US1389674A - Flotation-machine - Google Patents

Description

L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

Patented Sept. 6, 1921.

4 SHEETS-SHEET w m WWW m w; m x n \N AC. Q m Q N @W Q E V 1\\ Hr v m J J i Q El \w l \w dr N w fimmw M L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

1,389,674. PatentedSept. 6,1921.

4 SHEETS-SHEET 2.

INVENTORS l. 0. 17006;

L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED $251920.

L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

1,389,674. PatentedSept. 6, 1921.

4 SHEETSSHEET 4.

[ir a UNITED STATES PATENT OFFICE.

LEO DANIEL LYONB AND CONRAD FRANCIS HOFF, OF BUTTE, MONTANA.

FLOTATION-MAGHINE.

Application filed Kay 21,

tana, have invented a new and Im roved Flotation-Machine, of which the fol owing is a full, clear, and exact description.

This invention relates to means for recovering valuable minerals from their crushed ores by the flotation process, and has reference moreaparticularly to a machine which is equippe with floating froth cutters, and an automatically controlled weir gate.

As commonly ractised in the recovery of valuable minera s, the ore containing the minerals is crushed to a suitable fineness,

and is introduced into a chamber where it is agitated with water to form a pulp, and a small percentage of oil and acid is added with the introduction of air during the agitation. A froth is formed, as a result, which consists in a large mass of air bubbles which rise to the surface carrying with it the valuable minerals contained in the crushed ore, and leaving behind the worthless gangue. This process isespecially adapted for min erals of'the sulfid type where the preferential action of the air bubbles on the valuable minerals contained in the pulp is especially marked and causes a very complete separation of said valuable minerals from the worthless gangue.

It is a known fact that in order to accomplish the very best separation, it is necessary to remove the froth containing the concentrated minerals, from the spitzkastens practicall as fast as it is formed, since the air bubb es are fragile, and unless quickly re moved will break and drop the valuable minerals back into the pulp. In order to accomplish this, the pulp level in the spitzkastens in the flotation machine 'must' be maintained very close to the froth discharge level. It is diflicult to maintain the pulp 7 level in the 'spitzkastens at such a point where the maximum volume of froth will be skimmed ofi properly, and it is evident that any ofthe pulp level ,in the spitzkastens Specification of Letters Patent.

Patented Sept. 6, 1921 1920. Serial No. 383,229.

above that of the normal operating pulp level will result in the S10 ping of the gen ue material over with t e concentrate froti into the concentrate launder. Special types of mechanical Skimmers have been used to remove the froth as it is formed, but these Skimmers increase the slopping of the gangue material, since when the skimmer paddle strikes the pulp it throws some over into the froth of the concentrate launder. Some machines are provided with a middling launder built parallel to the concentrate launder, and extending the full length of the machine. Aprons are provided from the lips of the spitzkastens to the outer side of the middling launder, which extend the full width of the spitzkastens. When the machine is operating normally, the froth is skimmed off by means of the mechanical skimmer, and discharges over the apron into the concentrate launder; but when slopping occurs, the aprons are removed so that the concentrate froth and the gangue pulp are sent directly to the middling launder which leads to the feed end of the machine. It is evident that the above provision, while it does serve to prevent gangue from slopping into the concentrate launder (at times only however when the operator of a machine is present to remove the necessary aprons) is a poor practice, since the concentrate froth is not sent to the concentrate launder, but is returned through the middling launder to the feed end of the machine to be re-worked. This greatly decreases the efficiency of the machine, since the mineral load in the machine is greatly increased by re-working so much material. Furthermore, when a concentrate is returned to the feed end of the machine, not as complete separation is obtained on re-working, since it is found that the gangue pulp tends to hinder the selective and preferential action of the air bubbles. This is especiall noticed when a roughing machine is use to be followed by a finishing machine reworking the concentrate. When a sloppy, rougher concentrate froth is made, it is possible to make th'm froth fairly clean and free from gangue by excessively banking the cleaner machine used for the fine concentration, but to-excessively bank (deep bed of froth hence low pulp level) will cause the tailing of the machine to have a high percentage of valuable minerals due to the bursting of the air bubbles which allows the minerals to settle into the gangue material. It often happens that when banking is resorted to, the operator is deceived regarding the depth of the froth in the machine, so that the loss of valuable minerals in the tailings of the machine will be excessive.

V In some flotation plants, the flotation feeds vary in volume so that excess occurs at the lip of the first spitzkasten, and within a short period, unless a correction is made, there is an excessive overflow in all the Spitzlrastens of the machine, so that much gangue accomplished by' opening a valve in the tailing spitzkastens.

An object of this invention therefore is to .provide a floating froth cutter at the lip of each spitzkasten which willalways remove a definite depth of concentratev froth, regai'dless of the pulp level in the spitzkasten, which may vary due to variations in the volume of the pulp fed into the first spitz hasten. I

Another object of this invention is to provide a means of by-passing any excessive overflow in any spitzlrasten to the adjacent spit'lzkasten so that the pulp level will be maintained substantially constant. 7

Another object of this invention is to provide an automatic means for raising and lowering the weir gate in the last spitzkasten when variations in. the volume of pulp level will be feed occur, so that the maintained constant.

Another object of this invention is to pro vide means of lay-passing the pulp around one cell when same 18 out of order.

A further ob ect ofthis invention, is to provide a flotation machine which will make a cleaner concentrate, a tailing containing a lower percentageofvaluable niine'als, and which will have a lowerconsumption of oil u o acid or alkali.

A still further object of this invention istofprovide a'inachine which will not require mechanical shimmers, and which will recation, in which it is understood that the drawings illustrate only one form of the invention, and in which- Figure 1 isa' side elevation of the flotation machine with parts broken away to disclose the construction.

Fig. 2 is a plan view -chine. Fig. 3 is a section through. the machine on the line 3-3 of Fig. 1.

' Fig. 4 is a section through the machine on the line 4l4t of Fig. 1. p

1* ,5 is a section through the machine on thelines 5-5of Fig.1. r

Fig. 6 is a transverse sectional view on a of the flotation malarge sale through part of one cell of the flotation machine. Fig. 7 is a section on a large scale througl a cll on the line 7 of Fig. 6.

Fig. 8 is a sectional view on a large scale through one of the removable overflow par titions. i

Fig. 9 is a plan view on a large scale of one of the floating froth cutters.

Fig. 10 is a: sectional view through the a 11 isa diagrainmatical perspective" view of thesystem of operating leverscon froth cutter on the line l0-10 of Fig. 9.

trolling the Weir gate.

Referring to the accompanying drawings by numerals, 10 indicates the front oblique wall of a spitzkastemhaving a second vertical wall 11, and'side walls 12. These walls 7 of the cell form what is ordinarily called a spitzkasten, and the oblique wall 10 has a lip 13 at its upper edge, whose purpose will be hereinafter described. v

A bottom 14 is formed in the spitzkasten, and a: false bottom 15 is secured between the walls thereof at some distance above the bottom 14. A number of the spitzkasten's' are joined together in series, so that the side walls 12 of one also form the side walls for adjacent spitzkastens.

A rectangular agitating chamber 16 having a bottom 17 is secured to the side wall empties into saidagitating chamber 16 at a point nearits top. The agitating chamber 16' is lined at its bottom with a rectangular box 19, and a port 20 is provided in the wall 11 and the adjacent wall of the'box 19, which opens into the spitzkasten. The agitating 11 of each spitzkasten, and an intake pipe 18 chamber 16 is supported by any suitable V frame-work 21, and. vertical standards 22 are also supported by said frame-worlnsaid standards being provided at their upper;

ends with ayoke 23 which may preferably be of cast metal, and which supports a horizontal shaft 2 1 extending across all the 7 mixed with air.

aire on thepulp 44.

' la r to the propeller of a power driven boat.

. each of the vertical shafts by beveled gears not shown.

As the finely pulverized ore, mixed with water, a small percentage of oil and acid to form a pnlpfis introduced throuph the pipe 18, it is agitaterhgyl the impel er 26 and downwardly a ja'cent theport 20 so as to deflect the aerated ulp from the chamber 16 to thebottom of the spitzkasten, so as to leave the froth which rises tothe surface of the pulp into the spitzkasten, undisturbed.

A concentrate launder 28 extends along each of the s itzkastens, adjacent the lips 13,

and slopes o liquely to the delivery end of the machine, where it empties into a pipe 29 which receives the concentrate froth containing thewaluable minerals. The launder ,-.28 hasan 0utside-wall30, and an inside wall 31, which also forms the wall of, the middling launder 32, having an inside wall 33. The middling launder 32 slopes obliquely from each end of the machine to'the center thereof, where it empties into a pipe 34 extending. below the machine, and t0 the other side, where it'is connected to a bucket elevator 35 delivering to a pipe 36, which is connected to the pipe 18. The insidewall' down-take pipes 38 are connected to the launder 37 and'to a compartment 39 formed by the false bottom 15. An apron 40 extends obliquely from the wall 33 to the wall 31, and a plurality of slots 41 are formed in 1 the wall 33fadjabent said apron so as to connect thelalinder-37 with the launder 32.

The froth which forms on top of the pulp in the spitakastenis composed of concentrate frp'th 42, belowwhich is asub-froth 43 sup- The concentrate frotlt 42 contains most of the valuable minerals (usually iii-the sulfid form) with very little gaiigue material. The top of the .wal 33'is spaced apart from the lip l3 of the spitzkiasten, and a cutting apron 45 is hinged on abrack'et 46, which is secured to the wall 33.atl.'the junction of the apron 40 with said w .33.

eapron 45 has horizontal supports 47 to are attached a plurality (preferably two .(in number of metallic hollow floats 48, which are adjustably secured theretqby means of nuts 49 so that the position of the supports 47 relative to said e aerated pulp flows through the port 20 into the spitz kasten, where it rises 'on the false bottom 15 to thelevel of the li 13. A "shield, 27 extends floats may be varied Thus, as seen in Fig. 6 the floats 48 will be so adjusted and the supports will be so positioned that the apron 45 will act as a cutter to separate the concentrate froth from the sub-froth so that the concentrate froth will pass over the apron 45 into the concentrate launder 28, while the sub-froth 43 will pass between the walls 33 and 10 into the first middling launder 37.

The Sub-froth will flow from the first middling launder 37 through the downtako pipe 38 into the compartment 39. If desired, a perforated pipe 37 (Fig. 4) may be positioned in the launder 37 which is adapted to direct a spray of water on the subfroth in said launder so that said subfroth will be broken up. If the flow of the sub-froth 43 becomes too great to be handled by the down-take pipe 38 in spite of the water spray, the excess will flow through the slots 41 into the middling launder 32, which will conduct it through the pipe 34, the bucket elevator 35, the pipe 36 and the pipe 18 back into the agitating chamber 16 of the first cell. The pipe 50 connects the chamber 39 with the chamber 16, and the up or end of said pipe is positioned directly un er the impeller 26 so that when said impeller is rotated in the proper direction it will draw the material from the compartment 39 into the chamber 16 where it will be further aerated.

A weir 51 is provided in each of the spitzkastens (Fig. 1) and is connected at. its lower edge to the false bottom 15, while its upper edge is positioned somewhat below the lip 13 of the spitzkasten.- The concentrate froth is prevented from flowing over the weir 51 by a shield 52 which is connected to the wall 12' of the spitzkasten by endwal'ls 53. The pulp flowing over the weir 51 is substantially free from air bubbles, since it has been taken from the bottom of the spitzkasten, and said pulp is delivered into the compartment 39 where it is combined with the products entering said compartment 39 through the down-take pipes 38.

The launder 37 is divided into compart ments, one compartment for each spitzkasten, by fixed partitions 54 into which is inserted a rectangular removable partition 55 so that the overflow of sub-froth together with a small portion of gangue pulp from each lip 13 normally flows into its respective compartment formed by the partitions 54 and 55, and is transferred to the compartment 39 by each down-take pipe 38. However it sometimes happens that one down-take pipe will become clogged up, or one cell will become out of order so that, in this case the removable partition 55 is removed so that the pulp is by-passed around the cell which is out of order, to the compartment in the launder 37 ofthe ad jacent cell. The coarser particles contained in the pulp will settle to the false bottom 15, and will not flow over the weir 51, so

that a sand hole 56 is provided in thefalse bottom 15, to allow these coarser particles to flowcinto the compartment 39,.where they will combine with the other products introduced into said compartment.

It often happens in flotation plants, that the volume of'pulp varies from time to time, sothatan excessive overflow over the lip 13 in the first cell will soon cause a slope ping over the lips 13 of the remaining cells,

unless provision is made for lowering the head inthe remaining cells so as to relieve the overflow conditions.

we provide a weir gate 57 at the top of a as p r 1 65 isconnected to this last mentioned arm,

small portion, of the gangue pulp flowingv ther end.

For this purpose weir 58 in the last cell. This weir gate is pivoted at one end to the wall 11 of the spitzkasten, by means of a hinge 59 and its position is controlled by a rod 60 pivoted to its The rod 60 is connected to one arm of a bell crank lever 61 pivoted onthe framework of the machine, and the other arm of said lever is connected by a rod 62 to one arm of a bell crank lever 63 also pivoted on the frame-work of the machine. A spring 64: is connected to the other arm of the bell crank lever63 at one end, and is secured to the frame-work of the machine at the other end, so that normally the weir gate 57 is in its lowermost position. In order to actuate the bell crank lever 63, a cable or rod and extends to the feed end of the machine, where it is connected to one arm of a bell crank lever 66, pivoted to the machine. A rod 67 connects the other arm of the bell crank lever 66 to one arm of the bell crank lever 68, and the other arm of the lever 68 is connected by a rod 69 to a triangular shaped box 70 pivotally mounted by means of a pin 71 to the walls 10 and 33 ofthe first cell, so as to be positioned approximately in the, path of the sub-froth and a small portion of gangue pulp which flows downwardly into the launder 37 i This triangular shaped box 70 is open at the top, and is provided at its lowermost corner with a port 72. This port 72 has a definite size, so that the sub-froth and a into said box 70 will drain out atia predeterniined rate of speed. However, when the flow of sub-froth and gangue-pulp becomes excessive, the box 70 will fill with material since the. port 72 will not then be 1 suflicient to drain the box, so that saidbox will move about its pivot 71 thusactuating the system'of levers and links, thus causing the weir gate 57 to be raised. When the weir gatej57 is thus raised a portion of the pulp in the last cell will flow out under the gate so as to lower the head in the last cell, thus causing the head to lower in all the other cellsso as to relieve the overflow con ditions.

When the pulp thus flows out under the weir gate it flows downwardly into the com- 73, which conducts away the uselessgangue material. A false bottom 15 inthe last cell is provided with a pivotally mounted valve 74 to which is connected a control rod 75,

'partment 39 of the lastcell, and then flows out of said compartment through a tail race and the opening in said valve maybe ac-" curately controlled by means of an adjust-V ing Wheel 76 threaded to receive the end of the rod 7 5,'and mounted on. a bracket 77 secured to the machine. The flow of the and is returned to the feed end of the machine. p r

In operation, the pulp which consists of crushed ore, water, and small percentages.

of oil and acid, is introduced into the agigangue material past the valve 74 may thus tating chamber 16 on the first cell through the pipe 18, and is thoroughly aeratedand agitated by the impeller 26. The aerated pulp flows out through the port 20 into the spltzkasten and is deflected downwardly toward the false bottom 15 of said spitzkasten by the shield 27. The air bubblescontain ing the valuable minerals rise tothe surface, and form a concentrate froth 42', which is supported bythe sub-froth 43, in turn supported by the pulp 44. The coarser par ticles in the pulp, settle to the bottom of i the spitzkasten and flow through the hole 56 into the false bottom 15,- into the compartment 39. The major part of the pulp admitted to the spitzkastens overflowsthe weir 51, and is combined with the other material in the compartment 39. The froth,

sub-froth and a small portion of the gangue pulp overflow the lip 13 of the spitzkasten where the aproncutter 45 cuts the concen- 28, while the latter flows into the first middling launder 37. This apron cutter 45 is 'trate froth from the sub-froth so that the" former flows into the concentrate launder maintained in a definite position relative to the froths 42 and 4:3 by the float 48 which floats on the surface of the pulp 44 so that a uniform cutting of the concentrate froth dling launder 37 kastens.

The sub-froth flowing into the first midassesthrough the downtake pipe 38 into t e compartment 39, where it joins the other products from the sand hole 56and the weir 51. The products combined in the compartment 39 are drawn up through the pipe 50 into the agitating chamber 16 of the next cell by the impeller in that compartment, where it is again aerated and goes through the cycle of operations described in the first cell. The worthless gangue material which collects in the com artment 39 of the last cell, flows out of t e machine through the tail race 73, while the concentrate froth flows out of the concentrate launder 28 through the pipe 29, after which it is treated further to recover the valuable minerals.

If the pulp fed to the first agitating chamber varies involume from time to time,

and an excessive overflow occurs at the lip .13 of the first lpitzkasten, the overflow fills throu h the up the tria ar shaped tank drained by the port which actuates the system of levers and links illustrated in Fig. 11, so that the weir gate 57 in the last cell is raised, thus causing pulp to flow out of the last cell under said weir gate, where it goes with the worthless gangue to the tail race 73. 'If the overflow in the first middling launder 37 is so great that it cannot be handled by the down-take pi 38, the excess overflow flows 52a 41 into the middling launder 3 whichconducts the overflow through the pipe 34,, the elevator 35, the pipe 36 and the pipe 18,..baok into the agitating chamber of the first cellof the machine. In case this method of handling the overflow is not sufficient, the excess flows over the removable partition 55 into the first middling launder compartment of the next cell. If any of the down-take pipes or other part of the cell become out of order or plugged up, the removable partition 55 may be removed so that the excess pulp is by-passed around the cell which is out of order to the next cell.

A flotation machine is thus provided in which a definite depth of concentrate froth is removed atall times regardless of the pulp level in the spitzkasten, which may vary with variations in the volume of the pulp fed into the first spitzkasten. The machine is also provided with means for automatically equalizing and regulating the flow of pulp through the several cells so that the pulp level will be maintained substantially constant. If one cell becomes out of order, the pulp may be easily by-passed around this cell to the next cell in the series. All mechanically operated Skimmers have been eliminated from the machine and a fewer number of flotation cells are necessar to produce a given so aration of minera s from the gangue. t may be desirable to use a mechanical type of slow revolving skimmers in some cases which will be positioned near the center of the spitzkastens of the machine, said skimmers being adapted to further increase the discharge of concentrate froth over the froth cutter. The machine described and illustrated will make a cleaner concentrate, a tailing containing a lower percentage of valuable minerals, and will have a lower consumption of oil, acid or alkali.

We would state in conclusion that while the illustrated example constitutes a practical embodiment of our invention, we do not limit ourselves precisely to the details herein illustrated, since manifestly the same can be considerably varied without departing from the spirit of the invention, as defined in the appended claims.

Having thus described our invention we claim as new and desire to secure by Letters Patent:

1. In a flotation machine rovided with a container, having an over ow lip, and a movably and automatically operated member associated with said container for uniformly separating the concentrate froth from the sub-froth, as said froths flow over said li regardless of the level of the pulp in said container.

2. A flotation machine provided with a container having an overflow lip, floating cutting means associated with said container adapted to separate a uniform depth of concentrate froth from the sub-froth, as said froths flow over said lip, regardless of the level of the pulp in said container.

3. In a flotation machine, a plurality of containers arranged in series, and means associated with the first said containers adapted to release a quantity of pulp from the last of said containers when an excessive supply of pulp is introduced into the first of said containers, so that the pulp level in said container is maintained substantially constant.

4. In a flotation machine, a plurality of containers arranged in series, a pivotally mounted weir gate associated with the last container in said series, and means associated with the first container for moving said weir gate when an excessive quantity of pulp is introduced into the first container, so that the pulp level in said containers is maintained substantially constant.

5. A device, as described in claim 4, characterized by a pivotally mounted box associated with the first of said containers, said box being so positioned as to receive an excessive flow of material introduced into said first container, there being a port formed substantially constant.

adjacent the bottom ofsaid box adapted to I gate adapted to actuate said gate when saidv box is moved about its pivot, so that the pulp level in the containers is maintalned 6. in a flotation machine a' luralit of containers arranged in series, each container being provided with an overflow lip, means associated with each container adapted to aerate and agitate the pulp, and introduce "d aerated pulp into said containers, a enti'a'te launder 130Sil310118 l1011g11311d1- naliy of said containers adapted to receive the concentrate froth delivered from each container, aiirst middling launder adapted to receive the sub-froth and a portion of gangue pulp, delivered from the lip of said.

with each container adapted to allow the overflow of pulp therefrom, and means for combining said pulp overflowing said weir and. said sub-froth overflowing "the lip of' said. containers and transferring said pulp and said sub-froth from one container to an adjacent container in the said series.

.7. A device as described in claim 6, char-' acterized by means for separating a uniform depth of said concentrate froth from said sub-froth flowing over the lip of each conhaving an overflow edge, and a pivoted and automatically controlled member at said cdgeflfor separating the concentrate froth" tainer, regardless of the level of the pulp in each c'ontalner.

8. A device as described in claim 6, char- 7 acterized by means for Icy-passing the pulp around a container in said series, when said container is out of order.

9. A device as described in claim 6, charedge.

- ase acterized by a movable weir gate, associated with the last container in said series, and

means associated with tliefirst container insaid series adapted to actuate the said weir gate when an excessive quantity'ofpulp is introduced into the first container of said series, so that the pulplevel in said container will be maintained substantially constant; I 7

10. In a flotation machine, a container provided witha lip, means for introducing an aerated and agitated pulp into said container so that a concentrate froth and a. sub-froth are formed on the surface of sand pulp, means for causing the pulp to flow from. said container, a cutter apron pivotally associated with said container, and a floating member associated with said'cutter apron adapted to float on the surface of said pulp, and maintain one edge of said cutter sition that a uniform depth of concentrate froth will be separated'from the sub-froth regardless of thelevel of pulp in said containeia 11. A device asdescribed in claim 10,

characterized by means for combiningthe pul flowing from said vcontainers with the sub-froth flowing over the lip of said containers and transferring said combined pulp and froth to an adjacent container. j

12. A device as described in claim 10, characterized by a fals bottom positioned in -said containers, means for combining said sub-froth with said pulp, and means for transferring said combined pulp. and subfroth to adjacent'containers.'

13.1n a flotation machine, a container from the sub-froth as they flow over said LEO DANIEL LYONS. CONRAD FRANCIS HOFF.

apron above said pulp surface in such a po-

Images