US2077332A - Process of and apparatus for amalgamating and separating metals - Google Patents

Description

April 13, 1937. -w KROLL 2,077,332

PROCESS OF AND APPARATUS FOR AMALGAMATING AND SEPARATING METALS Filed Feb. 19, 1934 s Sheets-Sheet 1 E Q 6 N 1 I \11 W on a: N 2 I a E I O [W Ill Mai-fin 100, .BY

ATTORNEYs P" 1937. M. w. KROLL PROCESS OF AND APPARATUS FOR AMALGAMATING AND SEPARATING METALS Filed Feb. 19, 1934 3 Sheets-Sheet 2 ATTORNEYS April 1937. M. w. KROLL 7,332

PROCESS OF AND APPARATUS FOR AMALGAMATING AND SEPARATING METALS Filed Feb. 19, 1934 3 Sheets-Sheet 3 ZZ, INVEIQTOR ATTO RNEYS ammo arm scrim-Anna mars w. Kroll. 1mm. Application February 19, Serial a. 112,026 a mm; (or. flit-1.5)-

The invention relatesto a process of and apparatus for, amalgamating and separating metals.

The primary aimof the present invention is to providea process of and apparatus of this char- 5 acter wherein in their use for the purpose of extracting metals from finely ground ore, they.will

enable the finely ground ore to mu; with'the solution in the proper ratio to keep the mass in a fluid or liquid state and the resultant pulp comprising the pulverized ore and solution will be sustained in a state of agitation so that all ore particles will be suspended tov theextent that no settling will occur at the bottom of the vat, the rate of agitatiori being, of course, varied in ac-' cordance with the specific gravity of the material under treatment.

Another object of the invention is the provision of a process of and apparatus of the kind specified, wherein the agitation which'is neces- 0 sary to keep the mineralv particles in the solution suspended may be produced by utilizing a down-draft propeller, mechanically 'driven at the properfspeed, and in some instances, it may be found necessary or. beneficial to utilize the "propeller for disintegration of material, this being 1 had by perforating the propeller blades. The disintegration action is found especially beneficial in freeing extremely fine gold from clay, the.

action of the propeller producing a constantly moving stream of material with a downward motion, while itis also possible to utilize an electric current of the properv'oltag'e, current density and frequency for "the production of electrical precipitation, separation or amalgamation of the. metallic particles-while. suspended and under agitation, these particles being deposited on acathode or electrical-conductor plate disposed, in the bottom!!! a-vat and of such material or composition as to produce the desired result in connection with the mineral under treatment.

- A further object of the invention is the pro vision of a process of and apparatus for amal gamating' or"extracting ores or metals, wherein the solution used in connection with the ore under 45 treatment be of such a chemical nature as to produce -a-condition which will aid in bringing ,4

about extraction-of the desired metals and the electrical resistance of the solution controlled by the addition of salts, acid or alkali in the correct 5o proportions tobring abouts desired 'state of conductivitydn the solution and also that will, in many instances, produce chemical changesin the material undertreatment so 'tnatthe timeiof 7 treatment, the cost of electric current, andthe as percentage of abstraction obtainable canbe made more favorable. In some instances, theuse of a chemical reagent makesit possible to so change the chemical composition of the material under treatment that although "it may be partially or entirely refractory in its original state, the al 5 teration in the nature of the material will en'- able the same to yieldto the process.

In the accompanying drawings:

Figure 'l' is a sideelevation of the apparatus constructed in conformity with the invention and employed in carrying out the process of amalgamation and separation of ores. 1 1 Figure 2 is a vertical longitudinal sectional view thereof.

Figure 3 is a vertical transverse sectional view 15 taken on the line 3-3 of Figure '2 looking in the direction of the arrows.

Figure 4 is a view similarto Figure 3 showing a slight modification of the apparatus. 1

Similar reference characters indicate corresponding parts throughout the several views in 20 the drawings.

Referring to the drawings in detail, particu; larly Figures 1' to 3 inclusive, the apparatu s for the amalgamation and separation of ores, as constructed in conformity with the present invention, comprises a substantially V-shaped agitatingvat- A which includes the opposite vertically disposed spaced parallel sidewalls L5, these being joined in any suitable manner with upwardly 3o divergentspaced end walls 6 for a hopper iormation of the vat. Beneath the said vat is a combined settling and filtering vat I, the same beingdl videdat an intermediate point by a vertical partition 8 to provide the settling chamber 9 and the filtering chamber 10, respectively', the partition being formed with a filtering screen ll.

of any approved construction, 80 that the liquid or fluid passing from one chamber to other filterli,.aswillbe obvious. ,r

Risingfrom the vat l 'at one side of the vat A' a will be subjected to the filtering action of the 40 are suitable supports lrfor a platform IS on which is arranged a pump ll of the motor or hand driven type having the lift pipe or cylinder li-which-extends'withinthe chamber 9, so that its contents can be retumedZto the vat A, the'delivery of the liquid from the pump 14 into the vat A being had throughthe discharge spout I.

of saidpump ll. l 5 Mounted in suitable bearings ll arranged near the top of the vat A, at one end thereof, is the shaft it of an agitator'naving the propeller blades 1! of'the'form t'o effect'a down draft within the said vat A, theshaft I! of theagitatou: Mini disposed at the same inclination of the end walls 6 of the vat A next thereto. Suitably supported upon the vat A is an electric motor 20 which,

through the pulleys 2| .'and belt 22, respectively, has connection with the shaft l8 of the agitator so that the latter'will be driven directly from curialcolumn of the cathode 23 being indicated at 29 within the vat A. i

In the process for the extraction of metals by electrical amalgamation and separation, the apparatus is employed and for the purpose of extracting metals from finely ground ore, the finely ground ore is mixed with a solution in the proper ratio to keep the mass in a fluid or liquid state 2 and such ore and the solution is admitted into the vat A so that the pulp comprising the pul-' verized ore and solution will be mixed and kept in a state of agitation by the agitator, whereby all ore particles will be maintained in'suspension to the extent that no settling will occur at the bottom of the vat A. Of course,the rate of agitation is varied in conformity with the specific gravity oi the material under treatment and such agitation is essential. to keep the mineral particles in the solution suspended,"the agitation being in a downward direction, the propeller blades l9 being located beneath the ,level, of the solution or the mixture as contained within the vat A and the agitator producing a constantly 40 moving stream of material with a downward mo tion so as -to bring about an intimate contact of f all particles suspended-with the bottom of the vat.

By using the down draft, force of gravity is utilizedv in helping to bring all particles sus-' pended in contact with the bottom oi the vat A and in combination therewith it is possible to. use electric current to assure electrical precipitation, separation or amalgamation of the metallic particles suspended in the vat A at the time or I agitation and to deposit these mineral particles on the cathode located at-the lowermost point of the vat A. The anode 28 for conducting the electric current is so placed in the vat that the exposed area in contact be varied to meet specific requirements. Furthermore, the distance of air gap between the anode and the cathode maybe varied by the adjustable members 30 for regulating current density, and the material comprising the anode and the cathode is to be of a composition which will prevent excessive disintegration of the anode, the cathode material being determined by the material to be treated. a

within the vatA is controlled by the additioifof salts, acid or alkalies in the correct proportions to'bring about a desired state of conductivity in the solution, as well as in many instances to pro- 'zo-iiuce chemical changes in the material under treatment, so that the time of treatment, the

costof electrical current e action obtainable can be made more favorable. j .It is also possible to bring about-a complete with the solution may' The electrical resistance of the solution as used and the percentage of extraction of the desired metal. from a continuous fiow through the vat by the use of. a chemical reagent, the incoming feed of pulp to the vat A and the discharge rate being regulated in accordance with the time required for satisfactory extraction from the material under treatment.

In one side wall 5 of the vat A is arranged a gate valve ill, the same being disposed approximately one foot above the extreme bottom of thesaid vat and this valve being utilized to facilitate discharging the pulp after satisfactory extraction of the metals in the material under treatment. The material in the vat A is kept in a state of agitation during the period of time requiredfor discharging the tailings and the fresh solution being pumped into the topof the vat at the samerate that the solution is drained off through the discharge valve 3|, the pump H being actuated to deliver the fresh solution into the vat A. The valve 3 l'has connected thereto a flexible pipe 32 for the discharge from the vat A to be conveyedjnto the settling chamber Ill and through the instrumentality of the filter II the liquid contained in the tailings from the valve 3] will be admitted to the chamber 9 of the vat 1, while' the ore carried in suspension by the liquid will be deposited in the chamber it, it being-apparent that thesolution when passed through the screen II will be reconditioned to bring it back to a clarified state to be used again in the agitating vat A. The exhausted ore after having .been treated for extraction is removed from the settling vat in any suitable manner, preferably by the use of -a sand pump (not. shown) or by any other mechanical means which excludes the removal of the liquid reagent, thus confining the loss of reagent to that which is carried out in the form of a moisture contained in the pulp.

By reason of the formation of the propeller blades IQ of the agitator, when the same is in operation, a suction is created above the position of such blades which has a tendency to sink all mineral particles which might have otherwise a tendency to fioat on the surface of the solution due to the surface tension of the solution used.

The angle of the shaft i8 of the agitator with relation to the angle of the vat is such as to create a downward movement of the solution on the side of the vat where the propeller shaft is located and an outward motion of the solution in the opposite side of the vat, -thus keeping the.

solution-with its suspended material in a rapid state of circulation in the vat A in order that the cathode in the bottom of thevat will be continuously bombarded with the mineral particles which tion.

Included in the electric circuit for the cathode and'a'node is an ammeter 33 and a rheostat 34, respectively, these being mounted directly vat A, thus making it possible to measure and control the current density used in the extraction process.

It is, of course, understood that the chemical reagents, as well as the electric currents, used with the apparatus'in amalgamation and separation by the process are many and must be changed in order to bring about a satisfactory extraction of the desired metal or metals from each specific type or variety. of ore of which its chemical or mechanical structure may warrant and the principles of using chemical reagents are to make the suspended solution in the vat an elec-' trolyte, so that the nietals in the solution will assume a positive electrical charge from the anode on the are in a state'of suspension in such solu-. 7

and thus be passed to the cathode or to bring about a complete or partial ,chmical change in the ore under treatment, or to dissolve partially or completely the metals and converfthem into.

5 soluble electrolyte-salts so that they may be precipitated at the cathode by the electrical current, or to dissolve undesirable metals and make them non-electrolytes so that they will not interfere with the completion of the process. The specific 1o reagents for the leaching of the metals and the formation of electrolyte saltsthat they may be precipitated at the cathode by the electric current may be potassium hydroxide; potassium chloride; ammonium hydroxide; sulphuric acid;

hydrochloric acid; nitric acid; potassium nitrate or sodium nitrate; potassium bichromate; cyanide potassium or potassium sodium and calcium;

- barium hydroxide; calcium hydroxide and potassium carbonate or calcium carbonate or sodium carbonate.

A reagent may be used to counteract an undesirable' condition existing in'the ore, such as a strong acidity or alkalinity that maybe unfavorable and by the addition of a counteractor bring about the desired condition forthe extraction of the metal or metals. This reagent should be called a sizer or conditioner which could be used as an electrolyte or just bring the ore pulp to a neutral condition and the addition of a beneficial 3 reagent to bring the conductivity of the solution to the desired point.

In Figure 4 of the drawings there is shown a slight modification of the apparatus wherein the vat B, at its lower point,'has fitted therein an auger 35 having the extended shaft 36 for attachment to a mechanical drive for the rotation thereof and this auger is used for the discharge .of concentrates or mercury as may be within the lowermost portion of the vat B, in event that the vat is used .as a continuous type concentrator, as will be clearly apparent, the auger housing 31 being formed with a downwardly directed discharge spout 38 for communication with the lowermost vat of the said apparatus.

The V shape of the vat utilized in the process has an important bearing not only upon the recovery of desired mineral but also from a standpoint of discharging tailings. The position of the propeller with its downward motion creates a circulation of the mass or material under treatment on the side that the propeller is located and an upward movement on the opposite slope. It will be noted that the tailings discharge outlet is located in the approximate center of this circulating mass of material. This is very important where mercury is being used as a cathode because if the discharge outlet were located in the propeller slip stream, there would be a tendency to carry over mercury in the discharged tailings.

Another important feature is the fact that in an ore that carries mineral in a finely divided state, it is absolutely essential to have this circulating action of the entire mass under treatment to prevent accidentalflotation of the mineral particles on the surface of the solution in use in the vat. So it becomes'quite evident from the above that the particular shape of the vat is quite important a so far as the entire process is concerned.

What is claimed is: I An apparatus of the kind described comprising a downwardly tapered vat closed at its lowermost smaller end and open at its top for' receiving comminuted ore and a solution, bearings fixed to the side wall of said vat at the open top thereof, a. rotatable shaft journaled in said bearings in close parallel relation to the side wall of said vat and having an agitator head located close to the bottom end of the vat to be deeply submerged in thesolution therein for causing-a continuous unrestricted down flow of the solution in the direc tion of the lowermost end of saidvat and a circulation in an upward direction at the side of the vat remote from said head, atray beneath the vat and having a vertical partition dividing it into independent compartments, 9. screen asso-- ciated with the partition at the upper edge of the latter, a pump operating in one of the compartments for'transi'erring substance therefrom into the vat, a mercurial pocket formed at the lowermost end of the vat and containing mercury, a drain-from 'said pocket, .an anode fixed to the side of the vat interiorly thereof and removed from the level of the mercury in the pocket, and

a lead from the vat to the other compartment and positive and negative current leads to a direct current supply from said mercury and said anode.

MARTIN W. KROLL.

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