USRE13307E - Process of recovering fine gold - Google Patents

Description

'UNITED STATES rAajInvry OFFICE.

JAMES H. ALLING, OF COLUMBIA, CALIFORNIA, ASSIGNO, BY DIR/ECT AND MESNE ASSIGNMENTS, TO SECURITY AND HOLDING? COMIANY, OF SAN FRANCISCO, CALI- FORNIA, A CORPORATION OF CALIFORNIA.`

Pnocnss 0F nEcovEnrNG FINGoLn Specication ot Reissued Letters Patent.

Reissued Nov. 7, 1911.

Original No. 947,957, dated February 1`, 191D, Serial No. 430,695. Application for reissue led August 15,

1910. Serial No. 577,337.

To all 'whom "Lt may concern.'

Be it known that I, JAMES I-I. Amano, a citizen of the United States, residing at Columbia, in the countyv of Tuolumne and State of California, have invented new 'and useful Improvements in Processes`of Recovering Fine Gold, of which the following is a specification.

The bject of the present invention is to provide a process for the recovery of very fine particles of gold, silver', and platinum.

There are known to exist large natural deposits of gold-bearing material which are comparatively rich in the precious metal,

` but from which the gold cannot be recovered by any known process except smelting; and as the cost of smeltingis from $5.00 to $7.0() a' ton, besides the freight, the cost by smelt-f ing is prohibitive except for very valuable ores. The reason why such gold cannot be recovered by ordinary methods is, either that the particles of gold are so extremely minute, that they float away, and cannot, be arrested in the-ordinary sluices, amalgamal tors, and other apparatus in general usc, or

that the particles of gold are incased in capsules of material which has to be removed by grinding, so that the particles of gold will be separated as free gold, and recovered by amalgamation. But, to do this the material must be ground to such a degree of fineness, say 100 lesh -or smaller, that, in this case also, the ordinary methods of recovering this very tine gold proves impracticable or'too expensive. VIn addition,v

there are, in 4the States of California, Nd` vada and elsewhere, large deposits of tailings from former workings of ore, which tailings contain a large amount of gold, but in such a finely divided state as not to-be recoverable by ordinary methods. many of these dumps, which containing finely divided gold, also `contain such large quantities of copper, iron or arsenical pyrites, and other baser ores, that the ordinary cyanid process cannot be profitably applied thereto, on account of the baser ores consuming too large a proportion of the cyanid. These can be worked by my process.

In the accompanying drawing, Figure l is a plan View, of the apparatus;'Fig. 2 is a broken side view of the same; Fig. 3 is an enlarged broken detail longitudinal section |`rbst'iug on the tops of said sidesw AlSO l of the same; Fig. 4 is a cross section on the l line 4 4 ofFig. 3;*Fig. 5 is an enlarged broken detail longitudinal section through an Aanode plate and mercury pocket.

Referring to the drawing, l indicates a sluice box which is sloped at a reater angle than are the sluice boxes used or the recovery of gold in the ordinary processes. In the bottom of said sluice box is a continuous amalgamating plate 2 formed at suitable intervals into pockets or troughs 3. Each pocket is formed with a rear wall 4 having a considerable slope nearly 45 degrees, to the vertical, a front wall 5 sloping-slightly backward from the vertical, and a bottom substantially horizontal. In each pocketis placed suiiicient quantity of mercury, shown at 7. The sides of the sluice box are formed with oblique grooves 8 inclined rearwardly upward, and across said sluice boxextend anode amalgamating plates 9, with. their edges in said grooves. The lowenedges of said plates extend to within .afshort distance, say E of an inch. from `r`theupper surface of the mercury in the troughs or pockets 3. 'lhe height of each plate'tfan beadjusted bynwans of adjusting screws 10 screwed through lips 11 extending from the plates over the sides of the sluice box, said screws i. Extending along one side of 'tlieislaiice box is an electric conductor 13, coneetedto the positive pole of an electric current'igene'r-- ator 1,4.- r.lhis conductor is connected `by conductors 15 with the several ,plates 9,

wlilchthus serve as anodes for currents of electricity. The conductors 13 and 15 are the current in order to avoid any heating effect. whatever.

In addition to the anode plates 9 there are vprovided swinging carbon anodes 16 suspended froiiiwbars 17 extending across between the tops of the sides of the sluice box, substantially midway between the anode plates 9. In certain cases, it may be desirable to interpose more than one swinging anode between each pair of anode plates. These cross bars 17 are electrically connected to the longitudinal conductor 13. Y

'lhecathode plate 2 is connected by a wire 19 to the source of the electric current.

The material, having been first finely pulrerized, is fed by a chute'23 into the top of the sluice box. At the same time there is fed, by a pipe 24, a suilicient quantity of water, about 4 tonsto I ton of material, and through a about 1 to 1000, 2000, or more parts, ofa mixture consisting of aqueous solutions of potassium cyanid and mercurio chlorid. The proportion of the mixture to the water will vary according to the richness of the material being treated, the rule being to supply, in the mercuricchlorid, one ounce.

. ofmercury to each ounce of gold in the material. y n treating certain ores, I have found satisfactory proportions by Weight to be to 1l lb. mercurio chlorid and gallons of the solution. v The addition of the cyanid facilitates ,electric current passes or through the mercury in mated and the electrolysis and cleans the gold. The from the anode plates and swinging anodes into and through the Water and other material flowing down the sluice box and enters the cathode plate 2 in the bottom of the sluice box, either directly,

` the troughs or pockets 3 thereof. The density of the current used is comparatively low, being from 116 to 1 ampere for each square foot of cathode surface according to the lrichness of the material. For the purpose-of varying the amount of -current for-different material aV rheostat'20 is provided. I have found a voltage of`5 volts to be satisfactory in practice. Anfammeter 21 and volt meter 22 are used to indicate the cu-rrent and volt- .flgei By the above described process l have been able to save over 95 per centum of the values ,of material-containing finely divided gold, which cannot be saved by ordinary processes.

It is ini.I order to replenish the aqueous solution eimer-curio chlorid with mercury that the .surface ot' theanode is amalgasince the mercury is continually being removed from the .rear surface Yof the anode plates by electrolysis as well as by the impact of the particles of gold thereagainst it. is'desirabl'e to replace this mercury as fast as removed, so that there Will always be a sufficient coating of mercury upon the anode plates to obtain a proper action of the-apparatus. Many contrivances may be adapted for this purpose and -I show herein the following. Upon the front or upper side of each anode plate :formed a narrow chamber 26, therear Wall of said chamber being formed by the anode plate itself, and 'the front wall, 27 lbeing parallel to said anode plate. This chamber is, at suitable intervals ot time, supplied with mercury, and the pipe 32 is fed a small proportiom,

01": potassium cyanid to 2 oz. v

'mercuryruns from said chamber through or coating upon the silvered surface of thev plate. The mercury which tends to collect at the bottom of .each trough is drawn of by an overow pipe 29 running from the bottom of the trough and'thence to the sideof the apparatus and then upward to such a level, that when the mercury rises to a c er-A tain level in its trough it will overliow said overflow pipe 29i into a conduit 30 leading to a receptacle 31. From this receptacle it can be removed from time to time and retorted or redistributed among the several mercuryl chambers. By this means the levels of the ltroughsl are maintained constant notwithstanding the continual addition thereto of the mercury coming from the anode plates. Thus there is no loss whateverof mercury, andthere can be no 'flouring of the mercury, on account of the electric current continually passing therethrough.

The nature of the process Iis as follows:

The current of electricity passing through vthe aurifero'us material and mercurio chlorid in solution decomposes the mercurio chlorid. The chlorin immediately attacks the very thin film or coatin of rust or other oxid and removes said oxi ,'thus rendering the gold fit for amalgamation.

The words immediately thereafter in the claim refer not so much to the period of' so l time intervening between the preceding and subsequent steps recited therein as to the fact that between those steps there is no intermediate ste of the process or treatment of the material).

I claim The method of recovering gold which consists in mixing ore containing gold in a 'finely comminuted state'with an aqueous solution of a chlorin compound,immediately thereafter causing the mixture of solution and pulpfto flow in succession -freely in contact with al series of mercury cathodcs, passing currents of electricity through the {iowing mixture to said cathodes, the amount of chlorin compound and the magnitude of said currents being sufficiently great to liberate nascent chlorin in su cient quantities to reduce the gold to a condition in which it is readily amalgamated, and recovering the gold from the cathodes.

. JAMES H. ALLING. Witnesses:I

CHARLES A. yDINGMAN, J AMES G. FALLoN.

Images