US1627181A - Amaigamator - Google Patents

Description

N. S. KEITH AMALGAMATOR May 3, 1927.

Filed April 21. 1924 3 Sh'eets-Sheat l {N VEN TOR.

l LPWVII.

1 L @L 1 E B E1 K Fig I.

WITNESSES.

- 1,627,! May 3, 1927. I N. s. KEITH 81 AMALGMATOH Fil'ed April 21. 1924 a Sheets-Sheet 2 WITNEsJES: I INVEN OR: asim. W 4/722? Patented May 3, 1927.

UNITED STATES 1,627,181 PATENT OFFICE.

NATHANIEL SHEPARD KEITH, F PHILADELPHIA, PENNSYLVANIA; CLAUDE L. ROTH, ADMINISTRATOR OF THE SAID NATHANIEL SHEPARD KEITH, DECEASED.

. AMALGAMATOR.

My invention relates to improvements in I added either during or after a milling, grind ing or concentration process.

Although amalgamators of a revolvable type have been used with some success in the treatment of pulverized ores, the con ditions under which most of them operate cause the mercury to be broken up and oxidized with the result that much mercury is lost, especially when pressure is used in addition to the force of gravity to pass the metalliferous pulp through a large mass of mercury. Furthermore, the precious metals in such ores are often in such fine particles or so flattened that they tend to float over the amalgamating surface iwithout coming in .contact with same or the metallic particles are so rusty or coated with impurities that they will not amalgamate' readily.

The object of my invention is to provide a machine and process whereby a large quantity of metalliferous pulp, to which mercury has been added, can be rapidly and cheaply brought into contact with an extensive amalgamating surface, by means of centrifugal force in the presence of nascent hydrogen, produced by electrolysis of he water, without using any pressure except 'centrifugal force and the force of gravity to pass the pulp over said surface so that the machine will have greater capacity and efficiency with less loss of mercury than other machines in common use.

I attain said object by applying said forces and an electrical current to such pulp containing mercury by meansof a novel apparatus, the chief features of which are a rotatable, vertical shaft carrying concentrically a disc having a boss around said shaft; a hollow, vertical cylinder held to i said disc by said boss and by compression of a cap holding the top of said cylinder rigidly to said shaft; a tube of lead. covering said cylinder but insulated therefrom and from said disc and cap: encircling said tube. an annular cup bolted to said disc but elevated. therefrom by adjustable washers; a reniov able vertical cylinder with an inner surface of copper and a serrated bottom resting in said cup and guyc'd to said disc and an insulated ring near the top of said shaft connected by conducting wire with said tube of lead and means for rotating said as a unit and supplying pulp containing mercury to the annular space between said cylinders and passing an electrical current to said ring and taking it up from said outer cylinder when said pulp is passing through the machine. The electrical current is used to produce nascent hydrogen at the amalgamating surface to preserve the brightness and receptive properties of the mercury. The apparatus is made operative by means of other devices combined with said fundamental features which I will now describe by explaining the construction and manner of using a simple form of machine embodying my invention and referring to the accompanying drawings illustrating the same in which like letters of reference are used to denote like parts of the apparatus, except as otherwise noted. 1 Figure 1 represents a vertical sectional view of the rotating arts of such machine and its bearings, wit out showing the lat eral supports or electrical connections.

Figure 2 is a view in which the lower parts of the cylinder and cup are relatively displaced, the former being shown in elevation, and the latter being shown in crosssection and illustrates the manner in which the bottom of said cylinder must be serrated to allow any excess of mercury or amalgam on the inner surface of said cylinderto be caught in said cup, which could not be as readily shown in Figure 1 without causing confusion in the lines thereof.

Figure 3 represents a plan view and Figure 4 a vertical view 'on an enlarged scale of the lower portions of the outer and inner cylinders and the annular cup and the disc by which they are supported respectively and the bolts and springs for keeping the outer cylinder in place while being rotated with the other parts aforesaid. Figure 4 also shows how the tube of lead surrounding the inner cylinder must be insulated therefrom and from said disc.

Figure 5 represents a top view of such machine when supported by a framework not shown in the previous figures without showing the clamp and wires needed for electrical corniection.

Figure ti represents a broken vertical section of the upper and lower portions of the machine when set in such a framework, not

parts including certain parts shown in Figure-4 or the bearin beneath the disc shown in Figure 1 whic bearing is to be supported by arms like the one shown beneath the pulley in Figure 6, bolted to a cross-bar extending to uprights at equal distances from the centre line of the shaft. This figure shows also the manner of making the electrical connections and introducing the pulp.

In all the figures, A represents a rotatable vertical shaft, preferably of steel, to be revolved in' bearings at the top, bottom and intermediate points marked with the letters B, B, B, B respectively as shown in Figure 1. The top bearing must be removab e and should be made with arms like a spider to be bolted to the upright supports of an outer frame shown in Figures 5 and 6 only. The intermediate bearings are not essential to the working ofthe machine except for the purpose of relieving strains on ot er parts and decreasing any tendency to oscillation. The shaft and all parts atfixed thereto may be turned at any desired speed by means of a pulley C fastened on said shaft and driven by a belt connected with a suitable source of power not shown. The bearing B at the bottom of the shaft must be set in a solid base from which vertical supports must be extended to projections of the top bearing B as shown inFigure 6. All bearings should be provided with bushings which are not always shown in the drawings.

D refers to the circular disc aforesaid, preferably made of metal, which must be fastened concentrically to the shaft A and is intended to support at some distance above it the concentric annular cup E through the medium of washers L, preferably of insulating material, through which are passed bolt-s K so as to leave spaces Z as outlets for the pulp to flow from the machine which outflow may be regulated by inserting or removing washers, but said outlets must not be increased to such an extent that the machine cannot be kept filled with pulp when rotated at a speed which would otherwise insure amalgamation.

F refers to a copper cylinder supported, concentrically in a vertical position by the annular cup E in which the bottom of said .cylinder rests at a sufficient distance from same therefrom, whicliinay be done more frequently than the cleaning up of the amalgamating surface of said cylinder without much interruption to operations.

said shaft must be threaded for some distance above said cap as shown in Figure 6.

P refers to a tube or covering of lead to be placed around the cylinder M except at the ends thereof, at such distance from said cylinder and said ends as will permit suflicient insulating material, such as melted asphalt, to be introduced between said lead and said cylinder and the metals adjacent to the end thereof to prevent any passage of electrical current from said lead as an anode to the outer cylinder F 18 a cathode in an electrical circuit except through the pulp as an electrolyte. The word, insulation is used in some of the figures to mark the space to be left'for that purpose.

R refers to a removable ring ortwo-piece clamp to be atlixed to the shaft A but insulated therefrom and to be connected with electric conducting wires with the lead tube or casing P'to make the latter an anode when a carbon electric brush connected with the positive pole of a source of electricity is caused to bear against the periphery of 'said ring or clamp while another such brush connected with the negative pole is caused to bear against the outside or upper edge of the outer cylinder F in such a manner that its inner surface of copper will act as a cathode in an electrolytic circuit, during the operation of the apparatus.

G denotes the springs for holding the outer cylinder F in place by means of stay bolts H on said cylinder and like bolts I on said disc D.

S refers to upright parts of the framework supporting the working parts of the apparatus and T to cross bars for holding the intermediate bearings B, B. firmly in position and U to angle irons for joining the upright supports to the'base of the machine.

X is a chute or launder for introducing the pulp in an obvious manner and Z refers to the spaces between the disc D and cup E divided by said bolted washers L through which itmust flow out of the machine.

To operate the machine it is first started rotating and then a stream of pulp is allowed to flow in the annular space between the two revolving cylinders F and M until said space is practically filled with pulp after which the pulp must not be allowed .to flow in faster than it is discharged from f-themachine through the outlet space Z,

which can be regulated as aforesaid to conform to the speed of rotation most suitable for amalgamation.

It is obvious that the revolving parts of the machine must be rotated at sufiicient speed to make the centrifugal force of their movement operate to bring the mercury and metals to be recovered from the pulp in contact with the copper amalgamating surface before the force of gravity takes such material through the machine and persons skilled in the art of amalgamating can readily determine what speed is necessary by observing the effect on said surface.

The amount of mercury added to the pulp should be kept as low as possible without impairing the eliiciency of the machine. A quantity equal to three times the weight of precious metal in the ore should be sufficient, that is to say for each ounce of gold to the ton of ore in the pulp three ounces of mercury should be added thereto in the launder X, if not introduced in a previous operation. As the pulp in which minute particles of precious metal are suspended or floating passes between said cylinders. each particle is impelled through the pulp by the centrifugal force of rotationtoward the copper amalgamating surface proportionately to its specific gravity with respect to other particles and the mercury being the most liquid and dense will most rapidly reach said sur face and having the property of forming an amalgam with copper will adhere thereto and absorb the particles of other metals impelled against such surface if they are capable of being amalgamated or wetted by the mercury. Particles which will not amalgamat-e will be displaced by the swirling action of the pulp and carried out of the machine. Mercury which remains liquid will tend to pass down said surface into the annular cup E while mercury accumulating precious metals will adhere to the amalgamating surface in a gradually hardenii'ig coat which must be removed by cleaning up from time to time as the aflinity of the mercury for precious metals is satisfied.

To clean up, first stop the flow of pulp and allow thepulp in the machine to run out. Then stop'the machine and remove the topmost bearing B by lifting itoff the shaft and detach the electrical brushes from the ring- R and cylinder F. Then free the cylinder F by releasing the springs (i and remove said cylinder. To save time in operating. a like cylinder may be put in its place and the said bearing and electrical connections replaced without waiting for the cylinder carrying amalgam to be cleaned in the manner well known to the art.

It will be'manii'est to those skilled in mechanics, after understanding my invention, that modifications and substitutions of equivalents may be made in the manner of forming and operating an apparatus of the kind Ihavc described without departing from the spirit or scope of my invention and that it is not to be limited to the particular apparatus described.

While the relative positions and dimensions of the various parts of an apparatus intended to apply my process may vary somewhat from those indicated by my drawings, I should say that in order to be effective there must be no change that will destroy the function for which I have designed any such parts and that the space between the two cylinders should not be less than one-tenth or more than three-tenths of the diameter of the outer cylinder and that the height of the cylinders should not be less than said diameter or exceed four times the same for obvious reasons.

I claim as my invention 1. In an amalgamating machine, the combination consisting of a rotatable, vertical shaft carrying concentrically a disc having a boss around said shaft; a hollow, vertical cylinder held to said disc by said boss and by compression of a cap holding the top of Cal said cylinder rigidly to said shaft; a tube of lead covering said cylinder, but insulated therefrom and from said disc and cap; en-

circling said tube, an annular cup bolted to said disc but elevated therefrom by adjustable washers; a removable vertical cylin= der with an inner surface of copper and a serrated bottom resting in said on and guyed to said disc and an'lnsulat-e ring near the top of said shaft connected by conducting wire with said tube of lead and means for rotating said parts as a unit and supplying pulp containing mercury to the annular space between said cylinders and passing an electrical current to said ring and taking it up fromsaid outer cylinder when said pulp is passing through the machine. I

2. In an amalgamating machine, the com: bination of a rotatable, vertical shaft a disc carried thereby, a verticall arranged inner cylinder carried by said of lead surrounding said cylinder, a com isc, atube its pression cap for holding said'inner cylinder ri idl to saidshaft, an outer, c lindrical cover of copper with a-serrated bottom edge which cover surrounds said cylinder, a memher having an annular recess secured upon said disc and within which recess said serrated edge is positioned, an insulated ring carried by said shaft, an electrical conductor between said covering of lead and said ring, means for supplying pulp containing mercury to' said outer cylinder, means for rotating said'shaft, and means for passing an electrical current to said ring and taking up said current from said outer cylinder.

3. In an amalgamating machine, the combination of a rotatable, vertical shaft, 2. disc carried thereby, a vertically arranged inner cylinder carried by said disc, a tube of lead surrounding said. cylinder, a compression cap for holding said inner cylinder rigidly to said shaft, an outer cylindrical cover of copper with a serrated bottom edge which cover surrounds said cylinder, means for resiliently securing the lower part of said outer cylinder to said disc, a member having an annular recess secured upon said disc and within which recess said serrated edge is positioned, an insulated ring carried by said shaft, an electrical conductor between carried thereby, a verticallyarranged inner cylinder carried'by said disc, a tube of lead surrounding said cylinder, a compression cap for holding said inner cylinder rigidly to said shaft, an outer cylindrical cover of copper with a serrated bottom edge which cover surrounds said cylinder, a member having an annular recess secured upon said disc and within which recess said serrated .edge is positioned, an insulated ring carried by said shaft, above said cylindrical cover and inner cylinder, an electrical conductor between said covering of lead and said ring, means for supplying pulp containing mercury to said outer cylinder, means for rotating said shaft, and means for passing an electrical current to said ring and taking ulxsaid current from said outer cylinder.

' In testimony whereof I afiix my signature.

NATHANIEL s. KEITH,

Images