US2166392A - Ore concentration - Google Patents

Description

July 18, 1939. H. H. BURTON ORE CONCENTRATION Filed sept. 1o, 193s Patented July 18, 1939 UNITED STATES PATENT OFFICE Burton-Allen Gold Reclaiming Corporation,

Wilmington, Del., a corporation of Delaware Application September l0, 1936, Serial No. `100,140

2 Claims.

The present invention relates to an improved means and method for concentrating the val ues contained in ores, sands, and like materials-the object'being to subject such materials, in the form of `free-owing pulps, to repeated progressive removals therefrom ofthe gangue or lighter Worthless matter-thereby to obtain, eiTiciently and economically as the process continues, a richer and richer concentrate oi.' the heavier values-or metalliierous substances.

My invention `provides a compact apparatus into and through which the metal-bearing material in Wet pulp 'form lovvsat a regulable rate, and from `vvhich there are a plurality of slime discharges carrying off the gangue or Waste at nearly the `same rate-the small difference being represented, `for all practical purposes, by a singleconstant delivery of a concentrated pulp residue which is exceedingly rich in values.

My invention `is applicable to the treatment o1' practically all-varieties and grades of crushed or divided ores and metal-bearing sands, or similar materials containing values, which are sus* ceptible of forming `With water, or other liquid,

a free-flowing `pulp-it being immaterial What previous 'treatment such materials have been subjected to, or Whether'or not any free gold, silver, or other values contained therein have previously been removed. Itis Well known Athat in many ores, metalbearing sands and like materials, no `matter how finely crushed or divided, the values do not exist in a free or relatively pure state, but instead are combined more or less intimately with other substances; for ex ample, much fof the gold in such `crushed ores, sands and like materials is so combined or coated with sulphides thatit cannot possibly be isolated from the lighter particles or gangue, either by the mercury amalgamation process, or by the cyanide processin both of which there is inevitably a heavy vloss of such values. My invention lends itself to the concentration and recovery, economically and eiciently, of all such values as are difficult, if not impossible, to recover by the various methods of concentration heretofore practiced.

By my invention, as hereinafterdescribed, the separation and discard of the Worthless and lighter substances inthe pulp is effected continuously and progressively during the passage of the pulp through my improved apparatus, Wherein said pulp, as fast as received, is subjected to an initial expulsion therefrom of slimes that contain .and car-ry oi a considerable portion of the gangue or lighter worthless ingredientsthus progressively creating at a much-reduced volumetric rate an intermediate product in the form of a pulp residue Which is relatively rich in the heavier values\or metalliferous ingredients. On `such residue, as fast as formed, is repeated the above-described slime-expelling operation--this, of course, lstill further materially decreasing the volume of and increasing the value-concentration in the pulp residue that, as a second intermediate product, is progressively obtained by the above described action. In this Way, by repeating for as many times as is necessary the slime-expelling operation, each time on a smaller-volume more concentrated pulp residuejthere is lobtained at the end of the process a single constant small discharge of an exceedingly rich concentrate of all the heavier values or metalliferous substances contained in said pulp. Other and further objects and advantages of the invention Will be made apparent in the following detailed ydescription thereof, reference being had in this connection to the accompanying-drawing, wherein the single gure is a sectional view-,illustrating the principles of my invention, and showing one form and ar- 25 rangement of apparatus for carrying it into effect.

AReferring `to vsaid drawing, `I have shown a plurality of concentrating traps arranged in series, and it will be obvious that any desired number of such traps similarly arranged may be employed, depending upon the character of the pulp and the degree of concentration required. Said trapsfexcept for si-ze, are substantially identical in construction, each comprising in theillustrative form shown, a base portion l, upon which is suitably mounted a shell 2, the latter providing a chamber 3 into Which the pulp is fed by a suitable duct or tube 4, the `latter passing through `the inclosed top 5 of chamber 3 and having Aits outletnear the bottom of said chamber. Said bottom is constituted by a rack or plate 6 having relatively large openings over its `entire area, these openings permitting the free passage therethrough of any and all of the particles or solid `matter carried in suspension by the pulp; however, the openings in plate or rack 6 do not permit the passage therethrough of any of the relatively large rags 1, 'l which, as shown in the drawing, occupy much of the space in chamber 3-the rack or plate 5 serving as a support for this mass of rags. The latter are preferably of clay in substantially spherical form, and they preferably surround the entrance tube 4 to about the level of a lateral opening 8 in the upper part of shell 2, and at or near such level is provided a substantially horizontal shelf 9, for a purpose to be hereinafter described.

Below the opening 8, the shell 2 has another opening I 0, which establishes communication between the rag-filled main chamber 3 and a supplementary rag-filled chamber II. The top of chamber II is provided by the aforesaid shelf 9, the latter extending outwardly into relatively close proximity to a baille plate I2, here shown as supported by walls I3, I3 that constitute the sides of chamber II. The bottom I4 of chamber II preferably slopes sharply upwardly from the opening I0, and along the upper edge of said bottom is provided a dam or obstruction I 5 which is appreciably above the level of the lower edge of baille plate I2 and is spaced substantially outward from said baille plate I2, thus to leave the chamber II open between plate I2 and dam I5 for the Voutward flow, over said dam, of the gangue or waste matter in the pulp, as hereinafter described.

The base I supports another shell I6 which provides, below the plate or rack 6, another chamber II, the bottom of said chamber being constituted by a removable screen I8. Any suitable means are provided to permit removal of a screen I8 and the substitution in its place of a similar screen of different mesh; as here shown, the screen is removably clamped between flanges I9'and 20 provided, respectively, by the shell I6 and by another shell 2I below the screen, said last-named shell inclosing a chamber 22 to which the pulp has access by way of the apertures in screen I8, Preferably, for a fine-ground pulp, a screen I8 of fine mesh is employed, while if the pulp is coarse-ground, a screen of larger mesh is used; in any case, the mesh of such screen must be large enough for the solid particles of the pulp to pass through it, but in no case must the mesh allow the passage through the screen of the rags 23, 23 supported thereon Within the chamber II-these rags, as shown. being preferably smaller in size than the rags 1 which are contained in the chambers 3 and II.

Within the chamber II, between the rags 23 and the plate 6, is arranged a preferably annular nozzle pipe 24, having a plurality of jet openings for the impingement, as hereinafter described, of streams or jets of water and steam into the pulp and against the mass of rags 1 above and against the layers of rags 23 below. Within the chamber 22 is a baille or guard 25, arranged over the open mouth of a nozzle pipe 26, to prevent direct impingement of the water and steam discharge from said nozzle against the screen I8. The outlet from chamber 22 is indicated at 21, and is provided with a suitable valve 28, the position of which is adjusted by the setting of an operating handle 29, so as to govern the rate of discharge of the concentrate from chamber 22 into an open offtake passage 30, the latter being preferably equipped with a suitable baille 38'. In said offtake passage 30, the concentrated pulp flows by gravity through an opening 3l into a pumping chamber 32-the opening 3| being controlled by a suitable check valve 33, preferably of the flapper type, which is adapted to permit the passage of the concentrate through the opening 3| in one direction only, viz'from the oiftake into the chamber; the valve 33 automatically closes whenever the pressure in the chamber 32 tends to cause any flow of the concentrate through opening 3I in the reverse direction. 'Ihe pumping action in each chamber 32 is preferably effected by the admission to said chamber of steam, air, or other gas, under pressure, as by means of a pipe 34 which lets into each chamber 32 near the top thereof-the two pipes 34 branching, as herein shown, from a pressure fluid supply pipe 35 in which is preferably arranged a mechanically operated valve 36. The valve 3G is adapted, in the operation of the system, to be alternately opened and closed, at a regulable rate to produce a more or less rapid pulsation in the admission of fluid pressure to the chambers 32- this pressure in each chamber being communicated to the liquid-carried concentrate in the lower part of the chamber, to force said material upwardly through a pipe 31 which communicates with the entrance tube 4 of the next succeeding trap of the series.

The main 38 which furnishes pressure fluid for pump supply pipe 35 may also furnish pressure iluid to another supply pipe 39 having therein a suitable mechanically operated valve 4i! which, like the valve 36, is alternately opened and closed in order to give the steam or other gas, along with the water or other liquid which is admitted to each trap, a pulsating action that agitates the rags 1 and 23 and contributes very materially to the separation of the gangue from the values, as hereinafter described. Beyond the valve 40, the pressure supply pipe 39 has a branch 4I, equipped with a hand throttle valve 42; from this branch 4I, the steam, air, or other gas, under pressure is supplied by a connection 43 to the entrance duct 4 of each trap, the impulses through each connection 43 being in a downward direction into the pulp as it enters each trap, and said impulses serving to counteract and cushion any tendency of the entering pulp to be blown back through duct 4 by the upwardly directed fluid jets from the associated nozzle 24.

Provision is made for obtaining pulsating discharges of fluid, preferably water and steam, into each trap, not only through the annular nozzle 24 and the nozzle pipe 26, but also through.

a plurality of jet openings 44 provided in the bottom I4 of chamber II, these jet openings being supplied from a chamber 45. As shown in the drawing for illustrative purposes, these pulsating fluid discharges into each trap may be obtained by a branch connection 45 connecting the steam supply pipe 39 with a main 41 through which water or other liquid circulates in the direction of the arrows; from main 41, there is a branch connection 48 to each trap, the latter providing a valved feeder 49 to the chamber 45 and a valved extension 50 that feeds both the nozzle pipe 2E and the annular nozzle 24. The steam pulsations of supply pipe 39 are thus impressed on the liquid that is discharged into each trap by the nozzle pipe 26 and jet openings 24 and 44, the steam from branch 4B being to a certain extent mixed and mingled with the liquid discharged through these openings; this pulsating effect is preferably made even more pronounced and the mixture of liquid and gas made even more intimate by another steam branch 5I from supply 39, said branch having a connection 52 to each trap that joins the feeder 50 in the vicinity of the latters connection to the annular nozzle 24. The operation of the apparatus as thus far described is substantially as follows:

The supply of pulp which flows by way of a suitable conduit 53 to the entrance tube 4 of the 75 fio rst trap is forced downward in said tube by the pulsating discharges of steam'from pipe 43, and is met at Ythe lower vend of tube 4 with a regulated upward pulsating discharge of liquid and steam from annular nozzle 24, these jets impinging on the coarse rags 1, 'l that substantially ill the chamber 3. At each pulsation, the rags 'l shift slightly upward and then settle downward by gravity, this agitation of the rags being accompanied by the gradual working-up through said rags of the lighter particles carried in suspension by the pulp, which lighter particles are naturally more susceptible to the lifting action vof the upwardly directed jets from nozzle 24 than are the heavier particles or Values contained `in said `pulp-although in this initial separation of the lights from the heavies, the ascending lights will be accompanied by some of the heavies, particularly the somewhat rnore finely ground heavies. Also the descending heavies will be accompanied by some of the lights, the descending particles in pulp form sifting down through the bottom layer of rags 1, 1 on the rack B and passing `through the perforations of said rack into the separating chamber l1 which, it will be understood, lls up with a liquid pulp in which, due to the initial separating action above described, the portion of heavies is greater than in the entering pulp, because of the considerable proportion of lights driven upwardly into the rags 1, 1 of chamber 3.

These particles, both lights and "heavies, that ascend in pulp form in chamber 3 will gradually ilow out of said chamber through opening 8 onto shelf 9, and will accumulate on said shelf in the form `of a progressively rising dam, as indicated at 54, which acts to retard any tendency of this thin pulp or slime to flow too rapidly out through the opening 8. Said pulp, discharging over the dam 54, and containing lights and the ner heavies in suspension, ows by gravity into supplementary separating chamber I l, the latter, as aforesaid, containing rags 1, 1 which are agitated by the pulsating jets of fluid, preferably water and steam, discharged through the openings 44. Consequently, in chamber Il occurs a separation of lights from heavies similar to that occurring in chamber 3--the heavies working down through the rags of chamber Il to reenter the chamN ber 3 through opening l0, while the lights, by the elevating action of the jets of water and steam from openings 44, are caused to work up through the rags in chamber Il toward the open portion of said chamber beyond the baille l2, whence they are discharged continuously in a thin pulp or slime over the dam l5 and into a suitable offtake trough 55 for the disposal of this waste material. Thus, in chamber Il occurs an almost complete recovery of values which would otherwise be carried off and discarded with the gangue or Worthless portion of the pulpthese values being returned, as above described, through opening lll for the enrichment of the somewhat rei-ined or concentrated pulp that, as above described, is constantly passing down through rack 6 into chamber I1.

In the chambers l1 and 22, separated by screen i8, the pulp undergoes a further concentration, by the pulsating steam and water discharges of nozzle pipe 26 and the downwardly directed jet openings of ,annular nozzle 2lithese combined discharges producing an agitation or intermittent working up and down of the ner rags 23 on screen I8, that allows the heavies to sift. down through said screen while freeing and forcing upwardly a considerable portion of the "lights until some oi the latter at least come under the influence of the upwardly directed jets of annular nozzle 24, and are thus forced back into the mass of rags 1 of chamber 3, for ultimate discharge with the worthless slime that passes out over the dam l5. Thus the pulp that reaches the bottom of chamber 22 is considerably richer and more concentrated in heavies than the pulp which enters the rst trap.

The concentrated pulp has its outflow from chamber 22 by way of passage 21, and it will be obvious that the position of adjustment of the valve 28 in passage 21 governs not only the rate of ilow of the concentrated pulp into oiltake 3i), but also, indirectly, the rate of discharge of the slimes vwhich carry ofi the gangue" into trough 55. In other words, the valve 28 is so adjusted by the operator as to maintain the proper balance between the rate of inflow of the entering pulp, andthe rate of outflow of the concentrated pulp, for an efficient and economical partial separation of the lights from the heavies in any given pulp; these conditions vary widely with different kinds and grades of pulp and with different varieties of ores and metal-bearing sands, and provision is accordingly made for inspection and testing of the pulp at appropriate points, to determine its degree of concentration, and in accordance with such determination to change, if necessary, the setting of the valve `28, and to increase or decrease, as required, the amount of steam and water admitted to the trap, by suitable opening or closing movements of the valves that are provided in the Vfeed lines 49 and 50. To permit of such inspection and testing of the concentrate, each pump chamber 32 near its bottom may be equipped with a draw-off cock 56; in addition,

each pipe or -duct 31 through Which the concentrated pulp is forced, 'by pressure in. said pump chamber to the Vnext trap of the series, may provide, as shown, a fitting or enlargement 51 which is open, not only to permit inspection of the passing material, but also to maintain said material substantially at atmospheric pressure, as it flows into the next trap.

The Ipulp material allowed to discharge into oftake 3@ of the rst trap ows through opening 3i into pump chamber 32; this pulp, which contains considerably less of the gangue than the original entering pulp, may require the'addition some water to restore the iree-ilowing characterof the pulp, in its passage thro-ugh pipe 31 to the next trap of the series; if additional water is needed, the same may be readily supn plied by admitting it directly to `the offtake 30 which is open to the atmosphere. The next trap of the series, as shown, is in all respects the duplicate in construction of the first trap, but is preferably made considerably smaller in size, as it is not required to handle in a given time as great a Volume of the richer pulp as the volume of original Apulp introduced in the same time to the first trap. In other words, assuming the originally entering pulp and the enriched pulp to be of substantially the same consistency (the same proportion of `solids to liquids), it is clear that the Very considerable quantity of lights e that pass-01T, as above described, with the slimes from the top of the first trap secures an appreciable reduction in 4the volume of material that lpases to the second trap-and so on for subsequent traps of the series which in number may (vll be as many or as few as required. The progressive separating action above described by which the lights are all the time being thrown 01T, causing the pulp to become relatively richer and richer in heavies, takes place in each of the succeeding tra-ps of the series in exactly the same manner as above described for the rst trap. Finally, in the smallest or last trap of the series (here shown as the third trap for convenience of illustration), the concentrate attains such a preponderance of heavies as to make further concentration impracticable; in this last trap, the construction may be slightly different in providing below the screen I8 a second screen 58, the latter being held between a casing member 2| and an additional casing member 59, inclosing a chamber 60. The material which works down through the layer of rags 6i on screen 58 is an enriched pulp in which the solid matter is practically all heavies, the last of the gangue or Worthless lights having been discharged into the trough 55 of the final trap. This concentrated pulp is allowed to accumulate in chamber 60 or may be drawn off as a substantially constant discharge through outlet 62, and screened to separate the solids from the liquidthe solids being almost Wholly composed of the heavier mineral particles or "va1ues in a form suitable for reduction by smelting or otherwise.

There is never any need, in the operation of my improved process and apparatus, to shut down or to discontinue temporarily the feeding in of the material in order to permit accumulated values to be collected. As distinguished fromY most ordinary concentrating operations, where considerable percentages of the values or heavies do not participate in the flow of the mass of pulp through the apparatus, but are left behind for collection on subsequent periodic shut-downs in the delivery of the material, in my concentrating operation, the values are carried along progressively through the entire apparatus, the latter functioning to obtain in a series of stages a progressive transformation both quantitatively and qualitatively of the` Stream of pulp that flows therethrough. Said pulp stream, by virtue of the slimes discarded therefrom in the iirst trap of the series, is rendered materially smaller in volume and relatively richer in values; thereupon by the subjection of this intermediate product as fast as formed to the second trap of the series, is obtained a stream of pulp residue still smaller 1n Volume and more concentrated in values. And so on. as successive traps are encountered by these gradually diminishing and increasingly concentrated streams of the pulp which, in each case, carry along practically all of the originallypresent heavier ingredients or values-until finally, from the last and smallest trap of the series is obtained a pulp delivery at a volumetric rate which is only a very small fraction of the volumetric rate of feed of the original pulp; however, in this final discharge from chamber 60 of the last trap, the heavies or "va1ues are so predominant as to make further concentration unnecessary. Such small discharge from the bottom of the last trap is the sole product of my process; such discharge retains practically all of the values and is free of practically all of the gangue that entered with the original pulp. In the operation of my process, this flnal end product discharging from the bottom of the last trap is always being continuously and progressively produced, so that the process in its entirety is truly continuous throughout-there being no need for any interruptions 1n the delivery of the original pulp stream to the system, nor for any interruptions in the passage of the gradually-diminishing pulp stream therethrough.

Although the pulp liquid may be used over and over again in the system, there 1s no tendency of the same to sour or to become polluted, since there is a continuous addition thereto of live steam which has a beneficial purifying action in destroying any fungus or bacteria that enters with the ore, sand, or other material being treated. This continuous introduction of steam to the pulp stream substantially replenishes all water or pulp liquid that is lost by the periodic removal of the sediments from the slimes that flow off through the troughs 55, 55 by the discharge of the iinal pulp concentrate from chamber BU-this enabling the apparatus to be operated economically even in regions where water is scarce and expensive.

I claim:

l, In ore concentrating apparatus of the class described, for the separation of lights from heavies in a free-iiowing pulp, a pulp-receiving chamber having a screen at its bottom, a mass of rags in said chamber supported on said screen, the latters perforations permitting passage therethrough of all the solid matter of said pulp, means for producing intermittent upward surges of fluid through said chamber, to agitate the rags" therein and to discharge upwardly through said rags some of the lighter particles of the pulp, a second chamber communicating with the top of said rst chamber and receiving therefrom said upwardly discharged material, a mass of rags in said second chamber, means for producing in said second chamber intermittent surges of fluid for the alternate elevations and settlings of the "rags therein, thereby to float off the lighter pulp particles in said second chamber and to cause settling through said rags of the heavier pulp particles, and a substantially horizontal shelf in the path of pulp flow from the rst chamber to the second chamber, said shelf providing ior the support, in dam formation, of lighter pulp particles deposited by said pulp iiow.

2. In ore concentrating apparatus of the class described, for the separation of lights from heavies in a free-iiowing pulp, a pulp-receiving chamber containing a mass of rags, the bottom of said chamber having perforations therein of such size as to permit passage therethrough of all the solid ingredients of said pulp, but to prevent passage therethrough of any oi said rags, means for producing intermittent upward surges of iiuid against said rags co-incident with the downward gravitational passage therethrough of the pulp, thereby through alternate elevations and settlings of said rags to oat off the lighter pulp particles and to cause descent through said rags of heavier pulp particles, an outlet from the upper part of said chamber above said rag mass, for said lighter oated-oi particles, and a substantially horizontal shelf, associated with said outlet, and whereon said floated-off lighter particles nd support to form a dam.

HARRY H. BURTON.

Images