US2028179A - Flotation machine - Google Patents

Description

Jan. 2 1, 1936.

` R. P. AKINS FLoTATIoN MACHINE Filed NOV. '7, 1955 2 Sheets-Sheet, 2

Patented Jan. 21, 1936 PATENT OFFICE;

FLOTATION MACHINE Randall P. Akins, Denver, Colo.

Application November 7 Claims.

This invention relates to a otation machine for the concentration of ores and has for its principal object the provision of a machine of this character in which the risingcolumn of air will efficiently act as the agitating medium forthe pulp and provide a circulating current which will effectively bring the air into intimate contact with all of the ore particles. f

Another object is to so construct the tank that the rising column of bubbles will be continuously forced toward the froth overflow to rapidly and continuously clear the froth from the machine.

A further object is to provide an air dispersion medium of a type which will prevent water from entering the air boxes, either while operating or during shut downs, and which will be so constructed as to assist in the propulsion of the gangue toward the discharge of the machine.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and eiciency. These will become more apparent from the following description.

In the following detailed description of the invention reference is had to the accompanying drawings which forms a part hereof. Like numerals referto like parts in all views of the drawings and throughout the description.

In the drawings:

Fig. 1 isa cross section through the improved flotation machine, taken onthe line I-I, Fig. 5.

Fig. 2 is a detail face view of the upper baille board.

'Fig 3 is a detail face view of the moveable baffle board.

Fig. 4 is a face view of the impeller.

Fig. 5 is a longitudinal section, taken on the line 5-5, Fig. 1.

Fig. 6 is a detail plan view of the air dispersion plate.

Fig. 7 is a cross section through the dispersion plate taken on the line 1-1, Fig. 5.

The invention comprises a relatively long spitz-kasten or tank I0. The bottom of the tank is formed with a. long, relatively narrow, rectangular section, or channel as shown at Above the channel I I, the front wall I2 of the tank flares outwardly at an angle of approximately 45 terminating in a froth overflow lip I3, in front of which the usual froth launder I4 is positioned. The back wall of the tank also flares outwardly, preferably at a steeper angle as shown at |5,`-"thence extends upwardly as shown et I6; and thence inwardly as shown at to a 7, 1933, Serial No. 696,929

horizontal top board or hood I8, `which extends over and above the channel |I.

'I'he upper area of the tank I0 is divided laterally into a series of cells by means of lateral partitions I9 which terminate a considerable distance above the channel Below each of the lateral partitions ISis an air partition 20 which divides the channel into a series of air chambers 2|. The top of each air chamber 2| is covered by means of a perforated plate 22.

It is desiredV to call special attention to the fact that the plates 22 are arranged in successive steps, that is, each plate is lower than the preceding plate, as the discharge extremity of the tank ID is approached. A feed box 23 is positioned at the head end of the tank and opens thereto through a feed opening 24. A tailings discharge pipe 25 opens from the rear end of the tank at a lower level than the lowermost plate 22. Air is fed to the air chambers 2| from an air header 26 which communicates with each air chamber through an independent air pipe 2'I, each of which is controlled by a valve 28. A froth board 4| is spaced from the end wall of the tank Ill immediately above the last air partition 29. The latter is also spaced from the end wall to form a settling chamber 4l for the tailings outlet. Drain nipples 48 extend through the bottom of each air chamber 2|, and are closed by means of suitable plugs 49.

In each cell an upper baffle board'29 is placed. The upper bale boards extend downwardly from the hood I8 substantially to or slightly below the pulp level. The baffle boards 29 are perforated as shown in Fig. 2, preferably with a series of Vround perforations 30, and a second series of elongated perforations 3|. Immediately below the baffle board 29 is a moveable `baille board 32 which rests at its Jextremities in socket members 33 positioned against the partitions I9. A third, inclined baiile board 34 is placed between the board 32 and the rear tank wall I6, the board being inclined toward the back at its top.

In use, the tailings discharge pipe 25 is turned upwardly at the extremity of the tank a suflicient distance to maintain the solution level therein at the desired point, preferably just below the froth lip I3, as indicated in Fig. 1. 'Air is supplied under the proper pressure to the air chambers 2| and issues through the dispersion plates 22 into the solution, arising therein in the form of bubbles. The pulp is fed into the feed box 23 and flows into the first cell and from there, into the succeeding cells below the partitions |9. The remaining pulp and gangue discharges into the tailings chamber 4|, thence into the tailings discharge pipe 25 where it rises and overows the top thereof.

The air arising through the screens 22 passes through the pulp, collecting the metallic values therefrom and elevating them in a rising column of bubbles. This rising column creates an upward current in the solution which strikes the inclined baille boards 32 and 34, and is directed by these boards rearwardly and upwardly against the forwardly inclined back |1. The forwardly inclined back |1 directs the froth forwardly conf stantly urged by the rising column of bubbles at the rear of the tank. This forwardly' moving froth passes through the perforations 30 and 3| in the baille board 29 and onward to the froth overflow I3. A froth scraper 35 may be provided at this point to assist in passing the froth over into the launder I4, although the machine has been found to operate very satisfactorily without a scraper.

Naturally a quantity of pulp, gangue and solution will be carn'edupwardly with the rising col umn of bubbles. This material will be deflected by the bale board 29 so that it will descend along the forward. face of the baille 32, which will prevent it from interfering with. the rising column vof bubbles. The inclined front board I2 will return this descending material over the dispersion plates 22 from whence it will again be carried upwardly adjacent the rear wall of the tank. 'Ihus all particles of the pulp will be subjected to and travel with the rising column of air bubbles several times during their passage through each cell.

-Tliis whirling action imparts a spiral line of travel throughout the length of the tank I to all of the solid particles therein. As they reach the partition I9 of each cell they are carried beneath the partition and will rise in the next cell. The coarse, heavy, non-floatable material will be carried along each dispersion plate 22 by the spiral current and will fall to the next succeeding plate throughout the length of the machine.

It is desired to call particular attention to the movable baille 32. This baiie is provided with a series of perforations 42 along its upper edge so as to allow the surface current and bubbles to pass. It can be swung to any desired position so as to regulate the rate of circulation in the cell to a point of maximum recovery for the particular ore being treated.

It is desired to call particular attention to the dispersion medium or plate 22 which is shown in detail in Figs. 6 and 7. vThis consists of a relatively thin plate of non-corrosive material lthrough which a series of narrow, staggered, slots are pierced in such a way as to raise the material about each slot on the upper surface of the plate giving it a corrugated effect. This causes the slots to have a wider opening at the bottom than at the top which prevents them from packing ory lling with material. It has been found that a plate of this construction will automatically seal itself should the supply of air be v cut olf so that the pulp will not leak through and enter the air chambers 2|. This sealing effect is accomplished by the lines or slimes settling over the entire surface of the plate automatically.

The machine as thus far described will operate eiclently and satisfactorily with a high recovery of values on the usual feed. It might be desirable however in some installations to provide a mechanical impeller in the rst cell immediately in front of and below the feed opening 24 to act as an emulsier or conditioner or spumer for the entering pulp.

Such a device is illustrated in cell of Fig. 4 and preferably comprises a vertical shaft 36 suspended in vertical bearings .31 and terminating immediately above the dispersion plate 22. This shaft may be rotated from a suitable motor 38 through a belt drive 39. On the bottom of the shaft 36, is an upwardly forcing impeller 40. Spaced a short distance above the impeller 40 is a downwardly forcing impeller 4|. The incoming pulp from the opening 24 falls upon the impeller 4| and is forced downwardly against a rising column of solution and air from the impeller 40. These two impacting columns contact and are forced violently outward in a sheet from between the two impellers,. creating an eiective emulsication of the pulp which greatly increases the effectiveness of the action of the remaining cells.

The impellers 40 and 4| are preferably formed with an annular, conical, outer band 44 supported upon the extremities of a series of inclined vanes 43 as shown in detail in Fig. 4. The construction causes the solution to spread as it leaves the impeller and creates maximum agitation.

If desired a lever 50 (see Fig. 1) may be mounted over each cell and connected by means of a connecting rod. 5| with the moveable baffle 32. The lever may be held in any desired position by means of a suitable toothed sector 52. This allows ready and convenient adjustment of the angularity of the baffle 32.

It will be noted that the tailings discharge pipe 25 exits from the tank below the top of the lowermost perforated plate 22. This effectively prevents sand from building up on the bottom of the tank over the orificesin the perforated plates. It also allows the entire solution and pulp content to be drained from the tank and, as it drains, it will flow with 'cascading effect from one perforated plate to the next so as to wash the plates clean.

'I'he slotted openings 3| in the baille 29 allow wood chips and other debris to pass through the bafile and over the froth lip. The pulsating effect of the solution eventually aligns all chips with one or more of these slotted openings. It will be noted that the hooded top I8, in combination with the froth baille I9, forms an air chamber above the pulp. The rising air creates a compression in this chamber which causes the compressed air to blow through the perforations 30 and 3| and, in so doing, it blows the froth toward the discharge.

The lateral partitions I9 prevent intermingling of the rising mineral of one cell with the rising mineral in the adjacent cells and thereby allows the machine to be used to obtain a classifying effect by proper adjustment of the air valves 28. In use, it has been found that practically all of the lead in an ore may be floated in the first cell; the copper in the next cells; and the martensite iron in the last cells, dropping the sulphide iron to the tailings discharge, thus obtaining clean classification as well as a concentrate.

It is desired to call attention to the fact that it is not necessary to lift the h`eavy sand particles A feo been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent 1. A flotation machine comprising: a relatively long tank; a longitudinal air channel in the bottom of said tank; a series of air partitions dividing said air channel into a series of air chambers; a perforated member covering'each of said chambers; a forwardly inclined front wall in said tank above said channel terminating below the solution line in said tank; a rear w'all in said tank formed to extend in a general forward direction, said rear wall terminating above the solution line in said tank; and a baffle board positioned above said perforated medium and below the. solution level in said ttank, said baille board being inclined so as to direct rising material toward said rear wall, said baille board being hingedly supported so that its angular position may be varied at will.

2. A notation machine comprising: a relatively long tank; a longitudinal air channel in the bottom of said tank; a series of air partitions dividing said air channel into a series of air chambers; a perforated member covering each of said chambers; a forwardly inclined front wall in said tank above said channel terminating below the solution'line in said tank; a rear wall in said tank formed to extend in a general forward direction, said rear wall terminating above the solution line in said tank; and a bailie board positioned above said perforated medium and below the solution level in said tank, said baille board being 'inclined so as to direct rising material toward said rear wall, the upper edge of said baille board being perforated.

3. A notation machine comprising: a relatively long tank; a longitudinal air channel in the bottom of said tank; a series of air partitions dividing said air channel into a series of air chambers; a perforated member covering each of said chambers; a forwardly inclined front wall in said tank above said channel terminating below the solution line in said tank; a rear wall in said tank formed to extend in a general forward direction, said rear wall terminating above the solution line in said tank; a downwardly extending perforated bailie board extending from the forward extremity of said rear wall downwardly adjacent the solution -line in said tank; and a second baille board positioned below the solution level in said tank, said second baille board being movably mounted so that it may be brought' below said rst baille board when desired.

4. A notation machine comprising: a tank; an air chamber formed in the bottom of said tank; a perforated medium over said air chamber; means for supplying air to said air chamber;

a vertical shaft extending downwardly in said tank; and terminating above said perforated me?- dium; a first impeller positioned on the lower 5 extremity of said shaft and arranged to project solution upwardly from said perforated medium; a second impeller secured to said shaft above said first impeller and arranged yto project solution downwardly toward said first impeller; and means for'rotating said shaft.

5. A iiotationmachine comprising: a relatively long, narrow, box-like channel having an open top; a perforated plate closing the top of said channel; a front wall extending upwardly and forwardly from one side of said channel; a rear wall extending upwardly the other side of said channel, thence forwardly over said channel, so that both said front wall and said rear wall terminate above and on the same side of said channel, said lwalls enclosing a tank, said front wall terminating at the solution level and said rear Wall terminating above the solution level in said tank; a perforated froth baille extending downwardly from the forward extremity of said rear wall substantially to the solution level of said tank; and a baille board positioned below and extending downwardly from said first baille over and spaced from said inclined front wall.

6. A flotation machine comprising: a relatively-long, narrow, box-like channel having an open top; a perforated plate closing the top of said channel; a front wall extending upwardly and forwardly from one side of said channel; a rear wall extending upwardly the other side of said channel, thence forwardly over said channel, so that both said front wall and said rear wall terminate above and on the same side of said channel, said walls enclosing a tank, said front xover and spaced from said inclined front wall,

said baffle board being hingedly supported so that it may be inclined if desired.

7. A flotation machine comprising: a tank; an air channel in the bottom of said tank; a perforated plate covering said channel; a front wall in said tank extending forwardly and upwardly from the forward side of said channel and terminating in an overflow lip; a rear wall in said tank extending upwardly and forwardly from the rear side of said channel; and a baille board positioned above said plate and inclined to direct rising material toward said rear wall.

. RANDALL?. AmNs. 00

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