US1359496A - Concentration of ore - Google Patents

Description

F. G. GASCHE.

CONCENTRATION OF ORE.

APPLICATION FILED MAR. 5, 191a.

Patented Nov. 23, 1920.

2 $HEETSSHEET I.

F. G. GASCHE.

CONCENTRATION OF ORE.

APPLICATION FILED MAR. 5, 1918.

1 ,359,496, Patented Nov. 23, 1920.

. N v I A N r UNITED srarrs PATENT err-ice.

FERDINAND iGASCHE, OF CHICAGO, ILLINOIS.

CONQENTRATION. OF ORE.

esoaae.

Application filed March 5, 1918.

To all whom it may concern:

Be it known that I, FERDINAND G. GAscHE, a citizen of the United States, and. a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful. Improvements in and for the Concentration of Ores, of which the-following is a specification.

My invention relates to the treatment of ore to effect the separation of the metal particles and metal-bearing portions from the lighter gangue which comprises the greater bulk of the ore.

It is customary to ship ores direct from the mines to large concentrators, smelters, or cyanid extractors, where the values are recovered and either purchased or returned to the miner. The initial cost and the operating expenses of such plants, and the low efficiency thereof when operated on a small scale, practically preclude any other method of ore disposal. Furthermore, the present cost of concentrating ore and recovering the values therefrom, makes it unprofitable v to handle and ship any other than comparatively rich ores, with the result that lowgrade ore remains unmined or if mined is treated as waste and left upon the dump at the mine; and also, rich ore deposits remain unworked because too far distant from a smelter or extractor, or for lack of trans.

portation facilities.

The object of my invention is to overcome these difficulties by enabling men of little skill as metallurgists, and with little labor, to handle both high and low-grade ores and speedily, efiiciently and economically concentrate the valuable parts thereof, in the immediate vicinity of the mine or dump; and where with little added expense the concentrates may be refined, or because of the reduction in bulk may be profitably shipped even to distant points for that purpose.

My invention comprises a novel concentrating process and apparatus therefor, all as hereinafter described and particularly pointed'out in the claims:

The invention will be readily understood on reference to the accompanying drawings which form part of this specification and in which: Figure 1 is'a diagrammatic elevation of a concentrating plant embodying my invention;-Fig. 2 is a sectional detail of one of the air guns which 1 employ ;-Fig. 3 is a view of the nozzle on the parting line Specification of Letters Patent.

Patented Nov. 23, 1920.

Serial No. 220,427.

X-X of Fig. 2 viewed in the direction of the arrow A;-and, Fig. 4: is a like view in the direction of the arrow It should be understood at the outset that these drawings depict only the best apparatus which I have thus far devised, containing various novel features and combinations, but are not intended to imply that my invention is restricted thereto.

Fig. 1 illustrates a mill and power house, 2, near which is the concentrating floor, 3, covered by a long shed, 4:. The house, 2, contains a suitably driven conveyer, 5, for feeding ore to the mill or pulverizer, 6. The latter is driven by .an engine or motor, 7. The pulverized product leaves the mill through a swinging spout, 8, adapted to deliver the pulverized ore first to one and then to another of the tanks, 9. These tanks are closed at the top by means of hopper valves, 10. The bottom of each tank is in the form of a hopper and leading therefrom V is adown-spout, 11, which delivers into a mixing head, 12. This head, as hereinafter explained, contains devices for discharging the pulverized ore from the tanks into respective mixing chambers, 13. Each of these mixing chambers has an elbow, 14:, which communicates with the gun-or nozzle, 15, the details of which, in the preferred form, will be explained hereinafter. The house, 2, also contains an air compressing or blowing engine, preferably a turbine-blower, 16, of a two-stage type. The outlet pipe, 17, there of is connected to the'system at points within the tanks, 9, within the heads, 12, and preferably also within the nozzle, 15, as better explained hereinafter. It will be understood that the two heads, 12, and their elbows preferably join a single gun or nozzle, 15; that is, the plurality of tanks or reservoirs comprise means for continuously feeding the crushed ore to the gun 15.

The gun, 15, extends through the wall, a, of the shed, 4-, and preferably is positioned to discharge the ore horizontally across the concentrating floor, 8. Obviously the gun may be aimed up or down from the horizontal and thus is a change sometimes made for the purpose of compensating variations in the quality of the pulverized ore.

The floor, 3, may contain a simple flat surface, but preferably contains a plurality erably equipped with outlet conduits or tion comprehends the return of the poor or" low grade concentrate from the hopper, 19, to the mill to be reground and again discharged through the gun, 15. The shed has a closed far end, 4", which is preferably inclined, as shown. The roof of the shed,

or, if desired, the floor thereof, contains pressure relief openings, 21, and save for the necessary doors and windows, these may be the only openings in the walls of the shed.

Referring now to Figs. 2, 3, and 4, for the details of the preferred form of my novel gun or nozzle. the parts before referred to may be identified as follows, to-wit: The tank, 9, the down-spout, 11; the head, 12; the elbow, 14; the gun or nozzle, 15; and the blower pipe, 17. One branch, 17, of the pipe, 17, communicates with the pipes 22 and 23, containing respective valves 22 and 23. The pipe, 22, leads-through the side of the tank, 9. and is bent downwardly so that it substantially enters the down-spout, 11. At the lower end of the down-spout is a casting, 12', which contains in its central bore a tube, 24, having at its lower end a valve seat, 25, and also a conical surface, 26. A valve, 27, coacts with the seat, 25, to regulate the flow of ore from the tank. This valve is carried by a stem, 28, having a hand wheel, 29, on the exterior of the elbow portion, 13, 14. The upper part of the part 13 contains an enlarged cavity, 30, which is continued in the cavity, 31. of the intermediate casting or member, 12", of the head, This intermediate part contains an adjustable conical ring, 32, which is movable toward and from the cone, 26. to provide the conical air passage, '33; WVithin the part, 12, is an annular cavity. 34, which communicates with the pipe, 23, andhence with the conical passage, 33. A combining tube, 35, presents its large end to the lower end of the elbow, 14. The small end of the combining tube,- 35, delivers into the pipe. 36, one section, 36, of which preferably is flexible. To the forward end of the pipe, 36, I connect a second combining tube, 3.7 the tip of which is formed by a nozzle, 38. Attached to the part, 37, is a head, 39, which contains a central cavity, 40, and also an annular cavity, 41. The second branch, 17", of the blower pi e, 17, communicates with the cavity, 41. face plate, 42, closes the end of the head. 39, leaving, however, a narrow annular crack or opening, 43, whereby asagna communication is established between the cavity, 41, and the cavity, 40. A threaded opening, 43, contains a nozzle plug, 44,

which has a specially formed conical bore, 45, which is in exact axial alinement with the tip, 38, and the tube, 37. Attention is called to the slight enlargement or flare, 45, at the inner. end of the bore, 45. A bridge arm, 42', that is integral with the plate, 42, contains a central bore, 4 which holds the nozzle, 38, in axial alinement with the tube, 37, and in firm abutment with the end thereof. I have thought it unnecessary to refer in detail to the several bolts and flanges whereby the several members are joined. The forms, dimensions, and relations of the parts, 37, 38, 45 and "45, will be explained in the course of the description of the process which I carry out by aid of theapparatus depicted.

My novel process is capable of very brief explanation, as follows: By meansof a suitable Inili, 6, the ore as it comes from the mine or dump is pulverized, granulated or powdered with substantial uniformity. The degree to which pulverization should be carried is determined by the character of the ore, but in many-cases it is suflicient if the pulverized ore is fine enough to pass through a twenty-mesh screen; and in practically all cases a pulverization corresponding to a forty-mesh screen will prove sufli cient. Finer pulverization ordinarily is too slow and too expensive and also makes a slower precipitation of the ore. Obviously, part of the ore will be reduced to a still finer state, leaving the larger particles of the maximum sizes indicated.

Compressed air from the blowing en ine, 16, flows through the nozzle or gun, l5. Ihe pulverized ore which is furnished by the mill is fed into this stream of air and taking on approximately the velocity of the stream of air is thus ejected or discharged from the gun, 15. In practice a substantially uniform velocity is imparted to every particle of the ore, and all of the particles leave the mouth of the gun or nozzle, 15, at a substantially uniform and very high velocity. The velocity thus imparted would afford each particle of the ore a maximum trajectory of many tlmes the length of the shed, 4, were it not for the force of gravity and the baffling or interferingeifect of the air or atmosphere in the shed. Due to such impedance, the lighter particles of gangu e are caused quickly to lose velocity and .to settle upon the concentrating floor at points not far remote from the mouth of the gun, 15. Particles of metal, on the other hand, being heavier, for a longer time resist the impeding action of the air and carry nearly or quite to the end of the shed before settling upon the floor. Other particles of gangue which are burdened with small particles or the purpose of accentuating the reaction of the .air in the shed against the particles, whereby T secure a clear and distinct separation of the particles according to respective masses and shapes, and enable even a very slightly burdened particle of gangue to penetrate the shed to a point beyond that to which the largest particle of unburdened gangue can proceed. With this as a measure of required service of the gun, it is a simple matter to ascertain the degree to which the ore needs be pulverized and the pressure of air which needsbe maintained in the nozzle or gun.

In dealing with ores which contain several metals in a native or pure state, or substantially such so far as concerns the respective speclfic gravities of .the several metals or metal compounds, it is possible by the describedmeans to secure a closely approximate clear separation of the several metals upon the floor of the space or hopper, 20. This 1 have indicated by showing, in dotted lines, several separate troughs or hoppers, 20', in the floor portion, 20. Beginnlng at the far-end of the shed, these troughs may be taken to re resent a series of metals of different speci c weights, such as platinum, gold, lead, silver, etc. However, as a rule, it is sufficient to collect all of the-rlch or heavy concentrates in the'hopper or floor section, 20, leaving to the 'metallurglst the usual task of refining and separating the same by chemical means, with or without the aid of heat. It will be understood that the great bulk of the pulverized ore, to-wit, the gangue proper, hopper, 18. The discharge of the hopper, 18, may be through the waste condult or tunnel, whence the gangue is removed to a spo l bank. The low grade or poor concentrate is deposited in the intermediate hopper, 19,

from whence it may be taken for direct reduction by the metallurgist; but preferably 1 discharge the poor concentrate into the re-- turn duct, 19, and thence carry it back to the mill, 6, or to a separate mill if desired, to be re-ground, and again projected through the concentrating gun or nozzle, 15, whereby a further separation of the metals-from the gangue is secured, with a view to lessening the work of the metallurgist. Obviously a considerable volume of air is discharged into the shed, 4, and while it is desirable to maintain a slight pressure therein, whereby to increase the impeding action of the air upon the projected particles from the gun, there is of course a practical limit which must be observed, both to avoid disis deposited in the large-- ruption of the walls of the shed, and a too great back pressure at the mouth of the gun;

hence the provision of the valved vent or' vents, 21, whereby a substantially constant low pressure condition may be maintained in the shed. v To avoid loss of extremely fine particle of metal, the vents preferably are arranged approximately above the gangue hoppers, beyond which point the heavy particles are sure to be projected. This manner of venting the' shed is attended by the advantage of the banking of the air in the closed end of the shed, for the more certain precipitation of the metal particles and heavily loaded pieces of gangue after they pass over the floor sections or hoppers, 18 and 19.

Lest it be thought that this process, entails the expenditure of much force in the compression of air, 1 will explain that an air-gage pressure of considerably less than forty pounds in the gun, 15, accomplishes the projection of the metal particles to-distances of upward of one hundred feet while the gangue particles are seldom found beyond fifty feet, and which thereforeis fully adequate to the accomplishment of the separating or concentrating efl'ec't here described. The apparatus hereinbefore described is admirably suited to the performance of the several steps of my process, being an appa- ,ratus which 1 have devisedfor this specific purpose. 'The operation thereof is as follows: It will be understood that there is a top closure or valve, 10, for each tank, and also a bottom closure or valve, 27, for each tank. When filling a tank from the mill, the valve, 10, is of course open, while the valve, 27, is closed. When the tank, 9, is substantially filled with pulverized ore, the valve, 10, is closed. Thereupon compressed air from the pipe, 17, is admitted to the tank through the -pipe, 22, and preferabl also tot-he top of the tank through a branc pipe, 22". The maximum pressure of the system, say sixty-five pounds absolute pressure, is thus placed upon the material in the tank, 9. Then after closing the discharge valve, 27, of the (other tank, I open the like valve 27 of the tank which has been filled and put under pressure; at the same time opening the valve, 23, belonging to the mixing head,'12, Thereupon the pulvenzed ore under compulsion of pressure in the tank, 9,

and aided by gravity and the exit of air from the pipe, 22,

' the particles suspended in the stream of'air.

- sponding to that pressure.

combining'tube or conical passa e, 35. Due to the shape of this passage,'t e pressure energy of the stream is in part converted into Velocity energy and the particles of ore take on a higher velocity. Entering the communicating pipe, 36, at this velocity, the stream next encounters the second combining tube, 37, wherein the velocity of the particles is again augmented. In consequence, the stream emerges from the tip, 38, at a pressure considerably lower than the initial orstarting pressure, but at a high velocity. To be exact, the pressure at the tip, 38, under the conditions of initial velocity developed approximates fifty-eight per cent. ofthe initial pressure following the law of maximum efilux and has a velocity corre- If it were possible to attain a suficient velocity it might be feasible to project the particles direct from the nozzle tip, 38; dispensing with the head shown thereon, but a stream projected from such a nozzle tip, due to immediate expansion into the atmosphere, setsmp detrimental conflicting movements among the particles, robbing some thereof of the true trajectories which should be given them if the best concentrating effects are to, be secured. The head, 39, which I have invented, and the pressure of air which I use therein, not only suppress this objectional action, but also operate greatly to increase the linear velocity of The first essential of this head comprises the secondary nozzle tip and mouth, 45, in the form of a conical passage, the inner end of which is of the same diameter as the tip openingofthe nozzle, 38, and the large end of which'is outward. The function of this conical passage, whether or not forming a direct, or as shown indirect, continuation of the reversely tapered tip, 38, is to restrict the lateral expansion of the stream of air and thereby necessitate the linear expansion thereof; whereby further velocity' is imparted to the particles after leaving the tip, 38. If. it were not for the outwardly flared passage, 45, the air would be.

permitted to expand abruptly on leaving the tip, 38, and the consequence of such uncontrolled expansion would be the deflection of some of the particlesfrom their direct linear paths. By thus limiting the lateral expansion to that simple degree which directly responds to the drop of pressure 00- casioned by the unrestricted linear expansion, I am able to convert the pressure energy of the stream into velocity energy and motion, which is the force desired for the propulsion of the particles. Thus I secure the highest speeds derivable from the initial or starting pressure at the pumping en ine or blower.

or the best functioning of the outwardly enlarged conical passage or mouth, 45, and for the preservation thereof against the abrading action of the particles of ore, I provide means for two other purposes, towit', means to prevent the lateral expansion or enlargement of the jet as it emerges from the tip, 38, and, second, means to defend the walls of the conical passage, l5, from the impact of the particles of ore which pass through it. These purposes I accomplish through the employment of the air chamber, 4E0, by the employment of a space or gap, 40', between the two parts, 38 and 4a, and by admitting air under pressure to the chamber, 40, through the crack, 43, leading from thespace, 41. The valve, 17, which is included in the pipe branch, 17', is preferably a pressure reducing valve, whereby the maximum pressure in the supply pipe, 17, is reduced in the chamber, ll), and made to equal the static pressure in the stream which emerges from the nozzle, 38. Upon 'opening or freeing the valve, 17, therefore, air is admitted to the chamber, 40, at the stated pressure. This compressed air from the chamber, 40, finds escape in conjunction with and as an envelop for the jet which emerges from the tip, 38. To facilitate the forming of this air-envelop around saidjet, and within the passage, 45, 1 preferably reversely bevel the intake end of said passage, 45, as shown at 45. Obviously the emerging jet cannot expand within the gap, 40, for the reason that it is encompassed by an atmosphere of the same pressure. Obviously also, as the air from the chamber, 40, finds exit through the passage, 4-5, the envelop which it forms upon theinitial jet is preserved directly upon and against the walls of the conical passage, 45. T11 this manner, the initial jet is prevented from expanding suddenly; also, is limited substantially to linear expansion within the passage 45; and the walls of said passage are lubricated by the added envelop 110 or air and thus are protected against abrasion by the particles within the jet.

it will now be understood that air composing the jet is allowed to expand substantially down to atmosphere by the time it 115 emerges from the passage, 45, and though it preserves its velocity, it is robbed of its capacity to disperse or laterally disturb the particles which it contains in suspension. It will also now be understood that by means 120 of the compound nozzle here depicted, l secure a very valuable augmentation of the velocity of the particles of ore and what is of great practical value, secure this effect by the expenditure of little force and conthe internal chamber, 40,

one hand; or an excessive lateral expansion and concurrent lateral d splacement of par ticles on theother hand; wherefore, it is desirable that the exact predetermined shape shall as long as possible be preservedagainst an abrading or cut action which would chan e its shape.

By way 0% example, drawn to accord with a mountain altitude and an atmospheric pressure of ten and one-half pounds, it may 'be stated that an initial pressure of sixtyfive pounds absolute in the blower pipe 17, and hence at the openings of the pipes, 22 and 23, affords a pressure closely approximating thifty-eight pounds absolute at the tip, 38; and in such cases the reducing valve, 17, is adjusted to maintain the same pressure, 'to-wit, thirty-eight pounds absolute in of the nozzle head.

Under these conditions the conduit between the elbow,.1d, and the tip, 38,'may be re duced to a length inches, and yet admit of the attain-mentor maximum'velocity by the particles therein. ln practice, I prefer that this dimension shall be increased one or more times as a factor for safety as well as for mechanical convenience. With the equipment shown and at the pressures indicated, the air 1s expanded substantially to atmosphere on emergence from the nozzle, 45, and to the particles held in suspension therein, there 1S 1111- parted a substantially uniform velocity of about seven hundred feet per second.

My invention is not, limited to the employment of air as the vehiclefor carrying and expelling the pulverized material, for it will be evident that compressed gases may be substituted; and likewise superheated steam may be used with substantially the same results as the gun or nozzle is concerned, but with the disadvantage of a wet concentrating shed due to the condensation of the steam therein. l desire also that it shall be understood that my invention is applicable to materials other than ore.

As used in the claims the term separating velocity means a velocity such that when the material is projected against a,

given atmosphere, a clear separation between the particles is obtained according to mass and size, articles of small mass and size being foun relatively close to the point of projection and thoseof relatively large.

mass and size being found in a remote positlon.

In the claims the term separation atmosphere means the atmosphere into which the ore stream is discharged for separation of the particles.

of approximately eighteen ticles is prevented.

rious particles of a tion atmosphere.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

l. The improvement in the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a given velocity and static pressure, discharging same into a confined atmosphere having substantially the same static pressure as that of the discharging stream, whereby lateral dispersion of the ore particles is prevented, thereafter converting said static pressure of the stream into kinetic energy, thereby imparting high velocity to the ore particles and in issuing the high velocity stream against the separation atmosphere.

2. The improvement in the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a given velocity and static pressure, discharging same into a confined atmosphere having substantially the same static pressure as that of the discharging stream, whereby lateral dispersion of the ore particles is prevented, thereafter converting said static pressure of the stream into kinetic energy, thereby imparting high velocity to the ore particles and in issuing the high velocity stream against the separation atmosphere in the form of a substantially unidirectional jet.

3. The improvement in the art of corn centrating ores that consists in initiating an orc particle laden aeriform stream at a givenvelocity and static pressure, discharging same into a confined atmosphere having substantially the same static pressure as that of the discharging stream, whereby lateral dispersion of the ore particles is prevented, thereafter converting .said static pressure of the stream into kinetic energy, thereby imparting high velocity to the ore particles and in issuing the high velocity stream against the separation atmosphere at substantially separation atmospheric pressure, whereby'lateral'dispersion of the ore par- 4. The improvement in the art of concen-' trating ores that consists in initiating an ore particle laden aeriform stream at a given velocity and static pressure and with the vagiven stream-cross section all moving at substantially the same velocity, thereafter greatly increasing the velocity of the ore stream, meanwhile maintaining the substantial equality of movement of the respective particles cross sectionally of the stream, and 1n issuing the high velocity ore, stream against the separa- 5. The improvement in the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a given velocity and static pressure and with the various particles of a given stream cross section all moving at substantially the same velocity, thereafter greatly increasing the velocity of the ore stream, meanwhile maintaining the substantial equality of movement of the respective particles cross sectionally of the stream, and in issuing the high velocity ore stream against theseparation atmosphere in the form of a substantially unidirectional jet.

6. The improvementin the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a given velocity and static pressure and with the various particles of a given stream cross section all moving at substantially the same velocity, thereafter greatlyincreasing the velocity of the ore stream, meanwhile maintaining the substantial equality of movement of the respective particles cross sectionally of the stream, and in issuing the high velocity ore stream against the separation atmosphere at substantially separation atmospheric pressure.

'3. The improvement in the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a velocity of several hundred feet per second and at a given static pressure, discharging same stantially the same static pressure as that of the initiated stream, and thereafter increasingthe velocity of the ore particle laden stream to upward of 500 feet per second and in issuing same against the separation atmosphere in the form of a substantially unidirectional jet.

'9. The improvement in the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a velocity of several hundred feet per second and at a given static pressure, discharging same into a confined atmosphere having substantially the same static pressure as that of the initiated stream, and thereafter increasing the velocity of the ore particle laden stream uplocity of several hundred feet per second and at a given static pressure, discharging same intoa confined atmosphere having substantially the same static pressure as that of the initiated stream, and thereafter increasing the velocity of the ore particle laden stream to one of at least 700 feet per second and in issuing it against the separation atmosphere.

11. The improvement in the art of COI1C1I trating ores that consists in initiating an ore particle laden aeriform stream at a velocity of several hundred feet per second andat a given static pressure, discharging same into a confined atmosphere havingsubstantially the same static pressure as that of the initiated stream, and thereafter increasing the velocity of the ore particle laden stream to one of at least 700 feet per second and in issuing it against the separation atmosphere n the form of a substantially unidirectional 12. The improvement 1n the art of concentrating ores that consists in initiating an ore particle laden aeriform stream at a velocity of several hundred feet per second i and at a given static pressure, discharging same into a confined atmosphere having substantially the same static pressure as that of the initiated stream, and thereafter increasing the velocity of the ore particle laden stream to one of at least 700 feet per second and in issuing it against the separation atmosphere at substantially separation atmospheric pressure.

13. The improvement in the art of concentrating ore that consists in initiating a low velocity ore particle laden aeriform stream, thereafter greatly increasing the velocityof the ore particles and discharging them against the separation atmosphere, and in maintaining the ore stream against lateral dispersion While it is being accelerated and as it discharges into the separation at mosphere.

In testimony whereof I have hereunto set my hand this 2d day of March, 1918.

FERDINAND G. GASCHE.

Images