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CA1108067A - Apparatus for the selection of grained solids from solid-containing turbid liquids - Google Patents

Apparatus for the selection of grained solids from solid-containing turbid liquids

Info

Publication number
CA1108067A
CA1108067A CA267,530A CA267530A CA1108067A CA 1108067 A CA1108067 A CA 1108067A CA 267530 A CA267530 A CA 267530A CA 1108067 A CA1108067 A CA 1108067A
Authority
CA
Canada
Prior art keywords
plates
packs
sediment
liquid
tank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA267,530A
Other languages
French (fr)
Inventor
Wolfgang Schlitter
Peter Hausdorfer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TRANSROPA Ets
Original Assignee
TRANSROPA Ets
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from ZA757717A external-priority patent/ZA757717B/en
Application filed by TRANSROPA Ets filed Critical TRANSROPA Ets
Application granted granted Critical
Publication of CA1108067A publication Critical patent/CA1108067A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D21/00Separation of suspended solid particles from liquids by sedimentation
    • B01D21/02Settling tanks with single outlets for the separated liquid
    • B01D21/04Settling tanks with single outlets for the separated liquid with moving scrapers
    • B01D21/06Settling tanks with single outlets for the separated liquid with moving scrapers with rotating scrapers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D21/00Separation of suspended solid particles from liquids by sedimentation
    • B01D21/0039Settling tanks provided with contact surfaces, e.g. baffles, particles
    • B01D21/0045Plurality of essentially parallel plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D21/00Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30Control equipment
    • B01D21/32Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Treatment Of Sludge (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

An apparatus for the separation of particulate mineral solids fron ore-bearing liquid and, in particular, for the separ-ation of finely ground ore from ore-containing diluted muds.
known round thickeners have large surface areas and require expen-sive foundations and a highly stable construction. Further, in known lamella thickeners, high solid concentrations of sediment cannot be obtained. The present invention provides an apparatus by means of which solid particles can be extracted from a turbid liquid, the apparatus having a high volumetric efficiency, while achieving high solid concentrations of the sedimentary materials.
The apparatus comprises a settling tank having an overflow weir, and at least one pack of inclined, preferably parallel, plates, arranged between the overflow weir and the location where turbid water is introduced into the settling tank. Sediment accumulates on the inclined plates and is discharged therefrom by gravity to-ward the bottom of the tank. Means are provided below the plates to move the sediment to a discharge location in the bottom of the tank.

Description

~ ~l$8~

This invention relates to an apparatus for -the separa-tion of particula~e mineral solids from solid-bearing turbid li~tuids and, more particularly, but not exclusively, for -the sep-aration of fineLy ground ore from ore-containing diluted muds.
The aim o~ such sepa~ation may be either -the obtaining of as much water as possible for re-use or disposal into a sewage system, or the obtaining of a concentrated mud, -the moisture content of which is as low as possible, that is, having a solid material content which is as high as possible so as to permit re-use thereof or LO disposal thereof.
` To date, installation-free settling tanks, commonly re-erred to as thickeners or round -thickeners, have been used -to carry out the separation re~erred to above. l'he so-called rounded thickeners comprise a cylindrical se-ttling tan]c having a rotatable device mounted in the botto~ of the tank and adapted to propel solid materials which have settled at the bottom of the tank to the center of the bottom of the tank, from where it can be dis-charged from the tank. Such thickeners allow for long re-tention of sediment and enable the sediment to reach satisfactory solid ~0 concentrations. While this is an advantage of such ]cnown thic]c-eneL-s, the same have the disadvantage of a large surface area, necessitating sound :Eoundations and a sound mechanical structure.
Further, the ratio of concentration per unit of surface area is ~uite low and, when the tank is used in areas ~here the cl.imate is hot, dry or windy, excessive evaporation of the liquid in the tank occurs.
The so-called lamella thickener tends to overcome the above disadvantages by having built therein a plurali-ty of inclined plates in the sedimentary space, thereby providing a larger set-tling area in the tank. Thus, while the sedimentary space is les-ser, the effective dura-tion of -the mud in the tank is reduced, whereby high solid concentrations of a sediment, as ob-tained in the round -thic]cener, cannot be obtained with -this appara-tus.
The present invention proposes to provide an apparatus for separating particulate mineral solids from -the turbid liquid, the apparatus havin~ a high volumetric efficiency, while achievlng high solid concentrations in the mud which is separated from -the liquid. This is achieved according to the present invention by providing an apparatus comprising a settling tank having an over-flow weir. The settling tank has at l.east one pack of inclined, preferably parallel, plates, the plates being arranged between 1~ the overflow weir and the location where the turbid water is intro-duced into the settling tank. The arrangement of the pack of plates is such that sediment accumulated on the plates is allowed to discharge under the action of gravity toward the bo-ttom of -the tank. Means are provided below the pack of plates to move the sediment accumulating on the bottom of the tank to a discharge location located in the bottom of the tank.
According to a preferred embodiment of this invention, the tank has a cylindrical shape, the bottom being conical or conoidal, the center of the bottom being deepened in order to ~0 receive sediment therein. -~
The pack of inclined plates occupy a ring-shaped posi-tion about the center of the settling tank and are arranged rela-tive to each other in such a manner that no liquid can flow be-tween two adjacent packs of plates. The sides of the pac]cs can be closed to prevent lateral in-flow or out-flow of liquid relative to the pack of plates. Additionally, the pack of plates can be formed so as to jOill each other laterally without leaving any interspace through which liquid may flow without -first flowing through the pack of inclined pla-tes.
To ensure the flow of turbid liquid through the lamella pack, one embodiment of the present invention utilizes baffle plates arranged about the center of the set-tling -tank. The loca-\

tion and positioning of the baffle plates is such as to direct the flow of turbid liquid into the lamella set. In one arrange-ment of the baffle plates, the same are positioned beneath the lam~lla pack in order to direct -the flow of turbid liquid into the pack of plates.
A means for transporting sediment along the bottom of the tank to a suitable discharge point can comprise a raking device, situated at the bottom of the tank, the device being driven by a mechanism located at the center or on the periphery 1~ o~ the settling ~ank.
According to one embodiment of the present inven-tion, the density of the sediment being discharged and/or the depth of the mud in the settling tank is measured, the measured values being used to control the amount of mud discharged from the set-tling tank per unit of time and/or the speed of the means trans-porting the sediment to the discharge point.
In one aspect of the present invention, there is provided an apparatus for separating grained solids from solid-bearing turbid liquids, the apparatus comprising a settling tank having an overflow weir and packs of plates, said plates being inclined to the vertical plane, together with a raking mechanism for directing the sediment toward a discharge opening, characterized in that said packs of inclined plates are arranged tightly adjacent one to the other, the surfaces of the packs runn1nc stantially vertically and facing the fluid coming sweeping along so that passing through of the fluid between two contiguous packs is prevented and whereby the inclined plates of each pack are in the main aligned with the direction of the flow of the fluid~

In a further aspect of the present inventio~ there is provided a method of withdrawing the sediment from an apparatus for separating grained solids from solid - bearing turbid liquids, the apparatus being of the type comprising a settling tank having an overflow weir and packs of plates, the plates being inclined to the vertical plane, together with a raking mechanism ~or directing the sediment toward a discharge opening, characterized in that at least one value is selected from a plurality of factors comprising the density of the removed sedi~ent and the height of the sediment in the bottom of the settling tank, the value being used for at least one of a plurality of conditions, com~rising control of the mass of sediment withdrawn per time unit and the velocity of the device to direct sediment toward the dis-charge opening.
The invention will now be described with reference to the accompanying drawings which show a preferred form thereof and wherein:
Figure 1 is a plan view of one embodiment of the apparatus according to the present invention' Figure 2 is a vertical section taken along the line a-a of Figure 1, Figure 3 is a side view of a pack of plates, look-ing along the lines b-b of F~gure l; and Figure 4 is a vertical section taken along the line c-c of Figure 1.
~ cylindrical tank 1 having a conoidal bottom 2 and a central discharge 3 is mounted on suitable foundations, not illustrated in the drawings. An over~low weir 4 extends along the free edge of the tank 1.
A raking device 5 is mounted on the bottom of the tank 1 -3a-~ .
-on a central bearing 6. The raking device has an arm 7 extending to an upper edge of the tank wall, at which location is is con-nected to a drivin~ motor 8 mounted on rails 9. The rails 9 ex-tend around the upper edge of the tan]c, and motor ~ drives the rotational motion of the raking mechanism 5. The raking mechan-ism is equipped with raking plates 10 which engage the bottom of the tank 1 and which, during rotational movement of the raking mechanism 5, touch the bottom of the tank and transport the solid materials which have settled out toward the center of the bottom
2 and into the mud discharge 3.
Packs 11 of inclined plates 12 are circumferentially arranged about the center of the tank 1. The packs are in con-tact with each other in order to prevent a through-flow of liquid between adjacent packs. The inclined plates 12 are arranged in such a manner that solid materials settle out on them, the settled solid materials being led by the direction of inclination of the plate 12 so as to fall due to gravity toward the bottom of the tank, from whence the settled materials are directed by the raking mechanism 5 to the central discharge 3.
Each pack 11 is supported by a grate 14, the grate 14 itself being supported by a series of beams 15. The beams 15 are suspended by means of connecting rods 16, the upper ends of the rods 16 being suspended from radial arms 17. The radial arms 17 are secured between a pull ring 18 and a pressure ring 19, -the pressure ring 19 being supported by a series of columns 20. Cross-beams 21 extend between the radial arms 17, the cross-beams 21 being provided to withstand the pushing and pulling forces which, otherwise, are radially directed.
In the embodiment of the invention described herein, the ore-bearing water is fed into the center of the tank 1. l~eans are provided for insuring that at least a portion of such water will pass through the packs 11 béfore reaching the over-flow weir ,- :: . :

4. l~ese means may comprise suitable baffles 22 mounted around the center of the tank and adapted to direct water dischar~ed into the center of the tank towards the packs. Similar baffles 23 are mounted beneath the packs 11 for the same purpose.
The sides 24 of the packs 11 are closed by means of plates 25 to prevent water entering the packs from passing out the sides 24 thereof. The plates 25 need not be fixed to the packs 11, but can simply be suspended along the sides.
A space of at least 300 mm is provided between the outer 1~ edges of the plates 25 and the inner surface of the external wall of the tank 1. After the water has passed through the pack 11, it flows upwardly to the overflow weir 4. In this way, it is pos-sible to ensure that the turbid liquid will flow through the packs 11, and in a radial direction.
The structure described above for supporting the packs 11 may also be used to support a roof (not shown) which protects the apparatus, and prevents excessive evaporation of water from the tank.
In operation, ore-bearing water is fed into the center ~0 of the tank 1. The baffle plates 22 and 23 direct the turbid liq-uid into the packs 11, ensuring that most of the liquid flows throu~h the packs 11 before reaching the overflow weir 4. Sedi-mentation occuring on the plates 12 is eventually discharged there-from due to the downward inclination of the plates and falls to the bottom of the tank due to gravity. Raking plates 10 of the raking mechanism 5 catch the sediment on the bottom of the tank and direct it to -the discharge point 3, from which location the sediment is removed from the tank 1. As noted abave, the speed of the raking mechanism 5 may be controlled as a function of the density of the sediment taken at a suitable poin-t in the tank 1.
The apparatus according to the present invention may be equipped wi-th various other devices without, in any way, departing from the essence of the present invention. Thus the embodiment described above is not intended to limi-t the scope of this inven-tion. For example, in the case of embodiments of the apparatus having smaller dimensions, pac~s 11 may be arranged in parallel, rather than radial, so that the in-flow of the ore-bearing water will take place at one side of the tank, and the overflow weir need not extend about the circumference of the tank, but rather will be situated on a portion of the circumference of the tank op-posite to the in-flow. Similarly, packs 11 could have a wedge-shaped form in plan view, rather than a rectangular cross-section, such that no free interspace remains between adjacent packs. In such a case, the plates 12 will no longer be parallel, but rather will be spaced more closely together adjacent the center of the tank and farther apart adjacent the exterior wall of the -tank~
Furthermore, in the case of increased distances between the plates at locations farther from the center of the tank, one could install additional plates of shorter length, these latter plates being situated between the longer plates which extend from adjacent the center of the tank to locations adjacent the exterior wall of the tank.

Claims (7)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-
1. An apparatus for separating grained solids from solid-bearing turbid liquids, the apparatus comprising a settling tank having an overflow weir and packs of plates, said plates being inclined to the vertical plane, together with a raking mechanism for directing the sediment toward a discharge opening, characterized in that said packs of inclined plates are arranged tightly adjacent one to the other, the surfaces of the packs running substantially vertically and facing the fluid coming sweeping along so that passing through of the fluid between two con-tiguous packs is prevented and whereby the inclined plates of each pack are in the main aligned with the direction of the flow of the fluid.
2. An apparatus according to claim 1 wherein each pack of inclined plates is sealed with plates arranged at the sides of each pack running in the main parallel to the direction of the flow of the liquid.
3. An apparatus according to claim 1 wherein in front of the packs viewed in the direction of the flow of the liquid and underneath the packs, baffle plates are arranged to direct the liquid into the packs.
4. An apparatus according to claim 2 wherein in front of the packs viewed in the direction of the flow of the liquid and underneath the packs, baffle plates are arranged to direct the liquid into the packs.
5. An apparatus according to claims 1 to 3, wherein a gap between the wall of the settling tank and the face of each pack turned off from the flow of the liquid is provided to permit the liquid to flow to said overflow weir.
6. An apparatus according to claim 4, wherein a gap between the wall of the settling tank and the face of each pack turned off from the flow of the liquid is provided to permit the liquid to flow to said overflow weir.
7. A method of withdrawing the sediment from an apparatus for separating grained solids from solid bearing turbid liquids, the apparatus being of the type comprising a settling tank having an overflow weir and packs of plates, the plates being inclined to the vertical plane, together with a raking mechanism for directing the sediment toward a discharge opening, characterized in that at least one value is selected from a plurality of factors comprising the density of the removed sediment and the height of the sediment in the bottom of the settling tank, the value being used for at least one of a plurality of conditions, comprising control of the mass of sediment withdrawn per time unit and the velocity of the device to direct sediment toward the discharge opening.
CA267,530A 1975-12-10 1976-12-09 Apparatus for the selection of grained solids from solid-containing turbid liquids Expired CA1108067A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
ZA757717A ZA757717B (en) 1975-12-10 1975-12-10 Apparatus for the separation of particulate mineral solids from mineral-bearing liquids
ZA75/7717 1975-12-10
ATA760/76 1976-02-03
AT76076A AT352650B (en) 1975-12-10 1976-02-03 DEVICE FOR SEPARATING GRAINY SOLIDS FROM SOLIDS CONTAINING SOLIDS

Publications (1)

Publication Number Publication Date
CA1108067A true CA1108067A (en) 1981-09-01

Family

ID=25593843

Family Applications (1)

Application Number Title Priority Date Filing Date
CA267,530A Expired CA1108067A (en) 1975-12-10 1976-12-09 Apparatus for the selection of grained solids from solid-containing turbid liquids

Country Status (5)

Country Link
AU (1) AU510128B2 (en)
BR (1) BR7608280A (en)
CA (1) CA1108067A (en)
FR (1) FR2334396A1 (en)
MX (1) MX145301A (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2400939A1 (en) * 1977-08-23 1979-03-23 Fives Cail Babcock Compact gravity settlement clarifier partic. for sugar juice - uses annular baffle elements providing zigzag decanting passages
FR2472943A1 (en) * 1980-01-07 1981-07-10 Inst Vodnykh Floating decanter with tubular risers to clarify river water etc. - pumps water ashore from collecting tank above risers
AU635337B2 (en) * 1990-10-03 1993-03-18 Yakutsky Nauchno-Issledovatelsky I Proektny Institut Almazodobyvajuschei Promyshlennosti Apparatus for clarification of industrial sewage
AUPS119202A0 (en) * 2002-03-19 2002-04-18 Outokumpu Oyj Pulp stabilisation apparatus for a thickener
AU2003208185B2 (en) * 2002-03-19 2008-05-22 Metso Outotec Finland Oy Pulp stabilisation apparatus for a thickener

Also Published As

Publication number Publication date
FR2334396A1 (en) 1977-07-08
AU510128B2 (en) 1980-06-12
MX145301A (en) 1982-01-25
AU2042676A (en) 1978-06-15
FR2334396B1 (en) 1982-12-03
BR7608280A (en) 1977-11-29

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