy minerals are found in small concentration of about 1~ in the Alberta oil sands. Oil sands from other locations may contain traces of other types of minerals, in-2~33~ ~7 cluding gold, silver, platinum and other useful or precious minerals. These minerals in many cases are or become bitu-men wetted in the process of the present invention and are recovered with the bitumen product. These can be separated from that bitumen to yield a minerals by-product of the bi-tumen extraction process.
The present invention may also be used to recover use-ful minerals from other ores. Bitumen and water may be mixed with ore from a mine to cause the minerals of the ore to become bitumen wetted while the gangue becomes water wetted. In a subsequent separation by the present invention of this ore-bitumen-water mixture, the resulting bitumen product will contain bitumen wetted mineral of the ore for recovery, and the water effluent will contain water wetted gangue of the ore to be discarded. On other occasions bitu-men and, if required, water may`be mixed with a placer de-posit of minerals, metals or precious stones to~ cause these to become bitumen wetted and the gangue to remain water wetted. In subsequent separation, by the present invention of this placer deposit mixture, the resulting bitumen prod-uct will contain bitumen wetted minerals, metals or precious stones of the placer deposit for recovery, and the water effluent will contain water wetted gangue of the placer de-posit for disposal. The useful minerals, metals or stones ~5 are subsequently recovered by removing the bitumen and the residue separated into components by mineralogical methods.
The mineral recovery aspects of the present invention may in time compete with conventional minerals froth flotation, with the added advantage that mineral particles of larger size may be recovered more efficiently than with flotation.
The present invention has a number of similarities with Canadian patent application Serial No. 601,164 which was filed by the same inventor on May 30, 1989. However this prior art only used one belt in each separator whereas the present invention uses two or more nested belts in one sepa-rator to achieve significant improvements in process per-formance with respect to increased throughput of separating 2~ 2~

mixture through the separator, with respect to improved per-centage recovery of bitumen and oleophilic minerals from the separating mixture and/or with respect to improvemen~ in the quality of the bitumen product produced from the separating mixture.
The present invention also has a number of similarities with prior art of Canadian Patent No. 1,129,363 granted to the same inventor on 10 August 1982 where the belt flights, supported by two conveyor end rollers were generally straight and were both inclined at about the same slope, whether immersed or not, and required extrusion oE bitumen through the belt top flight apertures to achieve removal from the top flight. In this prior art, either high extru-sion forces were necessary to recover cold bitumen from the belt when the process was operated cold or bitumen fell off the belt, back into the separating mixture, when the process was operated warm, which has limited the operating options of the prior art.
The present invention has overcome many of the draw-backs of the prior art.

BRIEF DESCRIPTION OF THE_VENTION

The present invention relates to the recovery of a bi-~5 tumen and bitumen wetted minerals product from a mixture of bitumen, waterl water wetted minerals and bitumen wetted minerals with the use of two or more apertured nested end-less belts.

In one aspect, the invention provides a method for the recovery in one apparatus of bitumen and bitumen wetted minerals from one or more mixture(s) of bitumen, water, bitumen wetted minerals and water wetted minerals which method comprises passing through said mixture(s) two or more nested apertured endless belts each belt consisting of a bottom flight at least partly immersed in one of said one or more mixture(s) and a top flight that is not immersed in bitumen, minerals and water mixture, a) wherein bitumen, including some water and some minerals, separates from bitumen, minerals and water mixture and attaches to belt bottom flight surfaces as mixture passes through belt bottom flight apertures causing mixture to become bitumen depleted after which bitumen depleted mixture is removed from said apparatus to disposal or is recirculated or reused, b) wherein bel~ bottom flight surfaces, with bitumen adhering to these surfaces, emerge from mixture, move upward and revolve to become temporarily top flight surfaces, c) wherein bitumen, including some water and some minerals, falls from said top flight surfaces for further processing into a compartment or into a receiver located under said top flight surfaces after which said surfaces revolve to become temporarily bottom flight surfaces, d) wherein said belts are supported by at least two conveyor supports, at least one of which is revolving and is ~0 driven, the top of each support being located above the surface of at least one of said mixture(s), in such manner that each top flight between its supports assumes or approximates a generally horizontal path and each bottom flight between its supports assumes a path that resembles or 5 approximates an inverted arch, e) wherein end walls are provided along each bottom flight adjacent to both immersed edges, f) wherein at least the bottom flights of said nested belts are enclosed in one or more tank(s) or compartment(s) 0 that contain(s) said mixture~s) for separation.

In another aspect the invention provides an apparatus for the separation of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals.
and water wetted minerals, which apparatus comprises:

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a) at least one container for containing a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, b) conveyor supports to mount two or more nested movable apertured oleophilic endless belts supported in such a manner that in operation their paths include top flights that are approximately horizontal and are above the normal level of mixture in said container, and bottom flights that hang in the shape of or approximate the shape of inverted arches , and that extend down to below the said normal level of mixture so that a portion of each bottom flight is immersed in bitumen, water and minerals mixture during operation of the apparatus, whereby in operation bitumen, including some water and minerals, adheres to bottom flight surfaces of said apertured belts as mixture passes through bottom flight apertures, c) means to revolve and drive one or more of said conveyor support(s) whereby in operation said endless belts are revolved and bottom flight belt surfaces and adhering bitumen rise from said mixture and are conveyed temporarily to corresponding top flights.

In preferred embodiments of the present invention the mixture is separated with two or more nested apertured oleophilic endless moving belts of novel design, each con-sisting of a top flight that is generally horizontal, and a bottom flight that is in, or approximates to, the form of an inverted arch. The endless belts are preferably supported by at least two shafts or rollers, that preferably keep each top flight under tension, while each bottom flights are al-lowed to hang down from these shafts or rollers in the form of an inverted arch. Each bottom flight is part of a sepa-ration zone and passes through and is at least partly im-mersed in the mixture it is separating while the top flights are not immersed. Mixture in the separation zone or zones is passed to the apertured oleophilic endless belt bottom flights such that bitumen and bitumen wetted minerals of the s~

mixture adhere to the belt surfaces as water and water wet-ted minerals of the mixture pass through the belt apertures.
In some preferred embodiments, mixture is passed through two or more belts in sequence or simultaneously to recover more bitumen from a mixture than is recovered with only one belt of the prior art, or to achieve higher mixture throughputs at approximately the same percentage bitumen recovery.
In these preferred embodiments, the flow of mixture through the bottom flight belt apertures preferably is from the inside of each inverted arch to the outside of that arch. This is accomplished by introducing the mixture for separation into the inside of each inverted arch and by withdrawing mixture from the outside of each arch after the mixture has passed through the belt apertures. The flow of mixture may also be from the outside of each inverted arch to the inside of each inverted arch. This is accomplished by introducing to or allowing mixture to flow to each belt from the outside of each inverted arch for separation and withdrawing mixture from the inside of each inverted arch after it has passed through the belt apertures.
In at least one case described in these specifications of the invention the flow of mixture through belt apertures is simultaneously in both directions, when mixture is intro-duced for separation between the inverted arches of two nested belts. In this case, a portion of the separating mixture flows through belt apertures towards the inside of the inverted arch of one belt while the other portion of the separating mixture flows through belt apertures towards the outside of the inverted arch of the other belt. Using two nested belts in this manner results in higher mixture throughput at approximately the same percentage bitumen re-covery in one apparatus as compared with the one belt of the prior art.
In at least once case described in these specifications the mixture flows through the apertures of the inverted arches of at least two nested belts in sequence. In this case the mixture for separation is introduced into the in-side of the inverted arch of the inner of the two nestedbelts and is wi~hdrawn from the ou~side of the inverted arch of the outer of the two nested belts.
In another preferred embodiment the mixture for sepa-ration flows through two or more nested belts in separatecompartments to produce a bitumen product that is superior in quality than the bitumen product produced from one belt or produced from two belts in one compartment. In this preferred embodiment mixture flows through one or more nested belts to capture bi~umen and minerals from that mix-ture. This belt or these belts convey the captured bitumen and minerals to corresponding top flight or flights where jets of water wash off the bitumen and minerals to form an intermediate product which flows into a middle compartment where another nested belt or belts are used to capture bitu-men and oleophilic minerals from that intermediate product as water and hydrophilic minerals pass through belt aper-tures in that middle compartment. Using two nested belts in this manner allows for the recovery of bitumen from a mix-ture and then in the same apparatus allows for the removalof water and hydrophilic minerals from that bitumen to yield a final bitumen product in the invention lower in hy-drophilic minerals content than is possible from the same mixture with only one belt in the apparatus of the prior art.
In the context of this invention, nested belts refer to two or more parallel endless belts where one or more belts are mounted inside one or more other belts. Several belts may be supported on the same conveyor supports or each belt may be supported on its own separate conveyor supports. The belts may all be contained in one compartment or these may be contained in separate compartments that nest with each other.
The surfaces of the moving endless belts of the present invention are oleophilic and therefore capture bitumen and bitumen wetted minerals that separate from the mixture in the separation zones along the bottom flights as these bitu-men or bitumen wetted minerals come in contact with said surfaces, while water and water wetted minerals of the mix-ture continue to ~low through the belt apertures. These captured bitumen and bitumen wetted minerals , which may contain some water and hydrophilic minerals, are carried or conveyed by the belts from the bottom flights to the ~op flights. The top flights are part of the recovery zones where bitumen, and contained minerals and water, fall ofE
the belts into receivers. In some cases the bitumen and minerals are washed from the belt top flight or flights with water and are introduced into an inside compartment for passage through the apertures of one or more secondary belts which are nested with the primary separation belts. In stead of washing bitumen product from the top flights with water, bitumen product may also flow from the top flights by gravity only, with or without the help of additional heat , or may be blown off the top flight(s) with steam or hot air.
The resulting bitumen product is collected into receiver(s) mounted under said top flight(s).
As bitumen emerges from the interface on the bottom flights, fine mists of water from nozzles may be used to wash off superficial hydrophilic minerals from that bitumen to enhance the quality of the resulting bitumen product in the recovery zones.
DRAWINGS

The invention will be further illustrated with reference to the accompanying drawings showing, by way of example, embodiments of the invention in which:
Figures 1 and 2, in accordance with the invention, are schematic end views of a typical separator showing three nested apertured endless belts, complete with supports and tanks.
Figure 3 is a perspective view of a portion of the separator of Figure 2, showing an outside belt and an inside belt, complete with rollers, shafts and sprockets piping fixtures and bearing supports, but not showing all the com-ponents of Figure 2.
Figure 4 is a flow diagram of the water supply for the cold water nozzles and for the warm water noz~les of Figures 1 and 2.
Figures 5,6 and 7 are illustrations of the construction of various types of apertured belts.
Figure 8 is a perspective view of the preferred shape of a typical apertured belt of the invention using a belt construction as in Figure 5.
Figure 9 is a graph of the estimated amount of sludge accumulating in mined oil sands tailings ponds near Fort McMurray, Alberta, on an annual basis and of the estimated amount of bitumen that will be contained in that sludge.
Figure 10 is a historical graph of the estimated ulti-mate reserves of bitumen contained in the Alberta oil sands.
Figure 11 is a historical graph of percentage bitumen recovery from mined oil sands that has been achieved by Suncor, one of the mined oil sands plants, compared with average annual grade of oil sand mined over a ten year pe-riod.
Figure 12 is a perspective view of a portion only of the components of the separator of Figure 2, showing the outside tank and the inside tank of a separator especially designed for ease of maintenance and repair.
Figure 13 is a schematic drawing of one of the aper-tured endless belts supported by only two conveyor supports, showing the normal sag in the top flight when the belt is not moving and when the bottom flight is immersed.
Figure 14 is a schematic drawing of the top portion of the belt of Figure 13, but with a third conveyor support provided to reduce sag of the top flight.
Figure 15 is a schematic drawing of the top portion of the belt of Figure 13, but with a third and fourth conveyor support provided to further reduce sag of the top flight.
The third and fourth conveyor supports are rollers.

2 ~

Figure 16 is a schematic drawing as in Figure 15 with the exception that that third and fourth supports are sta-tionary belt guides as in Figures 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

For the purpose of the present invention, bitumen is broadly defined as a hydrocarbon that at the temperature of the separating mixture of the invention has a viscosity be-tween 1000 and 50,000,000 centipoises. It may include con-ventional oil sand bitumen, conventional heavy oil, tar, wax, asphalt, or any other thick or viscous petroleum or oil based fraction or product, as well as residues from land or marine oil spills.
Bitumen wetted minerals are defined for the purpose of the present invention as any number of mineral particles at least a portion of whose surface areas are oleophilic and covered with bitumen, or have become oleophilic and covered with bitumen due to exposure to bitumen and water. When the surface area portion covered by bitumen of a mineral parti-cle is large enough to cause adhesion of this particle on contact to bitumen on a mechanical surface, such as a belt, `
the mineral particle is considered to be bitumen wetted for the purpose of the present invention.
Water wetted minerals are defined for the purpose of the present invention as any number of mineral particles most of whose surface areas are hydrophilic and covered with water or have become hydrophilic and covered with water due to exposure to bitumen and water, which mineral particles have no bitumen on their surfaces, or the surface portions of the particle covered by bitumen are not large enough to cause these mineral particles to adhere to bitumen on a me-chanical surface on contact.
It is to be understood that the present invention is used to separate bitumen and bitumen wetted minerals from water and water wetted minerals, no matter from where these originate. A mixture for separating, that contains bitu-2 ~ ~J' .~ ~J ~ )~

men, water, bitumen wetted minerals and water wetted miner-als, may already exist in that Eorm; or it may be prepared as part of the separation objective prior to the actual separation in the present invention.
For example, mined oil sands tailings and tailings pond sludge are mixtures that normally contain bitumen, water, bitumen wetted minerals and water wetted minerals; and these may be separated in the form these are normally produced or normally exist or these may be diluted with additional water 10 before these are separated in the present invention. On the other hand, oil sands, as mined, normally contain only very small amounts of water or no water at all. Water needs to be added to and mulled with such oil sands to prepare a mixture or slurry suitable for separation by the present 15 invention. In some cases heat and/or mechanical energy needs to be added as well to the oil sands, along with the water; and this mixture needs to be tumbled and screened to digest the lumps of oil sands in water and to remove debris, rocks and oversize lumps before it can be separated by the 20 present invention. Furthermore, both water and bitumen may be added to mineral mine ores, and the resulting mixture tumbled, mixed, ground and screened before these ores are suitably separated into bitumen wetted minerals and water wetted gangue. In a similar way, bitumen and perhaps water ~5 may be added to placer deposits, tumbled and screened, and perhaps ground, before it is suitably separated into bitumen wetted minerals and water wetted gangue in the present in-vention.
Mixture for separation in the present invention may 30 also be bitumen froth or bitumen product from other pro-cesses with or without water added. In the case of the Hot Water process, the primary and secondary froth contain con-siderable amounts of water and hydrophilic minerals that may be removed by the process of the present invention. This 35 may be done by adding cold water to the warm froth and mix-ing it to disperse the hydrophilic minerals in the water phase. This then becomes the mixture for separation in the .

2~33~

process of the present invention. In the case of a Cold Water process, or in the case of other flotation processes that operate at a temperature colder than the Hot Water process, the bitumen product from these processes may con-tain considerable quantities of water, and hydrophilic min-erals, which may be removed from that bitumen in an appara-tus, such as in Figure 2.
I have discovered that when a mixture of bitumen, bitu-men wetted minerals, water and water wetted minerals is passed to an apertured oleophilic wall in a separation zone, the bitumen and bitumen wetted minerals separate from that mixture and attach to this wall, when these come in contact with it, as water and water wetted minerals of the mixture continue to pass through the wall apertures. When this wall is stationary, only a relatively small amount of bitumen and bitumen wetted minerals can be collected in this manner since the bitumen and bitumen wetted minerals accumulating on the wall surfaces will close the apertures and prevent further flow of mixture through the apertures. However, ~0 when the wall is moving, and bitumen and minerals are re-moved from the wali, more mixture can be separated in this manner without danger of closing the apertures.
Furthermore, when the wall is a continuously revolving end-less belt that has at least one zone for separation and at ~5 least one zone for removing the adhering bitumen and bitumen wetted minerals from the belt surfaces and out of the belt apertures, the process becomes continuous and large amounts of mixture may be separated per day or per year by the mov-ing belt on a continuous basis.
I have found that optimum separation is achieved by an apertured oleophilic belt if the separating mixture is evenly distributed over the whole belt area, and can flow uniformly and slowly to the belt surfaces and through the belt apertures at a temperature that is optimum for adhesion of bitumen to bitumen on the belt surfaces, and under condi-tions that allow the bitumen and bitumen wetted minerals to remain clinging to the belt surfaces until these surfaces 2 ~

reach the recovery zone. This optimum desirable temperature may vary with the type of mixture being separated, but it may be optimized in the process of the present invention for each mixture.
The mixture preferably has a temperature between zero degrees centigrade and eighty degrees centigrade, more preferably between zero degrees centigrade and fifty degrees centigrade. The viscosity of the bitumen in the separating mixture is preferably between 10,000 and 5,000,000 cen-tipoises, and more preferably between 100,000 and 2,000,00 centipoises.
Separation zone or zones of the present invention are along the bottom flight of one or more of the nested aper-tured oleophilic endless moving belts that hang in the form of, or approximate to, an inverted arch and are at least partly immersed in mixture under separation, while recovery zone or zones of the present invention along the generally horizontal top flight of these same one or more nested end-less belts. End walls are placed along the belt edges in the separation zone or zones of the invention to minimize flow of mixture past the belt edges and to cause mixture to flow through the belt apertures.
Bitumen and water have approximately the same specific gravity, but minerals are usually more than twice as dense as water. For many mixtures that are separated with the present invention the bitumen product contains some minerals and is lighter than, or is of about the same specific grav-ity as, the mixture being separated. Therefore, there are at least two reasons why immersing the bottom belt flights in separating mixture is beneficial. Compared with passing mixture for separation through an un-immersed belt, immers-ing the belt in the separating mixture helps to distribute the mixture on the belt surface and to slow down the flow of mixture through belt apertures and makes it easier for bitu men and bitumen wetted minerals of the mixture to be cap-tured by the belt surfaces. Immersing a belt in the sepa-rating mixture in a separation zone further facilitates bi-2 ~

tumen and bitumen wetted minerals captured by the belt sur-faces to stay with these surfaces until these belt surfaces emerge from the mixture.
Immersion of bottom flights in separating mixture gives the bitumen and the bitumen wetted minerals a buoyed density and reduces the effect of the force of gravity in a separa-tion zone. This makes it easier for bitumen and minerals to adhere to the belt surfaces and to remain adhering to these surfaces until conveyed out of a separation zone. Only in the un-immersed portion of a separation zone does the force of gravity have significant effect on the captured bitumen and bitumen wetted minerals to induce these to flow off the belt. However, in the present invention, the slope of the inverted arch of each bottom flight where it is not immersed is very steep and, instead of falling off a belt, the bitu-men and bitumen wetted minerals flow down the inverted arch under the force of gravity. When the velocity of a belt is kept higher than the velocity of bitumen and minerals flow-ing down the inverted arch of the un-immersed portion of that bottom flight, the net result is an upward conveyance of bitumen and minerals. from the separation zone into the recovery zone.
The present invention uses two or more nested belts in one apparatus. These belts may consist of of nested belts that use the same belt supports or may consist of nested belts that use different belt supports for each belt or for each set of several nested belts. It differs from the prior art which used only one belt in one apparatus. By combining more than one belt in one apparatus, more efficient use is made of the apparatus, which may result in in lower fabri-cation and operating costs.
In the case of Figures 1 and 2, where intermediate bi-tumen product is dispersed in warm water and processed imme-diately after recovery in the same apparatus, the present invention prevents intermediate product bitumen particles from agglomerating and prevents these bitumen particles from recapturing water and hydrophilic minerals prior to passage 2~332~ 7 through a third belt. When two separators in their own separate enclosures are used in stead, and the intermediate bitumen product pumped through a pipe between these two en-closures, some aggomeration of bitumen particles tends to take place. Such premature agglomeration is not beneficial for improving bitumen product quality and is reduced in the present invention by combining the process in one appartus.

FIGURE 1.
One preferred belt configuration of the pxesent invention is illustrated in Figure 1. Three belts are used, nested to form in one apparatus two stages of sludge or slurry separation in one enclosure and one stage of bitumen product clean up in a separate inside enclosure of the same apparatus. Each of the three belts (34, 44 and 45) has at least two supports to shape the belts into a top flight that is generally horizontal and a bottom flight that hangs down from its two main supports in the form of an inverted arch.
In the case of this Figure, the two separation belts (44 and 45) use the same belt supports and the clean up belt (53) uses a separate set of belt supports. Mixture for separa-tion, for example, sludge, oil sand tailings or slurry, flows into the separator tank (41) through an inlet (40) into the inside of the inverted arch of the middle belt (44). All three belts are moving by means of driven shafts (11 and 21) and sprockets (12 and 25) which engage with the apertures (96 and 97) of the middle (44) and inside (34) belts. The top flight (5) of the outside belt (45) rests on the top flight (6) of the middle belt (44) and moves due to friction and drag between these two top flights. Additional supports (103) are provided along the top flights of the middle (44) and of the inside (34) belts (not shown) to keep the top flight approximating a straight and horizontal flight. These extra supports are illustrated in Figures 13 to 16 and are explained in the description of those Figures.
Location of the sprockets (12 and 25) on the shafts (11 and 21) that drive the belts are shown in Figure 3. The mixture 2 ~

(93) for separation that has been introduced from the inlet (40) flows through the belt apertures (96 and 97) and fills the tank (41) to the interface (13 and 14) that is main-tained by controlling the outflow of mixture (95) through a bottom outlet (42) and/or by gravity overflow through the side outlet (101). Mixture for separation (93) that occu-pies the volume contained by the end walls (99 and 100 shown in Figure 3) within the inverted arch of the middle belt (44) flows outward through the belt apertures (96) to occupy the volume (94) contained by the same end walls between the middle belt (44) and the outside belt (45). The surfaces of the middle belt (44) are oleophilic or oil attracting and, when the mixture (93) passes through the belt apertures (96), bitumen, including bitumen wetted minerals, separates from that mixture and attaches to corresponding belt sur-faces when it comes in contact with the belt. This captured bitumen (16) accumulates on the moving belt and is conveyed upward and out out of the mixture past the interface (14) and past the conveyor roller (8) belt support to the top flight (6). The direction of belt movement is shown with the arrow (80).
The bitumen depleted mixture that has passed through the apertures (96) of the middle belt continues on from there and flows through the apertures (97) of the outside belt where residual bitumen from the mixture adheres to the belt surfaces of the outside belt and then the mixture leaves through the tank outlets (42, 101). The additional bitumen (15) captured by the outside belt from this mixture is conveyed to the corresponding top flight (5). The di-rection of belt movement is shown with the arrow (80) and isthe same for both belts since the outside belt rests on the middle belt along the top flights (5,6). When separate conveyor supports are used for these two belts, the belts may move in the same direction as the arrows (80) of Figure 1,. or the belts may move in opposite direction to each other if so desired.

~3~

The middle belt (44) and the outside belt (45), there-fore, provide for two stages of separation of bitumen from - the mixture before the mixture leaves the separator. In some cases only one such stage is required or preferred. In S that case, the outside belt is not used and the inside belt is made longer in order for its inverted arch bottom flight to assume the shape resembling the shape of the inverted arch of the outside belt of Figure 1. Alternately, three or more nested belts of different lengths may be used.
Bitumen (15 and 16) continues to accumulate on the belt surfaces that are immersed in the mixture and increases in thickness as the belt surfaces convey through the mixture from right to left in the Figure. While these surfaces are emerged, there is little tendency for this captured bitumen to fall from these belt surfaces as buoyancy of bitumen in the mixture helps to keep it there. This bitumen emerges from the mixture at the interface (14) and is conveyed to the top flights of the middle (44) and the outside (45) belts as it passes the conveyor roller (8). The belt sur-faces (24) that emerge from the interface (14) move in analmost vertical direction and, as a result of that vertical movement there is little tendency for bitumen to fall from the belt surfaces (24), especially as the two belts (44 and 45) merge in that general area and trap bitumen between them. However, after passing the conveyor roller (8) the belts become approximately horizontal and, being un-im-mersed, there is a greater tendency from bitumen to drip (7) or fall from the top flights (5,6). This removal of bitumen from the top flights is further assisted as the top flight pass jets (1) or nozzles of warm circulating water that flood the belt. The flow diagram of this warm water (77) is shown in Figure 4. Warm circulating flood water and bitumen (3) fall off the top flight onto a sloping roof (22), which dumps this stream into a chute (35) that directs this stream into an inside compartment (38) that is separated from the main separating mixture (93) by means of an insulated wall enclosure (10).

~3~, L~

As the belt surfaces of the top flight (5,6) of the middle (44) and outside (45) belts convey further to the right, these encounter nozzles of fresh cold water that com-plete the removal of most of the bitumen from these two top flights before the belt surfaces return to the separating mixture as bottom flights. The flow diagram of the water (68) supply to the cold water nozzles is shown in Figure 4.
This cold water is the make up water required to replenish the circulating stream of water (77) as is explained in the description for Figure 4. Thermal energy is conserved by not pre-heating this stream of water as there is little to be gained from heating the belt surfaces that are on their way back to the bottom f lights and to the separating mix-ture, as in the preferred operation of the present invention the bottom flight is colder than the top flight. Bitumen (4) and cold water falling from the top flights onto the sloping roof (22) flow into a second chute (36), which di-rects it into the same inside compartment. An apertured inside endless belt (34) is mounted in this middle compart-ment (38). It is supported by a conveyor roller (23) at theleft and a shaft (21) with sprockets (25) at the right.
Location of these sprockets (25) on the drive shaft (21) is shown in perspective in Drawing 3.
Unlike in the outside tank (41), flow in the inside compartment through the belt apertures (98) is from the out-side of the inverted arch bottom flight to the inside of that arch. This is achieved by withdrawing mixture through a pipe (30) from inside of the bottom flight of the inside belt (34) as described in more detail in the description of Figure 4. The bitumen product (3,4) falling from the top flights of the middle (44) and outside (45) belts contains large amounts of water and a significant amounts of hy-drophilic and oleophilic minerals in the form of sand, silt, clay and particles of titanium, zirconium and iron minerals, garnets etc. It represents an intermediate bitumen product highly diluted with water. Rs this intermediate product passes through the apertures (98) of the inside belt (34), 2 ~ 7 bitumen separates from that product and is captured by and adheres to the surfaces of the moving belt . This captured bitumen (33) which increases in thickness on the belt sur-faces (27) as these move from right to left until these emerge from the interface (26), passes by the conveyer roller (23) support and becomes part of the top flight (20).
Water and a large portion of the hydrophilic minerals of this intermediate product pass through the belt apertures (98) and leave the inside compartment through the outlet (30)-These hydrophilic minerals (sand, silt and hydrophilicclay) were originally carried by the bitumen coated belt surfaces of the middle (44) and outside (45) belts as these emerged from the interface (14), were occluded in this bitu-men (15,16) coating these belt surfaces, or were carriedsuperficially on the outside of this bitumen. However, as this bitumen passed by the warm~water jets (1) and by the cold water nozzles (2) superficial solids were washed off and occluded hydrophilic mineral particles were exposed and all became part of the water phase of the intermediate product flowing into the chutes (35 and 36) and into the inside compartment. As these hydrophilic particles subse-quently passed through the belt apertures (98) of the inside belt, these were generally not captured with the bitumen ( 33) on the belt surfaces (27) but mostly left the inside compartment (38) with the water phase through the outlet (30). Oleophilic minerals, however, have an affinity for bitumen and are captured mostly with the bitumen phase (33) adhering to the belt surfaces (27) and are conveyed to the top flight (20) past the conveyor roller (23) along with the bitumen. This bitumen is warmer than the bitumen (15 and 16) adhering to the middle and outside belts and, as a re-sult falls off the top flight more readily. This generally means that the inside belt (34) may have to move faster than the middle (44) and outside (45) belts to prevent flow of bitumen (33) downward along the belt surfaces (27) as these emerge above the interface (26). Often a portion of this ~ ~ ~ 3 ~ ~ d warm bitumen leaves the top flight (20) and adheres to the conveyor roller (23). A scraper ~19) not touching, but in close proximity to the surface of, the roller (23) removes the accumulation of bitumen from that roller and directs it into a bitumen receiver (32).
Nozzles of steam (17) blow down onto the top flight (20) and serve to assist in the removal of bitumen from that top flight. This steam may be saturated steam or it may be superheated steam under high pressure. When this steam is superh~ated, it serves partly to remove water from the bitu-men on the top flight (20) , resulting in a dryer product than when saturated steam is used. However in some cases, saturated steam is preferred to keep the bitumen product sufficiently wet for subsequent dilution centrifuging, and to conserve energy. The final bitumen product (18) leaves the receiver (32) through a pipe (31) and may be pumped or flows by gravity for subsequent clean up and for upgrading to synthetic crude oil or for making asphalt. Some solids in the steams (28 and 29) entering the inside compartment tend to settle along the compartment wall (10) and accumu-late in the bottom of this inside compartment (38). A re-volving cavity lock (39) is provided to permit these solids to pass through the bottom outlet (37) of the inside com-partment to become part of the separating mixture (93) in-side the bottom flight of the middle belt (44). If so de-sired, the whole separator may be totally enclosed with a roof (43) and sides, or the top may be left open for ease of operation and maintenance.
While the conveyor supports ~8, 23) at the left of Figure 1 are described as being conveyor rollers, these may also be stationary conveyor supports over which the belts (44,45,34) slide as these belts are driven by the driven roller supports (11, 21) at the right of Figure 1. Such stationary supports are well within the scope of the present invention. Hence, the rolling supports at the left of Figures 2,3, 8,13,14,15 and 16 may all be replaced with ~ ~ 3~J

stationary supports over which the belts are pulled by driven rolling supports at the right of these same Figures.
In some cases it may be advantageous to wash off the superficial hydrophilic minerals adhering to the bitumen (15,16,33) on belt (45,44,34) surfaces emerging from the interface (14,26) with the use of fine sprays of water from nozzles (133). When this is done, bitumen falling from the corresponding top flights (5,6,20) in most cases will be lower in hydrophilic minerals content and will be of higher quality. In Figure 1 nozzles (133) are only shown washing superficial hydrophilic minerals from the bottom flight of the outside (45) belt. Similar nozzles may be installed above the interface (14) adjacent to the inside of the mid-dle belt to wash superficial hydrophilic minerals from the middle belt bottom flight surfaces after these emerge from the interface FIGURE 2.
The operation of the separator of Figure 2 is identical to that of the separator of Figure 1 with the ex-ception that flow of mixture in the inside compartment through the belt apertures (98) is reversed. The interme-diate bitumen, water and minerals product (3,4) that falls off the top flights of the middle (44) and outside (45) belts, or that is washed from those top flights with the help of jets (1) of warm circulating water or nozzles (2) of cold water fall onto the sloping roof (22) of the middle compartment and then flow through elbows (46,50,51,52) and through pipes or chutes (49 , 56) that direct this mixture (3,4) to the inside of the of the inverted arch of the in-side belt (34). This mixture passes through elbows (46 and 50) that direct this flow of mixture through the end walls (99 and 100 of Figure 3) to the outside of the separator, or at least to the outside of the middle compartment (See Figure 12). This mixture then flows through downward slop-ing pipes or chutes (49 and 56) into other elbows (51 and 2~ 3r) 52) that direct the mixture back into the inside compart-ment. In this manner, these pipes or chutes conduct the mixture around the belt (34), so that the mixture enters the inside compartment (38) inside the inverted arch of the in-side belt (34). This mixture (53 and 54) flows through the belt apertures (98) to the outside of the inverted arch of the inside belt (3~) and is then removed through an outlet (55) as described in the description of Figure 4. Minerals that accumulate in the bottom of the inside compartment can pass through a restriction in the bottom outlet (37) of that compartment to become part of the separating mixture (93) of the middle belt, but most of these solids become part of the circulating water stream leaving through the outlet (55).
Except for these differences noted, operation of the sepa lS rator of Figure 2 is similar to operation of the separator of Figure 1.

FIGURE 3.
Figure 3 is a perspective drawing of a portion of the separator of Figure 2. It consists of a tank (41) with bottom outlets (42) and side outlet (101), which tank has a front wall (99) and a rear wall (100), which are provided with bearing mounts (59) to accommodate support of the shaft (58) of the conveyor roller (23) and of the shaft (21) with sprockets (25) of the inside compartment to support the in-side endless belt (34). The walls of this inside compart-ment are not shown in this drawing, as that would have added to the complexity of the drawing. This separator uses only one endless belt in the main tank (41), and not two as in Figures 1 and 2,. The Conveyor roller (8) shaft (9) sup-porting the belt (5) in the main tank (41) is mounted in bearings (60) in a steel support structure (61). The drive shaft (11) with sprockets (12), supporting the outside belt is also mounted in bearings (62 and 65) and is driven by an A.C. gear motor (63) that is controlled in speed by a vari-able frequency power source. The drive shaft (21) and sprockets (25) of the inside belt is also driven by a simi-~s3~

lar gear motor (64). Inlet and outlet pipes for mixture flow (31,40,55 and 57~ are shown in the front wall (99) and may also be mounted in the rear wall (100) sy-pass chutes or pipes (49 and 56) for passing mixture around the edges of the inside belt (34), to allow it to flow through the aper-tures (98 of Figure 2) from inside to outside of the belt (34), are shown in the front wall (99) and are also mounted in the rear wall (100) hidden in the drawing. Bitumen re-ceiver (32) and the sloping roof (22) of Figures 1 and 2 are needed for proper operation, but are not shown in this Figure of a partly assembled separator.

FIGURE 4.
A flow diagram of water supply to the nozzles and/or jets (1 and 2) of Figures 1 and 2 is shown in Figure 4. Cold water (66) from the top levels of a mined oil sands tailings pond, or from some other source, is pressurized with a pump (67) and becomes the supply water (68) to the nozzles (2) at the right of the drawings along the top flights. This water may also be warm if so desired.
However, in most cases it is not desirable to heat this wa-ter for supply to the nozzles (2) if such water is readily available cold. This water (68) provides make up water for the circulating stream of warm water (69) that flows to warm water jets or nozzles (1).
Warm water (69) is withdrawn from outlet 30 of Figure or from outlet 55 of Figure 2 and is pressurized with a pump (70). This water contains mineral particles, which must be removed before this warm water enters the jets or nozzles (1). This is done by passing the pressurized warm water (71) through one or more hydrocyclones (72 and 73). The un-derflow (74) from these hydrocyclones contains most of the coarse solids, which may be returned to the separator of Figure 3 through a separate inlet (57), or is fed directly into the main inlet (40 of Figures 1 and 2) along with the sludge, slurry or mixture supply for separation. The under-flow (74) from the hydrocyclones ~72 and 73), may blend with r~

the main feed to the separator for subsequent capture of bitumen from that stream along with capture of bitumen from the main feed as this passes through the belt apertures ~96 and 97) to the outlets (42 or 101). Alternately, the under-flow may be discarded into, for example, a tailings pond.
The overflow (75) from the hydrocyclones is moderately warm water from which most of the coarse solids has been removed.
This overflow is passed through a heat exchanger (76) sup-plied with heat from steam (78) or from any other suitable source of heat to produce a warm water feed (77) to the jets or nozzles (1). The temperature of this water (77) is con-trolled to achieve the objective of bitumen removal from the top flights of Figures 1 and 2 in the most cost effective manner. This temperature is influenced by the types of belts used in Figures 1 and 2, by the temperature of the bitumen (15,16) emerging from the interface (14), by resid-ual diluent content of this bitumen added to sludge by the main oil sands plants, which affects its viscosity, and by the pressure of the circulating water (77) from the pump (70) When this pressure is high a lower water temperature is needed to remove bitumen from the top flights (5 and 6), whereas, when the pressure of water (77) is low, the tem-perature has to be higher to achieve the desired objectives of bitumen removal. The temperature of this circulating wa-ter preferably is 30 degrees centigrade or higher.

FIGURE 5.
Figure 5 is an illustration of the construction of a flat wire belt. It is used in the fabrication industry for conveying machine parts, and in the fishing industry and in the logging industry for various conveying purposes. It is also very convenient for use in the present invention.
It consists of flat strips of metal, approximately 1 to 1.25 centimetre wide and is available in various strip thick-nesses. Normally each strip (81) is approximately 1 to 1.5 millimetres thick. It is pre-punched with holes (91) and is bent in the shape of a deformed square wave as shown in Figure 5. The flat strips after bending are placed next to each other, as shown in the Figure, and round rods (82) are pushed through the holes (91) to join these strips (81) into a continuous belt that is as wide as desired by using strips of an appropriate length. Flat wire belts are available in various widths ranging from 10 centimetres to 5 meters or wider. The rods (82) are bent at the ends, or are enlarged at the ends by welding or forging, to keep them in place, to make the belt uniform in width, and to prevent the rods from passing out of the holes of the punched s~rips during oper-ation. These belts are available in mild steel, high ten-sile steel and in various steel alloys. Most of these work well in the present invention and, in particular, type 304 stainless steel is suitable, as it has good affinity and adhesion characteristics for many bitumens. The preferred type of metal to be used for the construction of this belt in the present invention depends on the type of mixture to be separated, and required some preliminary test work with ~ the apparatus of Figures 1 or 2. The design of this belt makes it very suitable for engagement with sprockets that are especially designed for this type of belt to drive the belt with a drive shaft. Sprockets (12 and 25 of Figure 3) are placed on and fixed to drive shafts (11 and 21) approx-imately 10 to 20 centimetres apart. These sprockets may be made from cast iron, from steel or from ultra high density polyethylene. Sprockets constructed from this polyethylene provide very good wear resistance in the present invention for both sprockets and belt. It is noteworthy that in the design of the separator of the present invention shown in Figures 1, 2 and 3, the sprockets (12 and 25) engage with the belts (6 and 20) after most of the bitumen and minerals have been removed from the top flights (5,6,20). As a re-sult of this placement, abrasion of sprockets and belt are minimized. However, if so desired, this belt may also be 3S driven by fiction. In that case, the sprockets on the shafts (11 and 21) are replaced with rubber lagged conveyor rollers, and a pressure roller may be provided adjacent to 2~32:~

each rubber lagged roller to press the belts against the rubber lagged rollers and cause them to be moved by fric-tion. In some cases these pressure rollers are not required as the weight of the belts supported by these rubber lagged rollers provide sufficient friction to drive them without slip. A top view of the belt is show at the left in Figure 5 and a side view of the belt is shown at the right in Figure 5.

FIGURE 6.
Figure 6 is an illustration of the construction of a spiral mesh wire belt. Such belts are used in industry for conveying machine parts and for other conveying applica-tions, and come in a variety oE sizes, belt meshes and mate-rials of construction. Belts of various metals of construc-tion work well for the belts of the present invention and, in particular, spiral mesh wire belts made from stainless steel type 304 work very well. These belts consist of al-ternate clockwise (85~ and counter clockwise (83) wound wire spiral coils that are joined with cross rods (84) to form an endless belt. A top view of the spiral wound belt is shown at the left in Figure 6~ The spiral coils are flattened, as shown in the side view of Figure 6 in the middle of the page. At the far right of Figure 6 are shown two types of belt construction that are commercially available. The top illustration (86) is of a spiral mesh wire belt in which the spirals are joined with cross rods. In the bottom illus-tration (87) the alternate clockwise and counter-clockwise spirals are twisted into each other to form a continuous belt without the need for cross rods. However for the pur-pose of the present invention, a construction (86) using the cross rods is preferred.

FIGURE 7.
The construction of a roller belt that use a mul-tiplicity of linkages (90), rollers (89) and cross rods (88) 2~32~ 7 is illustrated in Figure 7. This belt is more costly to construct than the belts of Figures 5 and 6 but it has a number of advantages for the present invention. It can be made from a variety of metals or from plastics, such as, for example polypropylene or ultra high density polyethylene.
It can use commercially available sprockets to drive the belt and, as the rollers (89) are free to revolve on the cross rods (88), wear of the sprockets and belts may be less than when belts similar to Figures 5 or 6 are used.
Construction of the belt consists of a large number of cross rods that are enlarged at one end. Pre-punched linkages and rollers are then placed alternately on these cross rods for the full length of the cross rods. The other ends of the cross rods are then enlarged by welding or by a fastener to prevent rollers (89) or linkages (90) to come off the cross rods (88). A top view of the belt is shown at the left of Figure 7 and a side view is shown at the right of the Figure. The pre-punched holes (92) are shown in the side view. The linkages (90), as shown in the side view are cut off square. However these may also be rounded at the corners if so desired. ~hen the linkages are made from molded plastic or from cast, pressed or forged metal or ma-terial, the holes in the linkages may be put in as part of the molding, casting, pressing or forging process.
Similarly, the rollers may be molded, cast, sintered, pressed or forged to the desired shape.

A perspective drawing of a typical endless belt of the present invention is shown in Figure 8. It uses the belt construction detailed in Figure 5. This belt may be used for either the middle belt or the inside belt, or both.
For that reason, numbers to identify parts on this drawing for comparing with Figures 1 and 2 are shown for both belts using the same numbers for the various components. This same mode of using the same numbers to identify similar com-ponents between Figures is used throughout these descrip-3~

~3~ 3 ~ ~ I

tions. Two conveyor rollers on shafts support this belt.The left roller ~8 or 23) is similar to one of the two left rollers of Figures 1 and 2. The right roller is a rubber lagged roller for driving the belt by friction. It is sup-ported by a shaft (11 or 21) similar to the shafts at theright side of Figures 1 and 2.

An estimate of the amount of sludge accumulating in mined oil sands tailings ponds, at the end of each year from 1987 to 2nl8, is shown in Figure 9, along with the amount of bitumen accumulating in that sludge. The compu-tations forming the basis for the drawing are based on the assumption that both Suncor and Syncrude will proceed with their proposed plant expansions, that the proposed OSLO
plant will come on stream by the year 2000 and that Suncor will start a new mined oil sands plant of the same capacity as its old plant when the current Suncor oil sands lease runs out in the year 2004. The prediction presented in this Figure is based on the performance of the Clark Hot Water process currently in use by Suncor and Syncrude and incor-porates future improvement in plant performance projected by these two companies. The predicted amount of sludge that will be accumulating is based on the amount of synthetic crude oil that will be produced by these three plants, and upon the ratio of sludge generated versus synthetic crude oil produced. The amount of bitumen accumulating in that sludge is estimated from the amount of lost bitumen that is not recovered in the Clark Hot Water process. Part of the bitumen is lost with the oversize rocks and lumps of clay that are not digested when oil sand slurry is produced. The remainder of the lost bitumen is found in the tailings stream. However, when this tailings stream is discarded at the shore of tailings ponds, a small portion of this tail-ings bitumen remains with the sand on the pond shore, whichis used to build tailings pond dykes. The remainder of the tailings bitumen, representing the bulk of the lost bitumen 2-~3321~

flows into the ponds and becomes part of the sludge. It is this portion of the lost bitumen that is shown with the solid curve of Figure 9 in millions of barrels of lost bitu-men. The amount of this bitumen in cubic meters may be computed by dividing the numbers on the left vertical axis in millions of barrels by the conventional 6.29 factor.

FIGURE 10.
A history of ultimate bitumen reserves in Alberta oil sands, as estimated on an annual basis by the Alberta Energy Resources Conservation Board, is shown in Figure 10. As shown in this Figure, ultimate bitumen reserve estimates have increased from 900 billion barrels in 1972 to 1700 billion barrels in 1986 and have remained largely unchanged to the present day. Approximately 10% of this bitumen re-serve may eventually be mined as technological improvements make this mineable oil sand economically viable for devel-opment. When in future 10 mined oil sands plants each ex-tract 100,000 barrels of bitumen per day at a conversion efficiency of 95% from bitumen to synthetic crude oil; the total production from these Alberta plants will be 950,000 barrels of synthetic crude oil per day or 347 million bar-rels per year (55 million cubic meters per year). At full production, the mineable oil sands reserve of Alberta will be able to supply these ten plants with oil sand ore for over 400 years. It is expected that in future mined oil sands plants will be of various sizes. Some will produce well over 200,000 barrels of oil per day while others may produce less than 50,000 barrels per day.

An annual history of the percent bitumen recovery from mined oil sands with the Clark Hot Water process is shown in Figure 11 for the Suncor mined oil sands plant. In this Figure, the line represents the average annual bitumen recovery achieved from mined oil sands, and the bars repre-sent the average grade of oil sands mined during each year 2 ~

on the basis of weight percent bi~umen in the ore. ~ simi-lar plot was prepared by the inventor for the Syncrude plant from data available for the Alberta Energy Resources Conservation Board. Both these graphs, and other informa-tion supplied by Suncor and Syncrude, were used for pro-jecting and computing data for the graph of Figure 9. The percentage of lost bitumen may be computed from the graph of Figure 11 for each year by subtracting the data of the solid ~ line from 100%. The annual amount of lost bitumen may thus be calculated from this percentage difference for each year and from the amount of bitumen in the ore that was mined each year, and that is projected to be mined for each future year. Future projections of lost bitumen may then be made by multiplying projected future bitumen recovery with pro-jected amounts of bitumen in annual amounts of oil sands mined. The data of Figure 9 was obtained when these annual calculations and projections were accumulated over the 1987 to 2018 period.

FIGURE 12.
A partially assembled separator is shown in Figure 12 to show a construction option in which the inside com-partment (104) of the separator is not part of the main tank ~ front and rear walls (41, 100). This is done to facilitate maintenance and repair. As a result of this design, all moving parts are supported by the main structural frame (61). The roof (22) of the inside compartment of Figure 2 is mounted on brackets on this same frame (61) so that it can be unbolted and removed. The inside compartment (104) is also mounted on brackets so that it can be unbolted from the same frame (61) and the bitumen receiver (32 of Figure 2) can also be unbolted separately from the inside compart-ment and from the bitumen outlet pipe (31). With this type of construction it is possible to assemble all three belts (34, 44 and 45 of Figure 2) on their conveyor supports (8, 11~ 23 and 21 of Figure 2J on the main frame (61) when that main frame is suppor~ed temporarily with pillars or from a ~32~7 crane ~not shown). Maintenance can then be performed on each of the three belts and on the moving shafts and bear-ings attached to the main frame (61). After completing of this maintenance work, the inside compartment (104) may be bolted back onto the frame (61) along with the bitumen re-ceptacle and the sloping roof of the middle compartment.
After that, the whole assembly may be lowered into the main separator tank and secured to the tank walls (99, 100) be-fore the apparatus is put back into operation. This design permits for ease of construction and allows for periodic inspections of the apparatus when there appears to be a malfunction. It also permits for convenient assembly of belts on their ~onveyor supports, and prevents damage or deformation of the belts during apparatus assembly or during belt replacement. As shown in Figure 12, sloping chutes or pipes (49 and 56) for by-passing intermediate bitumen and water mixture around the belt (34) edges as done in Figure 2 are mounted in the end walls of the middle compartment (104). This makes its necessary for the length of the mid-dle compartment 104 to be less than the length of the main separator tank (41) side wall. As a result, in this design, the belt width of the inside belt in the middle compartment (104) is less than the belt width of the middle and outside belts in the main separator tank (41).

The deflection (107) of a top flight (123) of an endless apertured belt constructed according to the con-struction details of Figures 5, 6 or 7 and supported by two conveyor supports only (119 , 120) is shown in Figure 13.
For a belt at rest, freely supported by conveyor roller supports (119, 120) of a reasonable size (20 centimetres in this case) on freely revolvable shafts (119 and 124), in which the deflection (105) of the inverted arch bottom flight (122) is equal in dimension to the width (106) be-tween the centres of the two roller supports (119 and 120), the deflection (107) of the top flight (123) is approxi ~332~. ~

mately 10% of the deflection (105) of the bottam flight.
This is the case for steel belts in which the bottom flight is immersed in sludge to the approximate level ~126) indi-cated in Figure 13. The deflection (105) of the bottom flight (122) is defined as the distance between the centre line of the two support shafts (121 and 124) of the outside supports (119 and 120) and the very bottom of the inverted arch of the bottom flight (122). The deflection (107) of the top flight (123) is defined as the distance between a line drawn along the very top of the actual belt conveyor supports and the very bottom of the deflected top flight (123). The same definitions are used in Figures 14,15 and 16.

The deflection (110) of the the top flight (123) of the same endless apertured belt o~ Figure 13 is shown in Figure 14 for the case where a third conveyor roller (127) support is placed along the top flight (123) at the mid point (distance 108 equal to distance 109) between the two outside supports (119 and 120) and with the shafts of all three rollers in horizontal alignment and free to turn. In this case the deflection (110) of the top flight between the three supports is approximately 2% of the deflection (105) of the bottom flight (122) of Figure 13.

The deflection (114) of the the top flight of the same endless apertured belt of Figure 13 is shown in Figure 15 for the case where a third (128) and a fourth (129) con-veyor roller support are placed along the top flight (123) equally spaced (distances 111, 112 and 113 are equal) be-tween the two outside supports (119 and 120) and with the shafts of all four rollers in horizontal alignment and free to turn. In this case the deflection (114) of the top flight (123) between the four supports is approximately 0.6 2033~7 of the deflection (105) of the bottom ~light (122) of Figure 13.

This Figure is identical to Figure 15 with the exception that the two middle rollers have been replaced with smooth stationary conveyor guides (103) similar to the conveyor guides along the top flights (5 and 6) of Figures 1 and 2. As in Figure 15, the deflection along the top flight of of Figure 16 is approximately 0.6~ of the bottom flight of Figure 13.
The purpose of these last four Figures is to show that it is relatively easy in the present invention to have the `:.
top flight of each belt approximate a relatively straight and horizontal top flight by the addition of two revolving or stationary belt supports below the top flight. These supports are shown in Figures 1 and 2 for the middle and outside belts and would normally be used for the lnside belt as well.
In the present invention, top flights assuming or approximating generally horizontal paths must be interpreted in the context of the descriptions of Figures 13 to 16. It means that the top flight deflections do not exceed 10% of the bottom flight deflections, and that one belt support is horizontal with or less than one such top flight deflection distance above or below another belt support.
Alternately, supports may be provided between the two inside (23,21) or the two outside roller supports (8,11) in direction parallel with the direction of belt movement (79,80). For example, steel bars, or steel bars covered with ultra high density polyethylene wear strips, placed 20 centimetres apart, or less, each bar connecting a location close to one roller support (8,23) with a location close to the other roller support (11,21) may be used as auxiliary belt supports to limit the deflection of the top flight to yield a straight and horizontal top flight or to yield a ~,~33~

top flight that approximates a straight and horizontal top flight.
As mentioned in the description of Figure 1, while the conveyor supports at the left in Figures 1,2,3,8,13,14,15 and 16 are all shown in the Figures as roller supports, these may also be stationary supports, over which the belt surfaces slide to conver~ from bottom flights to top flights as these belts are driven by roller or sprocket shaft sup-ports at the right of these Figures. Thus in Figures 13,14,15 and 16, supports 119 may be stationary supports over which the bottom flights (122) slides to become top flights (123) whereas supports 120 are sprockets on shafts (124) or rubber lagged rollers (120) that drive the top flights (123) and bottom flights (122) of the belts.
Thus the present invention uses two, three or more nested flexible apertured endless belts to recover a greater percentage of bitumen from a mixture of bitumen, water and mineral particles than the prior art, and/or to remove water and hydrophilic minerals from the resulting intermediate bi-tumen product. In Figures 1 and 2, two nested belts are used to recover bitumen from a separating mixture and a third nested belt is used to remove water and hydrophilic minerals from the intermediate bitumen product, to yield a bitumen product lower in water content and lower in minerals content than in the prior art, suitable for further clean up and upgrading.
To meet the objectives of the present invention, as few as two nested belts or as many nested belts as desired may be used. For example, one of the three belts of Figures 1 or 2 may be removed and the resulting two nested belts will meet the objectives of the present invention of using two or more nested belts. When the inside belt (34) is removed, the separators of Figures 1 and 2 become a two stage device for improving the recovery of bitumen from a mixture. In that case the middle compartment may be removed and the bi-tumen receptacle (32) enlarged to collect bitumen falling 2 ~

from the two top flights (5 and 6). when, in stead, the outside belt (45) is removed, the remaining two belts (34 and 44) are still nested and meet the objective of the pre-sent invention. However, in this case both belts are sup-ported by separate roller supports (8,12 and 23,25) and each recovers bitumen and oleophilic minerals from a different mixture. The one belt (44) recovers bitumen and oleophilic minerals from the separating mixture and the other belt (34) recovers bitumen oleophilic minerals from the bitumen, water and minerals intermediate bitumen product of the top flight (6) of the first belt to yield an improved bitumen product.
In stead of two or three belts, more belts may be used as well. For example, a fourth belt may be installed in the separators of Figures 1 or 2 without making major changes to the construction of these separators. This may be done by placing another belt around a shortened inside belt (34), and placing its top flight on top of the top flight (20) of the inside belt (34). In this case the two belts then re-siding in the inside compartment (38) provide for two stages of bitumen recovery from the intermediate bitumen product.
As a result, the underflow (74) and/or the overflow (75) of the hydrocyclones (72 and 73) of Figure 4 may contain less bitumen than is the case when only one inside belt (34) is used. In some cases this is desirable.
In Figure 1 the flow of mixture for separation through the apertures (98) of the inside belt (34) is from the out-side of the bottom flight to the inside of the bottom flight. The flow of mixture for separation through the apertures (96 and 97) of the middle (44) and outside (45) belts is from the inside of the bottom flights to the out-side of these bottom flights. Thus, in one separator, the flow direction of mixture through the belt apertures may differ from belt to belt. In Figure 2 the direction of flow of separating mixture through the apertures (96, 97 and 98) is the same, from inside the bottom flights to outside the bottom flights. Both Figures 1 and 2 meet the objectives of the present invention of using two or more nested belts but 2~32:~ 7~

the direction of flow of mixture through the belt apertures of the bottom flights does not have to be the same.
In the case of the middle and outside belts of Figure 2, the outside belt bottom flight serves as a bitumen scav-S enger to capture bitumen from the separating mixture that was not captured by the bottom fligh~ of the middle belt.
In this case, flow rate of separating mixture is not in-creased or decreased significantly by the addition or re-moval of the outside belt but, in most cases, more bitumen is collected from the separating mixture when two belts are used in stead of when only one belt is used for the primary separation, irrespective of the operation of the inside belt in the inside compartment.
In cases where the flow rate of mixture through the bel~t apertures of a single belt is increased significantly, the addition of a second or third belt will assist in main-taining high percentage bitumen recovery, whereas with one belt such bitumen recovery will in most cases degrade as flow rates are increased very significantly.
The concept of allowing flow direction of separating mixture through apertures (96 and 97) in the bottom flights of two nested belts (44 and 45) in opposite directions makes it possible to significantly increase flow rate of mixture through one separator. This is shown in Figure 1 when sepa-~S rating mixture is allowed to flow into the separator through inlet 130 , out of the separator through outlet 42 and also out through the old inlet (40) which has now become an out-let for mixture after separation. In this case, mixture for separation is introduced into the volume or cavity between the bottom flights of the middle (44) and outside (45) belts. Separating mixture flows through the apertures (97) of the outside belt outward from the inside of the bottom flight of this outside belt to outside of this bottom flight, and leaves through -the bottom outlet (42).
Separating mixture therefore also flows through the aper-tures (96) of the middIe belt inward from the outside of the bottom flight of the middle belt (44) to the inside of that ~3~17 bottom flight, and leaves through the new outlet (40) that used to be an inlet in prior descriptions of operation of Figure 1. Operating the separator of Figure 1 in this bi-directional mode has a number of potential advantages that include a potential for increasing the throughput of sepa-rating mixture through the separator~ as well as a potential for separating the effluent stream of separation into a bottom stream that is high in mineral content and an upper stream that is low in mineral content. This is because coarse settling solids in the separating mixture will have a greater tendency to flow through the apertures (97) of the outside belt than through the apertures (96) of the middle belt.
For a constant flow rate of mixture through the belt apertures (96 and 97), the throughput of separating mixture through the separator may be almost doubled when mixture is introduced through inlet 130 in stead of through inlet 40 as described above. The actual flow rate of mixture that may pass through the separator, however, is also influenced by the amount of bitumen that can be carried by the bottom flights of the two belts (44 and 45) and by the rate of movement of those belts conveying bitumen to the top flights (S and 6). As seen from Figures 1 and 2, when the top flight (5) of one belt rests on the top flight (6) of an-other belt, their corresponding bottom flights merge near the interface (14) and capture bitumen (24) between them.
The use of two belts in this manner in most cases allows for increased carrying capacity of bitumen on these belts (44,45) It is also well within the objectives of the present invention to introduce separating mixture through yet an-other inlet (131) and to remove separating mixture, after it has passed through the belt apertures (97 and 96), through the new outlet (40) In this case the flow of separating mixture is from outside to inside of the inverted arch for the bottom flights of both belts. In some cases it may be desirable to remove a portion of this separating mixture 2~3~ L~

from the bottom outlet (42) as well, without it passing through any apertures. This would be case when the sepa rating mixture contains coarse solids that readily separate from bitumen of the mixture by gravity. Removing these S coarse solids before these pass through the apertures (97 and 96) may reduce wear and tear of the belts while finer particles, water and bitumen flow to and through the aper-tures. In this latter application the separator o~ Figure 1 t~uld be a gravity separator in which the separating mixture flows from a side inlet into the separatorO Coarse sand settles to the bottom outlet without passing through the belt apertures but bitumen, water, silt and clay flow to and through the apertures (97 and 96 in cases where two belts are used or 96 in case where one belt is used) to capture bitumen and convey it to the top flight or flights (5 and 6) for removal; and for subsequent removal of water and hy-drophilic minerals in a middle compartment if this is de-sired to achieve the objectives of the present invention of two or more nested belts.
me mixture for separation with the present invention may be any mi~ture that contains bitumen, water and miner-als, and the separator configuration used may vary according to the type of mixture that is to be separated and the ob-jectives to be achieved with that mixture. It may be a slurry of mined oil sands with water; it may be an oil sands sludge; it may be a slurry of mined oil sands with sludge;
it may be oil sands tailings; it may be a slurry of mineral ore or it may be a bitumen product that contains water and hydrophilic minerals. When such a mixture is a bitumen product from another process, only two belts may be required to remove water and hydrophilic minerals from such a prod-uct, or a third belt may be used, such as in Figure 2 to wash additional hydrophilic minerals out of that bitumen product. When the final bitumen product is processed subse-quently with a diluent, such as in dilution centrifuging, it is advantageous to remove as much of the minerals from this bitumen before dilution to minimize solids loading in the 2~3~ 7 subsequent process. When solids loading is reduced in diluent based processes, diluent losses are reduced and higher process bitumen throughputs may be achieved.
In the case of Figures 1 and 2 the top flight of the outside belt rests on the top fiight of the middle belt and is driven by friction between these two top flights as the middle belt is driven by the shaft (11) of the conveyor support at the right of the Figure. This conveyor may be a shaft with sprockets or a rubber lagged conveyor roller that drives the middle belt by friction. In stead of rubber lag-ging, this conveyor roller may be covered with any type of man made lagging material suitable for driving the belt by friction.
In stead of resting the top flight of the outside belt on the top flight of the middle belt, additional conveyor supports or shaft with sprockets may be provided to support the outside belt independently from the middle belt. In either case, the middle and outside belts are nested to meet the objective of the present invention, and a third belt may or may not be required.
The present invention provides, in one apparatus, for the recovery of an intermediate bitumen product from a mix-ture of bitumen, water and mineral particles by means of one or more nested apertured endless belts, and for the removal ~5 of water and hydrophilic minerals from the intermediate bi-tumen product by means of an additional one or more nested belts in that same apparatus. All the belts used in the present invention have top flights that approach in shape generally horizontal flights, with only minor deflection between the supports, and with bottom flights that are in the form of inverted arches with major deflection between the supports. All the belts of the present invention are apertured and have inverted arch bottom flights, and each bottom flight is partly immersed in the mixture that belt is separating, and have top flights that are not immersed.
Guides or guide rollers may be used along the bottom flights to prevent or control swinging of these bottom 2 ~

flights and, in the extreme case, a bottom roller may be located at the very bottom of each bottom flight ~o provide belt tension or to deform one or more of the inverted arch bottom flights into bottom flights that resemble two sides of a triangle The following six examples are provided to explain the function of the present invention for various feedstocks.
These examples are not the results of commercial perfor-mance, as the process has not been tested as yet in a com-mercial plant, but these are provided as a guide only as towhat may be anticipated when the process is used in a com-mercial plant.

Based on current projections for mega-plants, the existing Suncor, Syncrude and proposed OSLO plants wi~l be capable of upgrading up to a combined 140 million barrels per year of synthetic crude oil from bitumen extracted from mined Alberta oil sands. Close to 1700 thousand million barrels (270 billion cubic meters) of ultimate bitumen re-serves of bitumen are estimated to be contained in this Alberta resource, as shown in Figure 10. About 10 percent of that bitumen is currently considered mineable, which makes it possible to operate three such mined oil sands plants concurrently for over 1000 years before this bitumen resource is depleted.
Current mined oil sands plants, such as the Suncor plant, extract bitumen from the mined ore with a Hot Water bitumen flotation process that recovers approximately 90% of the bitumen in that ore, as shown in Figure 11. About 10%
of the ore bitumen is lost in the process. A small portion is discarded with the oversize rocks and lumps of clay that are rejected by the process, and the rest of the lost bitu-men ends up in the tailings of the process which are pumped to large tailings ponds. Upon arrival at the tailings ponds, the tailings are allowed to settle on the shore, where the tailings water, being a good sorting agent, car-~J~33~:~7 ries about half of the silt and clay, and most of the bitu-men of the tailings into the middle of the ponds to continue the settling process. On the shore of the ponds, tailings sand, containing about half of the tailings silt and clay and a small portion of the tailings bitumen is piled up to form dykes to contain the liquid in the ponds. This liquid in the ponds settles into a bottom sludge layer, intermedi-ate settling layers, and a clear water top layer. The sludge layers contain on average 20% to 35% clay and silt, 1 to 7~ bitumen, with the rest being water. In some cases lenses of bitumen accumulate within the sludge, giving local concentrations of bitumen well in excess o~ 7%.
It has been projected by the inventor, as shown in Figure 9 that, by the year 2018, combined bitumen accumula-tion in tailings ponds from Suncor, Syncrude and OSLO minedoil sands plants alone will exceed 1200 million cubic me-ters, and that this sludge will contain approximately 240 million barrels (38 million cubic meters) of bitumen, repre-senting about 3 % percent bitumen by volume. It is the ob-~ective of the present invention to recover between 70 and90 percent of that bitumen contained in tailings pond sludge, representing a total production of between 18,000 and 24,000 barrels of bitumen per day for 25 years. More discarded bitumen is expected to accumulate in sludge as more mined oil sands plants, using flotation processes for bitumen recovery, are built and put in operation.
The inventor proposes that several separators, as il-lustrated in Figures 2,3,4,5 and 6, be used to achieve a production of up to 24,000 barrels of bitumen per day. Each separator (Figures 2 and 3) is approximately 5 meters tall, 3 meters wide and 5 meters long, and uses three nested end-less belts made from type 304 stainless steel. Each of the separators is enclosed, as a tank, to permit containment of sludge for separation by the bottom flights of the belts.
The outer of the nested belts is a spiral mesh wire belt similar in construction to the illustration in Figure 6, using a cross wire construction further illustrated in item 2 ~

8Ç of that Figure. The belt is 5.0 meters wids and 11.3 me-ters long and is joined at the ends to make an endless belt, 6.7 meters of which is immersed in sludge in the tank of the separator. The middle belt of the nested belts is a flat wire belt similar in construction to the illustration in Figures 5 and 8. It is 5.0 meters wide and 10.0 meters long and is joined at the ends to make an endless belt, 5.5 meters of which is immersed in sludge in the tank of the separator. This belt is supported by a conveyor roller, as shown at the left of Figures 2 and 3, and by a shaft with sprockets, as shown at the right of Figures 2 and 3. A
perspective drawing of this belt on its supports is shown in Figure 8. However, in this drawing the shaft with sprockets is not shown in detail. The top flight of the outer belt rests on the top flight of this middle belt as is shown in Figure 2. During separation, sludge is pumped into the in-side of the inverted arch of the middle belt bottom flight, passes through apertures in both the middle and the outside belts and leaves through bottom and side outlets in the separator tank. The shaft with sprockets is driven by a gear motor, as in Figure 3, and causes movement of the mid-dle belt, which engages with the sprockets. The outer belt is conveyed by the middle belt because of contact between the top flights of these two belts.
Bitumen separates from sludge passing through the apertures of the bottom flights of both the outer and the middle belts, is captured by and adheres to the surfaces of these two belts. First sludge passes through the apertures of the bottom flight of the middle belt and leaves bitumen adhering to the surfaces of that bottom flight. The sludge then passes through the bottom flight of the outer belt and additional bitumen is captured by the surfaces of the bottom flight of the outer belt before the sludge leaves the sepa-rator through the outlets of the separator tank. The use of two nested belts to capture bitumen in sequence in this manner provides for a convenient two stage bitumen recovery from sludge system in only one tank.

2~3~2~7 The driven shaft causes movement of the belts in a clockwise manner, and this causes bitumen coated belt sur-faces to emerge from the sludge interface (14) at the left of Figure 2. After passing the left roller (8), bitumen on surfaces of both belts becomes part of the top flights, which first passes by a bank~l) of warm water jets that cause most of the bitumen to warm and fall off these top flights onto a chute. ~emaining bitumen on both flights then passes by a bank of cold water nozzles (2), that con-tribute to the removal of some of the remaining bitumen from the top flights. A thin layer of bitumen remains on the belt surfaces that return back to the sludge after passing the drive shaft with sprockets (12) to again become bottom flights. Bitumen removed from these two top flights, with jets of warm water and with cold water from nozzles, falls onto the sloping roof (22) of an inside separator enclosed by the outer two belts. This intermediate bitumen product (3 and 4) contains water, hydrophilic minerals and oleophilic minerals As illustrated in Figure 2, the inside separator uses a separate conveyor roller (23) at the left and a separate shaft (21) with sprockets ~25) at the right to support an inside endless belt (34). This inside belt is nested with the outer (44) and the middle (45) belts and is of flat wire construction similar to the illustration in Figures 5 and 8.
It is 5.0 meters wide and 5.2 metes long and the ends are joined to form an endless belt. The bottom flight is im-mersed for 2.7 meters in the bitumen-water-minerals mixture it is separating. This inside separator is used to remove hydrophilic minerals from the intermediate bitumen product (3 and 4) of the outside and middle belts and has its own compartment (38) to enclose its inverted arch bottom flight.
Bitumen product from the top flights of the two belts (44,45), washed therefrom with the help of warm water jets and cold water nozzles and falling onto the sloping roGf (22) above the top flight of the inside belt, flows downward past the belt supports, through two or more pipes (49 and 4~

2 ~

56), mounted in the outside end walls (99 and 100 of Figure 3 of the separator, to convey this bitumen, minerals and water mixture to the inside of the inverted arch of the in-side endless belt. The mixture then passes through the apertures of the inverted arch of the inside belt to capture bitumen from this mixture. The captured bitumen is conveyed to the top flight (20~ by the driven shaft (21) with sprockets. This top flight passes by nozzles (17) of su-perheated steam, which blows bitumen from this top flight into a receiver (32), which bitumen flows through a pipe (31) to storage. This bitumen is the final product, con-sisting of a free flowing bitumen product, from which a large percentage of hydrophilic minerals has been removed, but which contains oleophilic minerals and water. The oleophilic minerals and water are subsequently removed in another process before this bitumen product is upgraded to synthetic crude oil.
The flow diagram of warm and cold water in the separa-tor is shown in Figure 4. Cold cIear water (66) from the top of a tailings pond is pumped directly to the cold water nozzles (2) after it has passed a filter (not shown) to re-move debris that may clog the nozzles. Warm water and hy-drophilic minerals mixture, after passing through apertures of the inverted arch of the inside belt leave the inside separator tank through an outlet (55) and are then pumped to a bank of hydrocyclones (72 and 73) to remove a large por-tion of the contained minerals and to hydraulically convey these to the separator inlet (57 of Fig. 3). This inlet is located close to or is part of the main sludge inlet (40) that introduces the mixture into the inside of the inverted arch of the middle belt(44). Water (75) from the top of the hydrocyclones (72 and 73) is heated with a heat exchanger (76), supplied with condensing steam (78) before it returns to the warm water nozzles (l) Only a small amount of steam is needed for this heat exchanger since considerable heat is captured by this circulating warm watar from the superheated steam that is supplied to the nozzles (17) of the inside 2 ~ 3 ~

separator to blow bitumen product from the top flight ~20) of the inside belt. The wall of the inside compartment (38) is insulated to reduce the flow of heat from the mixture in the inside compartment(38) to the cold sludge in the outside tank (41).
Total area for flow through the apertures of the in-verted arches of the outside, middle and inside belts at 40%
average open area are respectively 13.4, 11.0 and 5.4 square meters. The flow rate of sludge through the separator of this example is 7 cubic meters per minute or 10,000 cubic meters per 24 hour day containing on average 3% bitumen by volume for a total content of 300 cubic meters of pure bitu-men per day. At an average recovery of 80% the final bitu-men product consists of 429 cubic meters or 2696 barrels per day of bitumen product containing 56% bitumen, representing 1510 barrels of pure bitumen per day. The composition of bitumen in the separator of this Example is shown in Table 1.

TABLE 1, COMPOSITION OF BITUM_ Bitumen adhering Bitumen product to the middle and from inside belt outside belts before falling into the water washing receiver Percent Bitumen 48 % 56 %
Percent Mineral 22 ~ 11 %
Percent Water 30 % 33 %
Bitumen/Mineral 2.1 5.1 Bitumen/Water 1.5 1.7 In order to achieve this, the flow rate of sludge through the middle belt apertures avexages 1.05 centimetres per sec-ond, and through the outer belt apertures averages 0.86 2~332~

centimetres per second. Much higher or lower flow rates through the belt apertures are possible to accommodate surges in sludge flow. The wide range of sludge flow rates through the belt ,apertures that can be accommodated elimi-nates the need for intermediate sludge storage between the tailings pond and the separators. In order to achieve a total production of 24,000 barrels of bitumen per day a to-tal of 16 such separators will be required located at vari-ous locations convenient to the tailings ponds from which these draw their supply of sludge. Extra stand-by separa-tors may be installed as well to accommodate repair and maintenance. However, the high surge capacities of these separators make it possible to shut down 25~ of the in-stalled separators for maintenance purposes and to direct the excess sludge flow through the remaining 75~. This in-creased flow rate through each functioning separator will slightly reduce the percent bitumen recovery from sludge and will require an increase in drive shaft RPM to accommodate the increase in bitumen accumulating on the belts.
A production of 429 cubic meters of bitumen product per day from sludge or 0.3 cubic meters per minute, spread over the S meter wide inside belt at an average thickness of 1 centimetre emerging from the mixture, results in a belt speed requirement of approximately 6 meters per minute.
With 20 centimetre diameter sprockets engaging with the in-side belt, the drive shaft of the sludge separator turns at about 10 RPM.
To produce 429 cubic meters per day of final bitumen product from the inside belt, the middle and outside belts release slightly in excess of 500 cubic meters of bitumen product per day from the top flights. An average thickness of 1 centimetre spread over two 5 meter wide belts results in a belt velocity of of 3.5 meters per minute. With 20 centimetre sprockets engaging with the middle belt, the drive shaft driving the middle belt turns at about 6 RPM
The gear motors of both drive shafts are supplied with power from variable frequency power sources to permit ad-~, ~ 3 ? ~ ~ ~

justment by the human operator of the drive shaft speeds to accommodate the desired performance. If bitumen starts to fall off the bottom flights emerging from the sludge or from the mixture, or if bitumen thicknesses on the emerging belts become excessive, the belt speed is too low and the operator increases them. When the thickness of bitumen on the belts becomes too low, the operator decreases the RPM of the cor-responding shaft. In addition to a human operator manually controlling the belt speeds, each separator is also equipped to automatically control the belts speeds by a device which measures the open area of each of the three belts just above the interfaces where the belts emerge out of the sludge or mixture. This is done with light sources and a photo cells controlling the frequency of the power sources driving the lS gear motors that are coupled to the drive shafts. When the apertures of an emerging belt are completely filled with bitumen, the corresponding photo cell mounted outside of the inverted arch of the belt above the interface receives no light from the light source mounted on the inside of the inverted arch above the interface (14,26) and this causes the control circuit to increase the frequency of the power source that drives the gear motor, and results in an in-crease in shaft speed. When the emerging belt is only partly loaded with bitumen, the photo cell receives excess light from the light source and this causes the control circuit to decrease the frequency of the power source and results in a decrease in shaft speed. The desired thick-nesses of bitumen on the emerging belts may thus be selected and the corresponding intensities of light falling on the photocells may be used as set points for automatic control of belt speeds. Automatic speed control of the outside and middle belts is normally done with a light and photocell sensing the bitumen content of the outside belt only, but may also be done with sensing the bitumen content of the middle belt only.
Flow rate of warm water and minerals through apertures of the inverted arch of the inside belt is kept at approxi-~3~ 1~

mately 0.5 centimetres per second to achieve high recovery of bitumen from the water, minerals and bitumen mixture, resulting in a total circulating flow rate through the in-side separator of 1.6 cubic meters per minute or 2333 cubic meters per day. Cold water is supplied to the nozzles (2) at a rate of 240 cubic meters per day, equivalent to the amount of pure bitumen product extracted from the sludge.
The under flow from the hydrocyclones (72 and 73) is main-tained at 248 cubic meters per day. This underflow mixes with cold sludge inside the inverted arch of the middle belt and passes through the apertures of the middle and outside belts before it leaves the separator and is discarded.
Bitumen contained in this underflow therefore has the op-portunity to be captured along with bitumen of the cold sludge. The final bitumen product contains at least 56%
bitumen. Flow rate of warm water through the jets (1) is approximately 2100 cubic meters per day or 1.4 to 1.5 cubic meters per minute, sufficient to flood and blow bitumen from the top flights of the outside and middle belts.
unsaturated steam is used to blow bitumen from the top flight of the inside belt in relatively small quantity, sufficient to blow most of the bitumen from the top flight and to elevate the final bitumen product in temperature to 70 degrees centigrade.

This example is identical to Example 1 with the exception that the inside belt is 4.5 meters wide and is contained in an inside separator tank that slides into the main separator tank for ease of maintenance. These two tanks are illustrated in Figure 12. The outside and middle belts are both 5.0 meters wide and the separator of Example 2 has the same throughput capacity as the separator of Example 1. However, the inside belt of Example 2 moves at a slightly faster speed than that of Example 1. This separa-tor is constructed in such a manner that all the shafts o the belt supports, and all moving parts are mounted on one 2~33~7 frame, which can be lifted away from the main separator tank for ease of maintenance of the belts and moving parts of the separator. The inside tank is mounted on that same frame and can be removed easily to gain access to the inside belt and its support shafts for maintenance purposes as well~

Tailings from a mined oil sands plant are sepa-rated by a separator similar to the separator used in Example 2. However, the bottom of the outside tank is much deeper with side walls that slope at 15 degrees with verti-cal to prevent tailings sand from accumulating inside that tank. Only an outside belt and an inside belt are used and both are flat wire belts made from type 304 stainless steel.
Flow velocity of tailings through the apertures of the out-side belt averages about l centimetre per second and flow velocity of mixture through the apertures of the inside belt is kept below 0.5 centimetres per second. However, since these tailings only contain 0.5% bitumen, the amount of bi-tumen accumulating on the belt surfaces is much less than in Example l and, as a result, the required belt speeds are below one meter per minute.

Mined oil sands, containing 12% bitumen by weight are mixed with warm fresh and circulating water and are tumbled to produce a 60% water content slurry by weight at 50 degrees C. This slurry flows by gravity into the sepa-rator of Example 3 and flows through the apertures of the outside and middle belts at 0.5 centimetres per second.
Bitumen accumulates rapidly on the belt surfaces, necessi-tating belt speeds more than ten times as high as in Example 3. These belt speeds result in circulation in the outside tank and slow down the speed of settling of the sand grains of the slurry inside the inverted arches of the outside and middle belts. Sand of the slurry accumulates and thickens in the bottom of the deep separator tank and is removed to 2 ~ 7 disposal as a thick slurry. Water is withdrawn from the top of the separator, outside the inverted arches, ~or reuse in the production of slurry. It is mixed with hot fresh water as required to produce the desired slurry. Fines, in the form of clay and silt, accumulate in the circulating water and reach steady state concentration in the slurry. Excess fines leave the separator with the sand of the slurry from the bottom of the separator tank. Sodium hydroxide or other chemicals are not needed to achieve effective separation of bitumen from this slurry. The tailings sand sent to dis-posal is conveyed hydraulically to a disposal site and water run-off from these tailings is recycled in the process and heated to make oil sand slurry.
Fresh cold water and warm circulating water are used to blow bitumen from the top flights of the outside and middle belts as described in Example 1 and saturated steam is used to blow bitumen from the top flight of the inside belt.
Saturated steam at 100 psi (690 kPa) pressure is used.
Bitumen produced from mined oil sand slurry normally has a lower tendency to emulsify with water than bitumen produced from sludge; as a result, the bitumen content of this final product contains over 6~% bitumen .

EXAMPLE S
. . . _ Tailings pond sludge from a mined oil sands plant is mixed with mined oil sands ore and is mulled in a tumbler to disperse the oil sand in the sludge in a test facility.
Propane flames impinge on the cylindrical wall of the tum-bler to heat up the mixture in the tumbler to 50 degrees centigrade. Five metric tonnes per day of sludge, contain-ing 5% bitumen, 24% minerals and 71% water are mixed with two metric tonnes of mined oil sands ore containing 11% bi-tumen, 85% minerals and 4% water. The oil sand feed in this Example contains 500 kg of bitumen per day and the sludge feed contains 440 kg of bitumen per day. The composition of the resulting screened slurry, after removal of 500 kg per day of oversize reject is:

~332~7 Bitumen 6.8%
Minerals 40.0%
Water 53.2~

This slurry is separated in a separator similar to the sepa-rator of Figure 2, which recovers a total of 85% of the bi-tumen contained in that slurry resulting in a final bitumen product having an approximate composition of:
Bitumen 59 ~
Minerals 12 %
Water 29 %

Based on total bitumen in the oil sand ore of 500 kg per day, the process has recovered 777 kg of bitumen per day;
more bitumen than was in the original oil sand ore. Based on the co~bined feed of oil sand ore and sludge containing 940 kg of bitumen per day, the 777 kg per day of bitumen represents a bitumen recovery of 83%. The effluent stream leaving the separator through the bottom tank outlet has an approximate composition o~

Bitumen 1.1 %
Minerals 43.1 %
Water 55.8 ~

These effluents are allowed to settle and result in a set-tling layer of predominantly coarse minerals and a liquid top layer of predominantly sludge having a composition:

Bitumen 4 ~
Minerals 24 %
Water 72 %
This sludge is recycled to the process for mixing with fresh sludge from a tailings pond and with fresh mined oil sands 2~3~1~

ore. Liquid from the set~ling layer may also be recycled to the process as settling proceeds. This use of sludge as process liquid for processing mined oil sands may make it possible to consume and eventually eliminate the accumula-tion of sludge in the the current mined oil sands tailingsponds. The process of the present invention does not re-quire flotation of bitumen in separation cells. It does not require highly dispersed slurries and density differences to achieve separation, as do many other processes in the prior art. It separates mixtures of sludge and mined oil sands without the need for much additional process water. When used in this manner this invention provides an important potential option for eliminating environmen-tal impact from mined oil sands tailings pond sludge.

Bitumen product from a cold water process separating mined oil sands contains 30% bitumen, 12~ minerals and 58%
water. Ten metric tonnes per hour of this product is pro-cessed in a pilot plant using an apparatus similar to Figure2 of the present invention. The separator of the pilot plant is 1.5 meter long, 2.7 meters high and 2.1 meters wide. It uses three spiral mesh wire belts made from type 304 stainless steel. The inside belt is mounted in an in-~5 side compartment and is driven by friction. The driveroller (25) is covered with neoprene rubber and another neo-prene covered roller presses the inside belt against the driven roller. The inside belt is 1.00 meters wide and 2.3 meters long and 1.4 meters of that is immersed in mixture in the inside compartment. The middle belt is 1.00 meters wide, 3.9 meters long and 2.2 meters of that is immersed in mixture outside of the inside compartment. The middle belt is driven by friction. The drive roller ~12) is covered with neoprene rubber and another neoprene covered roller presses the outside belt against the middle belt against the driven roller. The outside belt is 1.00 meters wide, 4.3 meters long and 2.6 meters of that is immersed in mixture 2~33~ ~

outside the inside compartment. The top flight of the out-side belt rests on the top flight of the middle belt. End walls of the separator wall also form the end walls of the inside compartment. These end walls are straight and paral-lel and are l.01 meters apart. The inside of each end wall adjacent to the immersed edges of the inside, middle and outside belts is covered with a self adhesive sheet of ultra high density polyethylene that is 0.3 centimetres thick, leaving a clearance of 0.2 centimetres between each belt edge and each covered end wall. The belts are carefully fabricated to be straight and uniform. Apertures between the spirals of the belt are approximately 0.4 centimetres by 0.6 centimetres in width and length. The inside belt moves at 19 centimetres per second and the middle and outside belts move at 14 centimetres per second.
The feed of lO metric tonnes per hour of bitumen mix-ture, representing approximately 2.5 litres per second is introduced into the inside of the inverted arch of the mid-dle belt. Bitumen separates from that mixture and attaches to the surfaces of the middle belt bottom flight as mixture passes through the apertures. Bitumen depleted mixture flowing into the volume between the middle and outside bot-tom flights next passes through the apertures of the outside bottom flight where additional bitumen sepaxates from that bitumen depleted mixture and a attaches to the surfaces of the outside belt. Bitumen depleted mixture that has passed through apertures of both the middle and the outside belts is removed from the separator as an effluent. Total mixture removed from the separator as an effluent is approximately 8430 kilograms per hour containing 1% bitumen, 10% minerals and 89% water.
Bitumen captured by the middle and outside belts amounts to approximately 5820 kilograms per hour and has a composition of 50% bitumen, 15% minerals and 35% water.
This bitumen is washed from the top flights of the middle and outside belts with approximately 25,000 kilograms per hour of warm circulating water at 50 degrees centigrade and ~332:L~

2,900 kilograms per hour of cold water at 20 degrees centi-grade with the use of nozzles. This circulating water is pumped through a hydrocyclone to produce an underflow and an overflow. The overflow is directed to the nozzles and the underflow from the hydrocyclone is returned to the inlet of the separator to blend with the bitumen mixture feed. This underflow is controlled to maintain the desired level of 1.4 meters of inside belt immersion.
Bitumen washed from the top flights of the middle and outside belts has become highly diluted with water as it flows into the inside of the inverted arch of the inside belt. As this mixture passes through apertures of the bot-tom flight of the inside belt, bitumen adheres to the sur-faces of this belt and is conveyed to the top flight where saturated steam at a pressure of 300 kilo Pascals flows through nozzles to blow this bitumen from the top flight of the inside belt into a receiver. This final bitumen product flows by gravity into containers for storage at a rate of approximately 4480 kilograms per hour and has an approximate composition of 65% bitumen, 9% minerals and 26~ water.
As a result of the process of the invention in this example, a feed of bitumen product from another process, containing approximately 30% bitumen and having a bitumen to mineral ration of about 2.5 has been converted into a bitu-men product containing approximately 65% bitumen with a bi-tumen to mineral ratio of about 7.
Although the invention as has been described is deemed to be that which forms the preferred embodiments thereof, it is recognized that departures may be made therefrom and still be within the scope of the invention which is not limited to the details disclosed but is to be accorded the full scope of the claims so as to include any and all equivalent methods and apparatus. For example, hot or cold air from nozzles or from an air knife, or hot flue gasses may be used in stead, or as well, to asist in the removal of bitumen from the top belt flight surfaces.

Claims

1. A method for the recovery in one apparatus of bitumen and bitumen wetted minerals from one or more mixture(s) of bitumen, water, bitumen wetted minerals and water wetted minerals which method comprises passing through said mixture(s) two or more nested apertured endless belts each belt consisting of a bottom flight at least partly immersed in one of said one or more mixture(s) and a top flight that is not immersed in bitumen, minerals and water mixture, a) wherein bitumen, including some water and some minerals, separates from bitumen, minerals and water mixture and attaches to belt bottom flight surfaces as mixture passes through belt bottom flight apertures causing mixture to become bitumen depleted after which bitumen depleted mixture is removed from said apparatus to disposal or is recirculated or reused, b) wherein belt bottom flight surfaces, with bitumen adhering to these surfaces, emerge from mixture, move upward and revolve to become temporarily top flight surfaces, c) wherein bitumen, including some water and some minerals, falls from said top flight surfaces for further processing into a compartment or into a receiver located under said top flight surfaces after which said surfaces revolve to become temporarily bottom flight surfaces, d) wherein said belts are supported by at least two conveyor supports, at least one of which is revolving and is driven, the top of each support being located above the surface of at least one of said mixture(s), in such manner that each top flight between its supports assumes or approximates a generally horizontal path and each bottom flight between its supports assumes a path that resembles or approximates an inverted arch, e) wherein end walls are provided along each bottom flight adjacent to both immersed edges, f) wherein at least the bottom flights of said nested belts are enclosed in one or more tank(s) or compartment(s) that contain(s) said mixture(s) for separation.

2. A method as in Claim 1 wherein two or more nested belts are used to recover bitumen and bitumen wetted minerals from one mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, wherein said mixture is introduced into the inside of the inverted arch of the innermost of said nested belts, passes through the bottom flight apertures of said belts, wherein bitumen from said mixture adheres to surfaces of said belts and bitumen depleted mixture, mainly consisting of water and water wetted minerals, is removed from the outside of the inverted arch of the outermost of said nested belts.

3. A method as in Claim 1 wherein two or more nested belts are used to recover bitumen and bitumen wetted minerals from one mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, wherein said mixture is introduced from the outside of the inverted arch of the outermost of said nested belts, passes through the bottom flight apertures of said belts, wherein bitumen from said mixture adheres to surfaces of said belts and bitumen depleted mixture, mainly consisting of water and water wetted minerals, is removed from the inside of the inverted arch of the innermost of said nested belts.

4. A method as in Claim 1 wherein two or more nested belts are used to recover bitumen and bitumen wetted minerals from one mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, wherein said mixture is introduced between the inverted arches of two of said nested belts, passes through the bottom flight apertures of said belts, wherein bitumen from said mixture adheres to surfaces of said belts and bitumen depleted mixture, mainly consisting of water and water wetted minerals, is removed from the outside of the inverted arch of the outermost of said nested belts and from the inside of the inverted arch of the innermost of said nested belts.

5. A method as in Claim 1 wherein in one apparatus two or more nested belts are used to recover bitumen and bitumen wetted minerals from mixtures of bitumen, water, bitumen wetted minerals and water wetted minerals, a) wherein a mixture of bitumen, minerals and water is passed through apertures and past surfaces of the inverted arch of one or more nested belt(s) of said two or more nested belts wherein bitumen separates from said mixture adheres to these belt surfaces and bitumen depleted mixture, mainly consisting of water and water wetted minerals, after passing through these belt apertures, is removed from said apparatus, b) wherein said bitumen adhering to said belt surfaces, and containing minerals and water, is conveyed to corresponding top flight(s) of said one or more nested belt(s), is washed from these top flight(s) with water and flows into an inside compartment containing other one or more nested endless belt(s) that nest with the first said one or more nested belt(s), c) wherein water mixture of bitumen and minerals washed from the top flight(s) of said one or more nested belt(s) is passed through apertures and past surfaces of the bottom flight(s) of said other one or more nested belt(s), d) wherein bitumen and bitumen wetted minerals separate from said water mixture and adhere to surfaces of the bottom flight(s) of said other one or more nested belt(s) and bitumen depleted water mixture, mainly consisting of water and water wetted minerals, after passing through the apertures of the bottom flight(s) of said other one or more nested belt(s), is removed from said inside compartment e) wherein bitumen and bitumen wetted minerals captured by surfaces of the bottom flight(s) of said other one or more nested belt(s) are conveyed to the corresponding top flight(s) of said other one or more nested belt(s), f) wherein, bitumen and bitumen wetted minerals fall from the top flight(s) of said other one or more nested belt(s) into a product receiver and wherein these bitumen and bitumen wetted minerals are removed from said product receiver for further processing.

6. A method as in Claim 5 wherein a flow of warm circulating water, exceeding 30 degrees centigrade in temperature, is used to wash bitumen and minerals from the top flight(s) of said one or more nested belt(s) to form a water mixture of bitumen and minerals which is passed through the apertures in the bottom flight(s) of said other one or more nested belt(s) and yields a bitumen depleted water mixture mainly consisting of water and water wetted minerals which depleted mixture is pressurized with a pump and passes through one or more hydrocyclones to remove hydrophilic solids through the underflow of said hydrocyclones, and wherein the overflow of said hydrocyclones is returned to the top flight(s) of said one or more nested belt(s) through jets or nozzles to wash bitumen and minerals from said top flight(s), and wherein water is added to the said warm circulating water to make up for the loss of water through said underflow.

7. A method as in Claim 6 wherein said water added to said warm circulating water is colder than said circulating water, said colder water flowing from nozzles onto the top flight(s) of said one or more nested belt(s) at a location, away from said jets or nozzles of warm circulating water, further along the top flight(s) in the direction of belt movement.

8. A method as in Claim 5 wherein saturated or unsaturated steam under pressure, flowing through nozzles, is used to blow bitumen and bitumen wetted minerals from the top flight(s) of said other one or more nested belt(s) into a product receiver.

9. A method as in Claim 1 wherein one or more of said two or more nested apertured endless belts is a or are flat wire metal belt(s) made from an oleophilic metal or coated with an oleophilic coating.

10. A method as in Claim 1 wherein one or more of said two or more nested apertured endless belts is a or are roller belt(s) made from a multitude of rollers, linkages and cross rods.

11. A method as in Claim 9 or 10 wherein said flat wire metal belt(s) or said roller belt(s) is or are supported by one or more revolving conveyor suport(s) and by at least one driven revolving shaft with sprockets that engage with said belt(s) and drive said belt(s).

12. A method as in Claim 1 wherein one or more of said two or more nested apertured endless belt(s) is a, or are, spiral mesh wire belt(s) made from an oleophilic metal or coated with an oleophilic coating.

13. A method as in Claim 9, 10 or 12 wherein said belt(s) is or are made from type 304 stainless steel.

14. A method as in Claim 1 wherein at least one or more belt(s) are supported by one or more revolving conveyor rollers and by at least one driven revolving conveyor roller that drives said moving endless belt(s) by friction.

15. A method as in Claim 14 wherein one or more additional rollers force said belt(s) against said driven conveyor roller to drive said belt(s) by friction, and wherein said driven roller is covered with rubber and/or with a man made material, to increase friction with said belt(s).

16. A method as in Claim 1 wherein two nested belts are used wherein the outer of said two nested belts is a spiral mesh wire belt and the inner of said two nested belts is a flat wire belt or a roller belt wherein the apertures in the outer belt are smaller than the apertures in the inner belt and wherein the top flight of the outer belt rests on the top flight of the inner belt.

17. A method as in Claim 1 wherein two nested belts are used wherein the outer of said two nested belts is a flat wire belt and the inner of said two nested belts is a flat wire belt or a roller belt wherein the apertures in the outer belt are smaller than the apertures in the inner belt and wherein the top flight of the outer belt rests on the top flight of the inner belt.

18. A method as in Claim 1 wherein two nested belts are used wherein the outer of said two nested belts is a spiral mesh wire belt and the inner of said two belts is a spiral mesh wire belt wherein the apertures in the outer belt are smaller than the apertures in the inner belt and wherein the top flight of the outer belt rests on the top flight of the inner belt.

19. A method as in Claim 1 wherein jets of fluid under pressure are used to remove bitumen water and minerals from one or more top flight(s) into one or more receiver(s) located under said top flights.

20. A method as in Claim 19 wherein said fluid under pressure is di-hydrogen oxide in the form of cold water, warm water, hot water or steam.

21. A method as in Claim 1 wherein the apertures in said two or more nested apertured endless belts are between 0.1 and 20 square centimetres each in area cross section.

22. A method as in Claim 1 wherein the apertures in said two or more nested apertured endless belts are between 0.6 and 6 square centimetres each in area cross section.

23. A method as in Claim 1 wherein the width of said two or more nested apertured endless belts is between 1 and 25 meters and the length of said two or more nested apertured endless belts is between 5 and 100 meters.

24. A method as in Claim 1 wherein the width of said two or more nested apertured endless belts is between 3 and 10 meters and the length of said two or more nested apertured endless belt is between 10 and 30 meters.

25. A method as in Claim 1 wherein one or more guides or rollers are mounted adjacent to the surfaces of the inverted arch(es) of one or several of said two or more nested apertured endless belts in close proximity to said inverted arch(es) to prevent or reduce swinging of said one or several of said belts.

26. A method as in Claim 1 wherein water from nozzles is sprayed onto bitumen adhering to one or more of said bottom flight(s) above the interface of one or more of said mixture(s) to wash off minerals that adhere to the surfaces of said bitumen emerging from said interface.

27. A method as in Claim 1 wherein the bitumen in said one or more mixture(s) has a viscosity between 10,000 and 5,000,000 centipoises and wherein the temperature of said one or more mixture(s) is between zero degrees centigrade and eighty degrees centigrade.

28. A method as in Claim 1 wherein the bitumen in said one or more mixture(s) has a viscosity between 100,000 and 2,000,000 centipoises and wherein the temperature of said one or more mixture(s) is between five degrees centigrade and fifty degrees centigrade.

29. A method as in Claim 1 wherein the contents of one of said one or more mixture(s) is or includes oil sand and water.

30. A method as in Claim 1 wherein the contents of one of said one or more mixture(s) is or includes tailings from a mined oil sands plant.

31. A method as in Claim 1 wherein the contents of one of said one or more mixture(s) is or includes tailings pond sludge from a mined oil sands plant.

32. A method as in Claim 1 wherein one of said one or more mixture(s) is a tumbled and screened mixture containing mined oil sands ore and tailings pond sludge.

33. A method as in Claim 1 wherein one of said one or more mixture(s) is a tumbled and screened mixture containing mined oil sands ore, tailings pond sludge and/or circulating effluent water.

34. A method as in Claim 1 wherein one of said one or more mixture(s) is a bitumen product containing bitumen, minerals and water.

35. A method as in Claim 1 wherein one of said one or more mixture(s) is from an oil well.

36. A method as in Claim 1 wherein one of said one or more mixture(s) contains a mineral ore from a mineral mine and bitumen and water.

37. A method as in Claim 1 wherein one of said one or more mixture(s) contains a mineral ore from a placer deposit and bitumen and water.

38. A method as in Claim 1 wherein said bitumen from said receiver(s) in a subsequent process is diluted with a diluent to separate this product into minerals and a minerals reduced bitumen product.

39. A method as in Claim 1 wherein the speed of at least one of said two or more nested apertured endless belts is controlled automatically with one or more light sources and one or more photocells or photo sensitive devices such that said speed increases as bitumen content of belt apertures increases and such that said speed decreases as bitumen content of belt apertures decreases.

(B) In the case of an apparatus -

40. An apparatus for the separation of bitumen and bitumen wetted minerals from a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, which apparatus comprises:
a) at least one container for containing a mixture of bitumen, water, bitumen wetted minerals and water wetted minerals, b) conveyor supports to mount two or more nested movable apertured oleophilic endless belts supported in such a manner that in operation their paths include top flights that are approximately horizontal and are above the normal level of mixture in said container, and bottom flights that hang in the shape of or approximate the shape of inverted arches , and that extend down to below the said normal level of mixture so that a portion of each bottom flight is immersed in bitumen, water and minerals mixture during operation of the apparatus, whereby in operation bitumen, including some water and minerals, adheres to bottom flight surfaces of said apertured belts as mixture passes through bottom flight apertures, c) means to revolve and drive one or more of said conveyor support(s) whereby in operation said endless belts are revolved and bottom flight belt surfaces and adhering bitumen rise from said mixture and are conveyed temporarily to corresponding top flights.

41. An apparatus as in Claim 40 wherein two or more nested movable apertured oleophilic endless belts are supported in such a manner that their paths include top flights that are approximately horizontal and are above the normal level of mixture in said container, and bottom flights that hang in the shape of or approximate the shape of inverted arches , and that extend down to below the said normal level of mixture so that a portion of each bottom flight is immersed in bitumen, water and minerals mixture during operation of the apparatus, whereby in operation bitumen, including some water and minerals, adheres to bottom flight surfaces of said apertured belts as mixture passes through bottom flight apertures, a) means to revolve and drive one or more of said conveyor support(s) to revolve said endless belts whereby in operation bottom flight belt surfaces and adhering bitumen rise from said mixture and are conveyed temporarily to corresponding top flights, b) one or more receivers located beneath the top flights of said belts to receive bitumen which in operation falls from said top flights,

42. An apparatus as in Claim 41 wherein end walls are provided adjacent to the edges of the endless belts along the normally immersed portions of the bottom flights, to cause flow of mixture through the belt apertures.

43. An apparatus as in Claim 40 or 42 wherein said container for containing said mixture is provided with one or more inlet(s) for admission of bitumen, water and minerals mixture to said container and one or more outlet(s) for removal of bitumen depleted mixture from said container and/or one or more outlet(s) for removal of bitumen product and wherein an inside compartment is provided for keeping one or more belt(s) apart from said two or more belts wherein, in operation, mixture passing through apertures of belt(s) in said inside compartment is kept apart from mixture passing through belt apertures outside of said inside compartment.

44. An apparatus as in Claim 41 or 42 wherein at least one of said endless belts is a flat wire metal belt .

45. An apparatus as in Claim 41 or 42 wherein at least one of said endless belts is a spiral mesh wire belt.

46. An apparatus as in Claim 40, 42 or 44 wherein at least one of said conveyor support(s) is a conveyor shaft mounted in bearings, said shaft having mounted on its surface sprockets with teeth that will engage with a flat wire belt or with a roller, linkage and cross rod belt.

47. An apparatus as in Claim 40 or 42 wherein at least one of said conveyor support(s) is a conveyor roller lagged with rubber and/or with a man made material that can drive a flat wire belt or a a spiral mesh wire belt by friction.

48 An apparatus as in Claim 40 or 42 wherein said endless belts are supported by at least one driven conveyor support and by enough revolving and/or stationary conveyor supports under the top flights of said endless belts to limit the deflection of said top flights to less than 10 percent of the deflection of the corresponding bottom flights.

49. An apparatus as in Claim 41 or 42 wherein said endless belts are supported by at least one driven conveyor support and by enough revolving and/or stationary conveyor supports under the top flights of said endless belts to limit the deflection of said top flights to less than 2 percent of the deflection of the corresponding bottom flights.

50. An apparatus as in Claim 41 or 42 wherein one or more of said endless belts are enclosed so as to retain heat and vapours.

51. An apparatus as in Claim 41 or 42 wherein jets or nozzles are provided adjacent one or more top flight(s) to assist in the removal of bitumen from said top flights during operation

52. An apparatus as in Claim 41 or 42 wherein nozzles are provided adjacent to one or more bottom flight(s) above said normal level of mixture to spray water onto bitumen adhering to bottom flight surfaces during operation to wash hydrophilic minerals from said bitumen after it has emerged above the interface of mixture.

53. An apparatus as in Claim 40 or 41 wherein said means to revolve and drive one or more of said conveyor supports includes one or more electric motor(s) the speed of which is controlled from one or more variable frequency power source(s).

54. An apparatus as in Claim 41 or 53 wherein one or more light sources and one or more photocells or photo sensitive devices are installed to control automatically the speed of at least one of said two or more nested apertured endless belts, which photo cells or photo sensitive devices are connected electrically or electronically such that said speed increases as bitumen content of belt apertures increases and such that said speed decreases as bitumen content of belt apertures decreases.

55. An apparatus as in Claim 41 wherein an air knife is installed above a top flight to remove bitumen from said top flight.

56. An apparatus as in Claim 41 wherein a duct is provided to supply flue gasses to heat a top flight to assist in the removal of bitumen therefrom.