US1536375A - Apparatus for amalgamation - Google Patents

Description

May 5, 1925. 1,536,375

M.y K.' CODDING APPARATUS FOR AMALGAMATTON Filed April 1, 1920 2 Sheets-Sheet 1 t* L u; I i slaew pm) May 5, i925; 1,536,3"55

M. K. CODDING APPARATUS FOR AMALGAMATTON Filed April l, 1920 2 Sheets-Sheet 2 l; r..../// f v l 7] ,l `23 25 A 3ra-vauro@ MMI lwph' M? ma y sov Patented May i925.

NITE

rArN'r MAY IIRUMP CDlDING, OF SAN FRANCISCO', CALIFORNIA.

APPARATUS FOR AMALGAll/ITION.

Application led April 1,

To all whom t may concer/n:

Be it known that I, MAY IIRUMP CoDDrNo,

.a citizen of the United States, residing at San Francisco, in the county of San lFrancisco and State of California, have invented cert-ain new and useful Improvements in Apparatus for Amalgamation, ot which the following is a specification.

'Ihis invention relates to apparatus for amalgamation; `and it comprises as a new amalgamating apparatus, an amalgamating tank having a depressed or coned bottom adapted to hold a pool of mercury, one or more relatively vlong tubes lea-ding into the depression and off a height adapted to give a hydrostatic head of pulpfcd ore therein suliicient to overcome the resistance of mercury in the said depression, means tor feeding a pulp of ore and solution ill'to said tube and means for removing pulped ore at a point above the level of themercury; said means tor feeding pulped ore and removing lpulped ore -being advantageously so constructed as to promote a cyclic circulation to, through and away from' the .mercury bath; all as more. itully hereinafter set forth and as claimed.

agitation, however, comes the risk of flour-v ing the merchry that is, ot converting the mercury into minute globules which will be carriedotl with the barren portions of the It is' an object of the present invention to provide a type of amalgamator wherein intimate contact of the pulp and the mercury may he obtained, but without the danger of lossl by this flour-ing.

In most amalgamation processes gravital separation of the relativelyhea-vy metal particles trom the relatively light gangue particles is more or less relied upon; that is, the metal 4particles are expected to settle more readily to the bottom ot an agitated mixture of line ore and water than do the into by gravity, v the ieee. serian no. 370,434.

gangue particles. Ordinarily they do; but there are many ores in' which the separation in this manner is not as ready and completeas is desirable; there is a greater-or less proportion present in the lloured state which does not settle away from the gangue particles and come into contact with the mercury. Gravital separation of two classes of materials in a liquid is not wholly dependent upon the specific gravity of the two classes-it is also, in part, ldependent upon differences in size of the particles; a small particle,v whatever its specific gravity, always oliering a larger proportional surface to the liquid than a particle of greater size. Further, much diderence is made by 'the relations ot the surface ot the particlesl to the liquid-it frequently'happens that of two minerals ot'about the ysame. specific gravity and of the same size of particle, one settles through water much more rapidly than another.

In the present invention I have devised a type of' amalgamator of general applicability wherein I secure e'ective contact: of. the ore pulp and mercury by the expedient ot establishin and maintaining a column oit pulped ore with its base resting Ain the mercury and causing it to pass downward thereparticles heyond vthe baseof the column then risi-ng through the mercury. In so doing, enective contact is secured without'much agitation of the mercury and there is no ldanger of douring of the same.' In prde'r to produce a feed of the ore pulp through the mercury, I provide a tube YAot some height with its lower end helow the surface out the mercury bath and leed an ore pulp into this tube. It descends through the tube and is fed into the body of mercury by its vhydrostatic head. This method of feed is of course readily controllable to se-, cure a maximum eciency of contact between ore and mercury with a minimum oitn agitation ot the mercury. No violent agita-k tion, suchl as would our the mercury, is necessary in getting ood contact.

By an expedient can render this apparatus applicable to many ores containing native gold or native silver, 'which other.- wise are difficult to handle by amalgamation. .'Ihese ores are commonly of such character that on pulping with water there is no great tendency for the metal to separate gravitally from the gangue; the slowness of sepavration being, in some cases, due to the fine- 'common salt, (NaCl) and 1 or 2 faces. Whatever the reason, in this ore the value particles and the gangue particles do not separate well in pulps made with water. Instead of Water I may substitute as a pulping means a solution of an electrolyte..

All electrol tes exercise in water solution a profound e ect upon the capability of water for holding mineral particles in suspension; but the edect varies with each particular mineral particle. In a general' way, all neutral saline electrolytes exercise about the same effect upon any given mineral particle in water, although the specific effect of each is different. Basic electrolytes, ing the OH ion, upon suspended articles; but this eiiect, is usually 'quite' difiirent from that of neutral electrolyte. Chile saltpeter, or sodium nitrate, may be taken Vas typical of the former class of electrolytes and sodium or potassium carbonate as typical of the latter.

I find that many ores which will not sepav rate well with water will separate well in a solution of a neutral electrolyte, the electrolyte producing a differential 'action upon different particles. Similarly, they will give a better separation with basic electrolyte, although this is a diierent one from that of the neutral electrolyte. By using .both classes of electrolyte together a further differential is obtained.

In the present invention the stated facts are utilized. In using the type of amalgamator stated, instead of pulplnff the ore withwater alone, I may pulp it with a solution of an electrolyte; such electrolyte advantageously containing both classes of electrolyte. I may, for example, pulp the ore with a solution containing, say, 5 per cent of er cent of sodium carbonate' (soda ash). Ll3nt much better results are commonly secured by using Chile saltpeter as the neutral electrolyte and potassium carbonate as the basic electrolyte. Chile saltpeter superadds to its function as a dissolved electrolyte some other functions which apparently make it `much better adapted for the separation of native metals by amalgamation than some other neutral electrol es, such as salt. The difference is per aps due to its oxidizing powers; perhaps not. It may be noted in this connection, however, that since Chile saltpeter becomes basic on reduction and since most ores are reducing, in many embodiments -of my invention I simply .use a solution of Chile saltpeter, which will automatically develop more or less basic elec-A 4trolvte by its reduction.

T e same bath may be used over and over again upon pulped ore. In case the ore or those havalso have a profound eect contains acid impurities which tend to go into solution, as it often does, it may be desirable from time to time to treat thebath with a little milk of lime in order to regenerate its basicity and clean it of various dissolved matters forming insoluble lime salts. Water alone may be used with free milling ores and sands.

In the accompanying drawings I have shown several forms of apparatus within the purview of my invention. In the drawings- Fig. 1 is a View partly in section and partly in elevation and a more or less diagrammatic showing of an apparatus for carrying Vout my process;

Fig. 2 is a'vertical section through a modified form of an amalgamator;

Fig. 3 is a plan view of one form of prov form of nozzle;

Figa 6 is a front elevation of another form of stirrer or propeller;

Fig. 7 isa section along line 7--7 of Fig. 8; and

Fig. 8 is a vertical section partly in elevation of another form of amalgamating device.

Referring to the drawings, element 1 indicates a storage tank for Water or a chemical Vsolution to be' used in pulpi the ore. This tank .is in communication wlth the ore treating tank 2 by means of the valved pipe 3 and is. also in communication with the amalgamator 4 by means ofy a valved pipe 5. This pipe 5 is useful in sending solution or water `to the amalgamator from the tank l, the valve 6 being a 2-way valve for the purposeof directing the solution tothe tank 2 or the water or solution to the amalgamator 4. In addition water or chemicalesolution maybe added to the amalgamator through the valved line 7.

' The ore treatment tank 2 is provided with a 'shaft 8 carrying the stirrer 9,'the shaft being suitably journaled as at 10 and provided with a pulley 11 operated by belt 12 driven from a source of power not shown. The ore treatment tank 2 is further provided with a chute 13 by means of which the ore.

Valved pipe 18 also leads from the bottom of the ore treatment tank 2 to a pump 19 driven by shaft and pulley 2O and 21 respecllO The amalgamator 4, as shown in Fig. 1,'

comprises the main tank and the rotating hollow shaft 23. This shaft isl provided with a plurality of blades 24 which are adapted to lift the solution or the pulp which is fed down through the -hollow shaft/.23. The hollow shaft is provided at its end with a flared opening 25, the en d of which is seated below the level of the body of mercury 26 in the bottom 27 of the amalgamator. When the pulp is fed to the amalgamator either by means of the pump 19 or when it is fed down thetube 23 gravitally by means of the extension of pipe 22 in the tube 23, it passes into the body of mercury below the surface thereof, rises therethrough and is conducted outside the amalgamating device through chute 14 from whence it is delivered to the chute 13 and to the tank 2. The exi tension on pipe 22 delivers the solution toward the bottom, preferably not directly to the mercury and the solution rises in tube 23 until its head overcomesl the head of the mercury. The amalgamated metal may be withdrawn from the amalgamator through the valved pipe 29 and the Lvalues recovered in any known way.. The blades 24 on the hollow shaft' 23 are arranged to lift the pulp or solution in the amalgamator after it passes through the mercury and may be of @tti any desiredl form, such for instance as `that shown in Figs. 3, 4, l 6, 7 and 8. The propellcr or stirrers, however, are arranged in the `amalgamator in such a way that they affect only the solution or the pulp after its passage through the bath of mercury, the mercury in the conical end of the bottom of the amalgamator 4 being maintained as a relatively quiescent mass compared to the condition of the solution in the amalgamator. In order that the bath or body p may not be disturbed, and to prevent flouring, I have found it advantageous to` provide the bottom or lower end of the hollow shaft 23 with a. special form of nozzle such for in stance as' that shown in Figures 2 and 5. This nozzle may comprise a T 30 secured t0 the bottom of the delivery pipes. The pulp on solution flowing down the delivery pipe is delivered over the body of mercury to the tube 23, but not directly down upon the mercury. This arrangement provides for soft blow. I may also employ the device shown in Fig. 8 in ,which the lower ends of pipes 22 are provided with the closure 32, slots 33 being provided to direct the solution laterally.

I may use the lifting and stirring device of mercury shown in Figs. 2 and 3 which comprises a hollow shaft 23 provided with the wings 34 (preferably 4 in number). These wings are perforated' at 35 to lessen the resistance. The shaft 23 may be provided with the spiral blade 36 which may also be perforated as at 37. I may use the spiral stirring device shown in Fig. 4 which comprises the `shaft 23 and the spiral stirrer 38. In Fig. 6 I have shown another form of stirrer and lifting device.. The perforated paddles 39 (preferably 4 in number) may extend part way up the hollow shaft 23. The shaft may be provided with the spiral lifting blades 40 extending up the shaft a greater distance than the paddles 39. Y

Referring to Fig. 8 the amalgama-tor 4 may be provided with a relatively large tube or shaft' 23 carrying paddles 41 and the shaft may contain a plurality of delivery pipes 22 (5 shown). The blades 41 may be provided with thin stirrers 31 projecting into the body of mercury but these stirrers should not be arranged' to violently agitate the mercury. They should allow the mercury to remain relatively quiescent as compared to the solution being stirred by paddles 31. With free milling ores one passage through the amalgamator is usually sufficient.

The operation of the apparatus is obvious from the foregoing description'of the drawings. The pulp may be continuously circulated through the amalgamator 4 to the tank 2 to the pump 19 and back to the tube 23 in the device shown in Fig. 1 or in the devices shown in Figs. 2 and 8. When the metal amenable to amalgamation has been removed from the ore, the pulp may be sent to the table 16 and thence to the tank 17 for further treatment. The chemical solution such as sodium nitrate may be delivered to the tank 2 and the ore treated therein for some time and then the pulp `sent to the amalgamator by meansof the pump 19. During the operation the chemical solution from tank 1 may be fed either to the tank 2 by means of pipe 3 or to the tank 4 by means of pipe 5 as desired. The apparatus may be flushed or washed by means of water or the like which may be supplied from tank 1 after removal kof the solution therefrom and which may be sent from this tank 1 to the amalgamator by the pipe 5. Or the amalgamators nay be washed with Water through ipe P While it is desired to maintain the bath of mercur relatively quiescent as compared to the bo y of solution or pulp in the amalgamator, I find it desirable in some instances to stir the mercury slightly. This may be done by the provision of the stirrers 31 attached to the bottom of the paddles 41 shown in Fig. .8. However these stirrers should not agitate the mercury to any great extent and should not agitate it or churn itw to the extent'that the solution abovexthe mercury in the amalgamator is stirred.

`What claim is 1. Apparatus for treating ore comprising a mixing tank for pulping ore with aqueous liquids and amalgamator in connection with the tank, said amalgamator comprising a main receptacle, pulp feeding means near the bottom thereof, means for maintaining a column of pulped material in said main receptacle and surrounding said pulp feeding means, a bath of mercury covering the lower end of the said column maintaining means, and means for removing pulp immediately after its passage-through the mercury.

2. Apparatus for treating ore, comprising a mixing tank for pulping .ore with aqueous liquids, and an amalgamator in connection' with the tank, said amalgamator comprising a main tank, pulp feeding means near the bottom thereof, means for maintaining a column of pulped material in said main receptacle and surrounding said pulp feeding means, a bath of mercury covering the lower end of the said columnmaintaining means, and means attached to said column maintaining means for removing pulp immediate-v of pulped material, said means terminating below the surface of the mercury, and means inside the column maintaining means and terminating near the bottom thereof for delivering pulped ore in the column maintaining means.

4. An amalgamator comprising a main tank, a basin at the bottom thereof for holding mercury, mercury in said basin, means in the main tank for maintaining a column of pulped material, said means terminating below the surface of the mercury, and means inside the column maintaining means and terminating near the bottom thereof but above the surface ofthe mercury for delivering pulped ore in the column maintaining means. v

5. An amalgamator comprising a main tank, a basin at the bottom thereof for holding mercury, mercury in vsaid basin, means for maintaining a column of pulped material `above said mercury, such means terminating below the'surface of the mercury, and means inside said column maintaining means for feeding pulped-.material thereto, said pulped ore feeding means having a delivery end arranged to deliver the pulp laterally of the column to prevent substantial disturbance of the mercury.

In testimony whereof, I aix my signature hereto.

MAY KRUMP CODDNG.

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