US2609097A - Flotation machine - Google Patents

Description

P 1952 R. DERING I 2,609,097

FLOTATION MACHINE Filed May .12, 1949 2 SHEETSSHEET l IN V EN TOR.

ROGER DER/N6, Q

A fro/EM! 15.

Sept. 2, 1952 R. DERING FLOTATION MACHINE 2 SHEETS-SHEET 2 Filed May 12 1949 ROGER DER/N6,

Patented Sept. 2,

' UNITED STATES PATENT OFF-ICE FLOTATION MACHINE '7 Roger Dering; Salt Lake City, Utah, assignor to Combined Metals .Reduction Company, Salt Lake (Jity. Utah, acorporation *of Utah Applicati0nMay- ,12, 1949,SerialNo. 92,868

' 7 Claims. (01. 209- 169 1 l a This invention relates to flotation machines, extensively-employed for theseparation :of valuable constituents irom ores or other materialsl:

The earl: of notation usually involves both the aeration and agitation of a -so-cal1ed ",pulpj which is .aliquid suspension of finely ground'material containing'the valuable constituents to be recovered. Chemical reagents designed to produce a rroth andi to aid theiroth in retaining valuable particlesadhering :thereto become l'part .of :the pulpinthefflotation procedure. The'iroth which carries the valuable concentrates is recovered as the end productvof the operation.

Flotation machines "ascustomarily constructed .provide -tor :.aeratidn :and agitation of thepulp, in common, within a lsinglelchamber, and lcarry out both operations simultaneously by'thesame impeller.

'In-accordanceiwith.thepresenti-invention,:however, :aeration is accomplished. in one chamber :by an impeller especially designed for aeration'zpurrposespandi agitation of the-aerated pulpziscarried out .in .a second chamber by a second impeller. Both-chambers and both impellersareipart:of the tgeneral flotation machine (structure, :and the aerated pulp ;passes into the zagitation .cl'hamher by way of the second or agitation impeller. :Pro- -visionds made for controlledzrecirculatiomofipulp irom the agitation \chamber aback -.through- -the aeration-chamber.

Principal aobjects-iof I the inventionsare:

To provide 'a iflotation .fmachineiihavingia .hig h operative efilciency, -simplicity -.of construction, and-economy of floonspacecoccupied. Toiprovide'isuelr a machine which willirequire Iew repalrs-andrwill'rhave a;long:operating.zzlife.

Further objects, and features of theiiinvention' :will :become :evident asithmdescription proceeds with respect to :that presently preferred specific construction illustrated in :the accompanying drawings by way of-wexempllfyingi the novelieontsdnwolved rather than "by way :of:limitation. .dzheifirawingsz'. I l-nzep"esentswafdragmentary .top .planiview alaankotiiiptatiomcells -.comprising-a series of themac'hines; ot the invention, the v-first machine e .eel1 being shownvin ntirety except for the the off- Fig. Illustratingin .levatime impeller ditvmehanism 'whichis .not ilhistmtedin the foregoing figures:

THEM, an-enlarsed detail view in icentralxverfleiitsee'tton ottheaeration'impller;

Fig.5, a cross-sectiontaken on the llne:55 of Fig.4; and

Fig. '6, a cross-section taken through the-agitationimpelleron the line 6-5 of. Fig; 2 and drawn to a scale somewhat less enlarged than Figs. v5 and 6.

Referring -.to the drawings: th :machine zillus .trated comprises abank of flotation cells-.l.ll,-ithe vtailingsv from one .cell. passing into .thenext succeeding cellover a weir H in customary manner.

.Each cell'is equipped with an inlet 12 disposed at the lower "partof an intake column 13- defined .at the .front'of the cell. In the instance 'ofthe first cell of theseries'the intake column-is defined by suitablyprovided walls, as shown. :In tsucceeding cells .thevintake columnis defined in-part by the Weir l l.

The individual cell l0 comprises a container-for the flotation pulp :fiowin into :the "cell throu h inlet l2, such container being made upof ,a -base portion I4, which partially definesa'pulp :fiow conduit 'or aeration chamber I5, and ofa superimposedportion l6, whichparti'ally defines pulp recirculation (columns l1;at Opposite sides .ofthe .cell.

.Advantageously, the; pulp columns .H .flare out- .wardly as they rise tothe level-of froth-discharge lips 18, and, at their bottoms, have controlled communication with the aeration chamber I5 through longitudinallyeextending recirculation passages IS. The degree ofopeningrof suchgpasrsages is controlled by butterfly dampers 20, which are arranged. for adjustment manually'hymeans ofirespective handles 2 1;:Fig. -1.

"The aeration chamber 15 andoppositelyydisposed .pulp columns I I are further defined by the outer walls of an innercontainer 22, which ;.pro' vides an agitation chamber 23 aforaeratedfflotae tion; pulp.

- tThe bottomzof this seco-ndor inner :container -22'ls formed "by a cheek :plate:tray;24,..:supported by inturnedafianges Mayand hasacentrallysdis posed opening into whichifitsa dependingtportion of the agitation impeller described hereinafter. .The top of container 22 is-1open,tand:is disposed Well below the. level of "frothdischarge .'.lips 18 11:0 provide .for adequate froth "migration :from the bubble column "established within :eontainern fl, across :pulpcolumns I Land overfrothedischarge .lips 18 intofroth launders 225 which extend-longitu'dinany of the bank of cells 1 lo alonglopposite sides thereof.

"The intake column [3 advantageously comprehends the width of agitationchamber 23,lan-end :wall 22b otthe .inner container.flseparating'the "Likewise, -a stilling wen'ze; defined a: the

subject of my copending application for patent, Serial No. 89,632, filed Apr. 26, 1949, wherein are disclosed concepts generic to the subject matter .of the present application, aeration is accom- 'plished' within the pulp flow conduit or aeration chamber by means of an aerating impeller, and the aerated pulp is drawn into and agitated within the agitation chamber by means of an agitating impeller.

For this purpose, a tubular drive shaft 36 [extends downwardly through agitation chamber 23 and through the center of the aforementioned centrally-disposed opening in cheek plate tray 24 to a termination spaced upwardly from the bottom of the aeration chamber l5.

Fixed to the drive shaft 36 so its depending annular lip 3|a is snugly rotatable within the aforesaid opening in cheek plate tray'24, is a hollow disk type agitation impeller 3| having discharge passages 32, Fig. 6, radiating from the intake opening 33 defined by annular lip'3la. Swirl grids 34 rising from an annular swirl grid plate 35 are advantageously provided to stabilize the agitating action of impeller 3|.

Fixed to the end of drive shaft 36 below im- 3 peller 3| and within aeration chamber I5 is disk-type aeration impeller 36.

Such impeller 36 is preferably of a novel construction, affording superior dissemination of air in the pulp contained by aeration chamber I5. As illustrated, Figs. 4 and 5, the impeller 36 has a receiving recess 31 centrally located in its upper surface, into which is tightly fitted the lower end of the tubular drive shaft 30. The recess 31 is preferably countersunk to provide a chamber 38 from which lead a plurality of radial-air ejector passages 39, desirably of tubular formation as shown. The circumferential periphery 'of impeller 36 is symmetrically notchedto-provide ports of entry 46 for the air as it discharges from the respective ejector passages 24, it being understood that such passages open into the respective ports of entry. For obtaining an especially effective mixture of air with the pulp, such ports of entry 40 are formed with a radial leading portion 400,. and a concavely arcuate trailing portion 46b, all as set forth in my aforementioned patent application S. N. 89,632. we

For mixing the reagents with the flotation pulp, a tube 4| of smaller diameter than the tubular' drive'shaft 36 is inserted longitudinally and concentrically Within such shaft so as to terminate within aeration impeller 36 preferably just above chamber 38 thereof, as illustrated.

The drive shaft 30'is mounted for rotation within an elongate bearing assembly 42, making up part of a supporting superstructure 43 which rests upon the upper portion I5 of the cell, as by means of cross-beams 44, Rotation of shafts 30 may be effected by any suitable means, for example by an electric motor (not shown) belted to a drive pulley 45 which is rigidly fixed to'the shaft.

The air is delivered to chamber 38 of aeration impeller 36 through the annular longitudinal 4 passage 46 defined between reagent delivery tube 4| and the interior walls of drive shaft 30. For introducing air into passage 46, a pipe-fitting 41 is mounted at the upper end of drive shaft 30 by means of a conventional rotary joint assembly 43. A pipe 49 supplies air to pipe-fitting 41, and thus to passage 46 of the tubular drive shaft 30, from any suitable's'ou'rce; "Preferably the source is a pressure source, such'as an air compressor, so there will be a forcible introduction of air into the centrifugal aeration impeller 36.

In operation, flotation pulp is continuously introduced into the cell It) through the intake column l3 and inlet |2 thereof, to form a body of pulp within both the aeration chamber l5 and the agitation chamber 23, as well as the respective pulp columns l1 and stilling well 26. Outflow occurs over the weir Rotation of the tubular drive shaft 30, together with supply of air and reagents through the passages above-described, effects a substantially uniform aeration of the pulp in chamber l5, as Well as thorough intermixture of the reagents therewith. Furthermore, such rotation of drive shaft 30 produces a simultaneous and corresponding rotation of agitation impeller 3|, which, in' effect, sucks aerated pulp from chamber l5 and forcibly discharges it into the body of pulp within agitation chamber 22, thereby not only agitating such pulp so that bubbles carrying valuable particles picked up from the pulp may easily rise to the surface and form a thicklayer of froth 56, but also acting upon such aerated pulp to break up'large bubbles into small bubbles which make up a copious, heavily-laden froth concentrate. The swirl grids 34 actjto stabilize the agitated pulp and to cause a substantially vertical circulation thereof, so themineral-laden bubbles will rise to .the surface in substantially direct lines.

Recirculation of aerated and agitated pulp through the aeration and agitation chambers may be effected in controlled amount through the respective pulp columns ll by means ofv suitable settingsof .the damper valves 20. i

Spentpulp from a low point in the bubbl column of container 22 flows out of the cell l0 through the .tailings-diseharge opening 2| for similar treatment in a subsequent cell -of the series, or for discard in the case of the final cell, theoutfiow passing through the stilling well 26 and over weir H, in conventional manner; A sand gate .5I' permits controlled outflow from aeration chamber 15 directly into the lower part of the intake column l3 ofthe succeeding cell of ;the series. l 1

It should'be'noted that the location of the agitation: impellery 3| within and immediately above theapassageproviding flow communication from the aeration chamber to the agitation chamber, and the disposition of the aeration impeller 36 therebelow, provide an especially efficient action for the machine as a whole.

Whereas this invention is here illustrated and described with respect to a presently preferred specific construction thereof, it should be understood that various changes may be made therein and various'other constructions may be resorted to on the basis ofthe teachings hereof, by those skilledin the art, without departing from the protective scope of the following claims.

1. A flotation. machine, comprising an open container forlpulp; pulp, inflowg n eans, communicating with one end of said container adjacent the bottom thereof; tailings outflow means leading from said container at the other end thereof; a second and smaller open container for pulp disposed within the first container and spaced upwardly from the bottom and inwardly of side walls thereof to define a pulp fiow conduit below the bottom of said second container, in flow communication with said pulp inflow means, and to define, further, pulp recirculation columns between side walls of said first and second containers, in flow communication with the open top of said second container and with said pulp flow conduit; pulp aerating means operably disposed within said pulp fiow conduit; passage means leading through the said bottom of the second container; an agitation impeller operatively disposed within said second container above said passage means and adjacent the said bottom thereof, so as to be completely submerged and surrounded by liquid, without access to the atmosphere, during operation of the machine, for aiding elevation of pulp through said passage means and for agitating said pulp within the said second container; and froth overfiow lips defined along the upper margins of side walls of said first container, said second container being of effectively less height than said first container to provide for recirculation flow of pulp over side walls thereof below said froth overflow lips and underlying the overflowing froth column.

2. The combination recited in claim 1, wherein the aerating means comprises an aeration impeller and communicating source of air disposed within the pulp flow conduit directly below the agitation impeller.

3. The combination recited in claim 2, wherein both impellers are fixed to a tubular drive shaft extending vertically within both chambers, and wherein air is supplied to the aeration impeller through said drive shaft.

4. A flotation machine, as defined in claim 1, wherein there are provided, in the pulp circulation columns, valve means for controlling flow of pulp.

5. A flotation machine as defined in claim 1, wherein the agitation impeller has a depending, annular lip portion extending through the passage means in the bottom of the second container, in substantially contiguous relationship with the defining walls of said passage means.

6. The combination recited in claim 5, wherein the drive shaft is hollow for the delivery of air to the aeration impeller, and the aeration impeller comprises a disk having a retrocedent rim providing a plurality of enlarged ports of entry inwardly of the circumferential periphery of the disk for the air as it is discharged into the pulp, and a plurality of air-ejecting, tubular passages extending from intake communication with the hollow interior of the drive shaft to outlet communication with the respective ports of entry.

7. A flotation machine, comprising a container for flotation pulp, a substantially horizontal wall intermediate the depth of said container dividing said container into a lower pulp compartment, serving as an aeration chamber, and into an upper pulp compartment; a pair of mutually spaced, substantially vertical walls rising within said upper pulp compartment from said horizontal wall to a level below the froth-outflow level of said container and defining therebetween an agitation chamber immediately above said aeration chamber, said vertical walls being spaced from side walls of said container to define pulp-recirculation passages at opposite sides of said agitation chamber and in communication with said aeration chamber; froth discharge means disposed above said passages; an opening in said horizontal wall establishing communication between said aeration chamber and said agitation chamber; an agitation impeller rotatable within said opening; and means for aerating pulp within said aeration chamber.

ROGER DERING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 954,951 Furowicz Apr. 12, 1910 1,285,061 Daman Nov. 19, 1918 1,374,445 Greenawalt Apr. 12, 1921 1,583,141 Greenawalt May 4, 1926 1,925,777 Sperling Sept. 5, 1933 2,141,862 Hall Dec. 27, 1938 2,189,779 Damon Feb. 13, 1940 2,232,388 Ingalls Feb. 18, 1941 2,433,592 Booth Dec. 30, 1947 FOREIGN PATENTS Number Country Date 381,776 Great Britain Oct. 13, 1932 388,185 Great Britain Feb. 23, 1933

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