USRE17757E - J e hopkins - Google Patents

Description

July 29, 1930; Re. 17,757

APPARATUS AND METHOD FOR REGOVERING PRECIOUS METALS ksheets shsgt '1 Original Filed June Jwumlioz APPARATUS AND-METHOD FOR RECOVERING PRECIOUS METALS 2 Sheets-Sheet 2 ea (5. fl pkina.

J. E}. HOPKINS Original FiladJune 21, 1926 July 29, 1930.

Reissuecl July 29, 1930 JAMES E HQPK TN 0E DENV R, CQLQI AD THE NASQEN'I AMF A QQBRQBATIQN,

SSEGEIQRJ BY A SIQNMENT$s IQ OF DENVER, COLORADO, A oonronn rron ABIEABATUS AND METHQD FQIR; RECQVERING PREQ'IQ'US, MEIAL S Mginal No. 1,678,142, dated July 24, 1928, Serial No. 1175383., filed June 21, 192.6. Applioatiqn to; reissue flIed Jenuary12; 1930. Serial HQ. 419 607 his inven ie re a es n imp o men in.

apparatus. and method its o e ng go d and platinum Values from aur-iterons and plati-niferous materials and end It s Well kn wn o: thos er ed. in his art that gold will quite r dily form a mailge s, wit me susy on quicks l e n it s equally Well known that platinum will, net, for-m; an ama gam- It has, therefo e, been pos e tov recover gold a ues m s w ich p rmit the go d to come inte direct contact with mercury, but this hasv failed to, save the platinum values which are often of g eater value an the. gold,

When sodium is added to quicksilver, it intensifies the action thereof and greatly in? creases. its afiin ty' or g d he o um amalgam also has an affinity f r plat um so that if the latter comes into; contact with it, it will be. amalg m t d T i is be ed to be due to the fact that there, is, an afinity between the sodium and the platinum, which causes. the sodium to form c at g o t e. platinum part cles nd, s ce he e is a st ong afiinity betwee the mercu y and e o um, the sodium coated particles of platinum will combine with. the ercury- It is. e t that if a sodium amalgam containing platinum is subjected to some treatment that will remove the sodium the platinum Will separate from the. mercury, This is taken advantage oi and the sodium platinum amalgam is subjected tothe action of; Water which combines with the sodium, forming sodium hydroxide and hydrogen (Na +H2Q NaOI-I H).

It is. an Object of this invention to produce a machine for the recovery of gold and platinum Values Which shall be so constructed that it will continuously renew the sodium in the mercury so as to provide a continuous supplyof sodium amalg m hi h is th delivered to the amalg m i g e c o eparato This production of sodium and nascent sodium amal am is produced by electrolytic means in t 1e manner to be presently described.

My invention can be most clearly described and Will be most readily understood when reference is had to the ac mp ying drawings nuhich the Pref r d whe iment st an a e a e p acti ng th i ve iqnhes b eni u tr ted a d in which F gure 1 isa tepplan view of e ombined unelg me e and sodium m ga genena :or- Figure 2 s. s ction ta en on: ine, 2:21 H we 1-, a

figure is a s ctiqii. aken Q11. line :3,- Eig'ur F gure is a di metrice se tion 0f the me cury ank de ignated 5 i th dra ing as t ken: on l ne F gu e 2- Figu e 5 s a s ction tak n 11 in Fi ur Figure 6- is. a w ring diagram; d F gure 7 is a long tud nal, sec ien hreugh one of the lectroly ic cells and i taken on line 7-7, Figure In th aw ngs he s ippert ng ram erk ha be e ig at d. as. who y the nusmeral 1 s there appea s to be. no ne essity ord ntifyi g al e h parts t ere Sun: por ed by t is fram erk is s rec pt qr hopper 2wh ch o ains th P lp cb t eat ed; a. ute 3 extends r m one si e 0f he on-per 2. and, its bottom may be form dy an exten io of th bo om th hopper, The. wa l s of t e h pper-ha t l redse pa ed r m. h b t om s as t p ev de w slot 5 through which the pulp may flow. An adj tabl g 6 er es. b: de er ne he rate at which he pu p flow rom he o er en oi 'the ch te i Located di ectly b lcw heend f chut .3 is a recovery table preferably consisting of a copper pla 7 hose upp r s has e amalgamated if des e The pier end f he plate 7 is. bent upward y i t e manner indic t by nume al 8 sQ s to pre ent leak age a d ts s d s are secu ed to. the side p e e 9- e d Q-r T e lew dge. o he P te 7 res s en the p f he upp all c the t ough 1.1 nd iscurved do wa dly in the manner indicate a 2- A e ts ba 13' s: t nds bet en he side 9 nd 10 dire tly ver the center line of the l'fl igll 11 and serves to force the pulp to pass down under and against the sodium amalgam hose upper su t cs i i d a ed by in 1% n F gu e After passing underneath the baffle bar 13,

thepulp flows over the edge or apron ofv the trough 11'and onto the-plate 7A which 17 which serves as a reservoir for a solution of sodium chloride. This tankhas a faucet 18 which is located directly above the electrolytic cell 19. This cell has as carbonanode 20 which extends longitudinally thereof and is connected with the positive pole of a direct current source 21 (Figure 6) by means of a wire 22. The cell contains a quantity of mercury 23 which is connected to the negative pole of the current supply by means of the conductor 24. A launder 25 is secured at its upper end to the lower wall ofthe cell 19 and serves to carry the brine from cell 19 to a similar cell 19A that is located at a lower level. It is the intention to have the same number of electrolytic cells as there are plates 7 although itis possible to have a single cell for serving a plurality of plates. The lower'cell has been designated by 19A and the other elements are indicated by the same reference numerals as the corresponding elements in the upper cell but to which the letter A has been added. .From the lower cell 19A a launder 26 extends to the reservoir 27. A pump 28 which is operated from power derived fromthe motor 29 has its intake port connected with the reservoir 27 by means of a pipe 30 and its outlet port connected with the tank 17 by means of a pipe 31. A branch pipe- 32 extends from the pipe 31 tothe reservoir 27 and is controlled by the valve 33. The object of the bypass 32 is to permit the deliveryto tank 17 to be regulated sothat the level of the brine will remain substantially constant. v I v v A tank 34 is supported on the framework 1 at a point above the level of the mercury in the uppermost cell 19 and serves as a res ervoir or supply for the mercury. A pipe 35 communicating with the tank 34 has a branch 37 which extends to the cell 19 and is controlled by a valve 36. A pipe 37Aleading to the cell 19A branches from the pipe 35 and is controlled by a valve 38. 'VVhen the machine is in operation, mercury will flow from the tank 34 tothe cells 19 and 19A and the rate of flow will be regulated by valves 36 and 38.

Referring now to Figure 7, it Will be seen that the cell 19A is provided with an opening 39A at one end and near the bottom. A pipe 40A. is connected with this opening and: hasanupward bend 41A which determines the level of the mercury which must be a short distance below the lower edge of the anode 20A. Pipe 40A extends over onto the plate-"TA where it terminates in a perforated section 42A. This section of'pipe has its outer end plugged and is provided with a plurality ofsmall holes43A which are located on top and through which the mercury escapes onto the plate 7A, thepipe being lo cated beneath the apron 15 and in close proximity to the surface of the plate so as substantially toavoidfiouring of the mercury delivered therefrom, thereby preventing material loss in mercury and values with the tailings. From the cell 19 a'similar pipe 40 extends. The corresponding parts of this pipe have the same reference numerals as those given above, but with the letter A omitted.

Referring now more particularly to Figure 5', it will be observed that the bottom or trough 11 is inclined from the ends of the middle point, which has been indicated'by numeral 44. A hole extends through the bottom at point 44 and to this a valve 45 is connected.

A pipe 46 extends fromthis valve to the clean out 47 to whose lower end or-bottom a stop cock 48 is secured. A pipe 49 has its lower end connected with the clean-out 47 and its upper end bent into a gooseneck 50 whose height determines the level 14015 the mercury.

The end of the gooseneck terminates over the inclined trough 51. o

The lower end of the trough 51 has an open ing 52 from which a pipe 53 extends downwardly and terminates a short distance be- 'low the upper end of the tank 54. A conical canvas strainer55 is securedto the upper, end of thetank 54 in the manner shown in Figure 4. A drain cock 56 is connected to the bottom of the tank 54 andis employed when the tank is to be drained.

From the tank 54 a pipe 57 extends to the pan 58 which can be subjected to a spray of water from the pipe- 59. From the pan 58 a pipe 60 extends to the mercury pump 61,

which is driven from the motor 62. This pump discharges the mercury through pipes 63 and 64 into tank 34 from which it flows into the cells 19 and 19A.

Let us now assume that the parts are assembled in the manner shown and described and that the hopper 12 is filled with pulp, meaning pulverized ore mixed with water containing metallic gold and platinum; that tankl'? is filled with a sodium chloride brine and that tank 34 contains mercury. The generator 21 is connected with the anodes 20 and the mercury cathodes 23. The faucet18 is opened and brine is allowed to'flow. 1 This brine fills the cell 19 and overflows onto the launder 25 [mm which it enters the cell 19A and from suitable means (not shown). The sodium readily combines with the mercury and forms a sodium amalgam. The intensity of the electric current and the rate of flow of the mer-- cnry is adjusted so that when the mercury leaves the cells it will contain about three onehundredths of one per cent of sodium. The sodium amalgam now passes through th pipes 40 and 40A and elnergingthrough the holes 43, 43A, falls upon the respective plates 7, 7A, establishing upon each of the latter a bed or coating which gradually moves down over the surface of its plate. The sodium amalgam passing over the plate 7 delivers into the trough 11, while the amalgam flowing over the plate 7A delivers into the trough 11A. The wet pulp flowing from the chute or launder 3 impinges directly on the bed. of alkali metal amalgam flowing over the plate 7 at a region where the amalgam is substantially free of overlying matter, thus promoting penetration of the surface film of the flowing amalgam bed and better envelopment and amalgamating contact of the solid particles of the pulp with the amalgam. Similarly the pulp which overflows from the trough 11 and passes over the edge or apron 15 of the latter falls directly on the bed or" amalgam on the plate 7A at a region where the amalgam is relatively tree of overlying matter. When the pulp delivered from the launder 3 or overflowing from the trough 11 impinges upon the sodium amalgam flowing over the plate or the plate 7A, as the case may be, the water 01" the pulp combines with the sodium and forms sodium hydroxide which is a powerful cleansing medium that removes any oily film from the gold and platinum, whereby the metal itself becomes e3:- posed so that itwill have good contact with and be acted upon by the amalgam. The chemical change which occurs when the water of the pulp reacts upon the sodium amalgam also has the effect of greatly decreasing the surface tension of the flowing bed of amaigam and thereby contributes to the more effecmve envelopment and amalgamating contact of the metallic particles of the pulp. In its course through the apparatus the pulp flows from the hopper 2 through the chute 3 and is delivered upon the bed of amalgam flowing over the plate 7. At the lower end of this plate the pulp enters the trough 11 and passes underneath the baflleblock 13 therein, thence delivering over the edge or apron 15 of the trough 11 and falling upon the'surface of the amalgam bed which is flowing down over the plate 7A. At the lower end of this latter plate the pulp delivers intothe trough 11A and after passing beneath the battle block 13A therein flows into the chute 16. Upon passing beneath the bafiie plates 13, 13A, the pulp is forced against the surface of the amalgam so that the lattercomes in contact with the gold platinum. The greater part of the values are recovered on the uppermost plate and by using several plates in series a thorough recovery can he obtained.

As the amalgam flows from the troughs 11 and 11A, it passes through the respective pipes 46 into the corresponding clean-out traps 4L7 where the values of gold and platinum settie to the bottom due to their great density. The mercury passes from the traps through pipes 49 respectively leading there- 33011! and flows into the trough 51 and down into the canvas. strainer 55 where any large particles are separated. The mercurythat passes through the canvas strainer enters the tank. 5% where further separation takes place and from which the settlings may be removed through the cock 56. The lighter mercury or sodium amaigam flows through pipe 57 to the pan 58 where the action of the water spray removes any trace of sodium that may stillbe present and since mercuryalone has no aiiinity for platinum, any platinum which may be present, when. the amalgam enters pan 58 will immediately be released and will settle to the bottom. If any gold or platinum still remains after the mercury returns to tank 34, it will stay in the mercury stream until it settles to the bottom in some one of the several clean-out traps.

-' I want to call particular attention to the fact that there is a continuous supply of nascent sodium amalgam which is supplied to the separator, and which, when subjected to the action of the water in the pulp, results in the production of sodium hydroxide which dissolves any grease or fat that may be on the metal particles.

The sodium amalgam, above explained, is more active than mercury andhas the prop erty of combining with platinum so that these values will he recovered. This, therefore, makes this apparatus and method very valuable in platinum mining as it has heretofore been very diiiicult to recover the platinum.

Having now described the invention what is claimed as new is:

1. In combination, a plurality of amalgamating plates in tandem, means for flowing pulp containing values over said plates in succession, a means for preparing alkali metal amalgam and means for conveying means independently to the head of each of said plates and'distributing it thereover.

2. In combination,; a plurality of amal gamating plates in tandem, means for flow ing pulp containing values over alkali metal amalgam, means for conveying said 'amalgam'di-rectly' from said preparing preparing means independently to the hcad f means independentlyto the head of each of said plates and-"distributing it thereover, and

a trapbetween'each two plates for catching i an d (allow- I a flowing bed of alkal1 metal amalgamupon the mercuryand'metal amalgam ing the pulp stream to pass on.

3; In combination a plurality of inclined amalgamating plates in tandem, means for flowing pulpover-said plates in succession, a conduit for sodium amalgam transversely arranged at the head of each plate and open to allow the amalgam to 'pass' to the plate, means for protecting said conduit from the pulp stream as it is fed to the plate, means said plates-insuccession, agmeans for preparingand flow asa thin sheet with the amalgam bed and thereafter causing the pulp to come into contact, with additional vcontinuously flowing alkali'metal amalgam.

a flowing bed ofalkali metal amalgam upon a surface, and causing wet pulp containing:

The process that consists inestablishing values to impinge upon the upper surface of theainalgam bedat a region where the latter is substantially free of overlying matter and to flow with said bed. v 10, The process that comprises establishing a surface and causing wet pulp containing upper surface of andto flow freelywith the amal am bed and continuously renewing the strengthof the flowing amalgam.

JAMES E HOPKINS, I

for preparingsodium amalgam and means for conveying said amalgam directly from said preparing means andindependently to said conduit of each plate. 4. In combination, a plurality of incline amalgamatingplates positioned to cooperate so that the material to be tr'eatedymay pass from the tail of one to-thehead ofanother,

means foriflowing pulp containing values over said plates in succession, a means for preparing alkali metal amalgam, and a means for conveying sa d amalgam directly fromsald of each-of said thereover. i p I 5. In combination, a plurality ofamalgamating plate sections positioned tocooperate so that the material to betreated may pass from one to the other, means for flowing pulp plates and distributing it containing values over said plate sections in succession, means for preparing alkali metal amalgam, and means for, conveying said amalgam directly from said preparing means independently toeach of'said plate sections and distributing it thereover.

6; The process of flowing wet pulp over an extended mercury surface and feeding fresh- 1y prepared sodium amalgam independently to the surface in proximity to the point of'delivering" the pulp to said surface, 'andvat a plurality of spaced. intervals along the path of flow'to -maintain the mercury surface at maximum efficiency, 7. The'prccessthat conslsts in aflowing bed of alkali metal amalgam upon a 1 surface and causlng wet pulp containing,

establishing

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