US2004939A - Gold recovering device and method - Google Patents

Description

June 18, 1935. J. B. GIRAND GOLD RECOVERING DEVICE AND METHOD Filed Feb. 9; 1952 2 Sheets-Sheet 1 INVENTOR Umes B. Girm1d, BY W Va ATTORNEY WITNESS 501/ June 18, 1935. J. B. GIRAND GOLD RECOVERING DEVICE AND METHOD Filed Feb. 9, 1932 2 Sheets-Sheet 2 INVENTOR @mes .3. GI:

ATTORN EY Patented June 18, 1935 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to a device and method for recovering gold from other heavy materials such as sand, refuse or gold-bearing ores.

An object of the invention is the provision of a device which utilizes the centrifugal force developed within a rotating drum to separate the heavy materials from the lighter materials.

Another object of the invention is the provision of a device which utilizes the centrifugal force developed within a rotating drum for not only separating the heavy materials from the light -materials, but which provides a cushioning bed at the greatest diameter of the rotating drum to re ceive the heavy particles while permitting the lighter particles to pass beyond the cushioning bed.

A further object of the invention is the provision of a device utilizing the centrifugal force developed within a rotating drum formed of two truncated cones having their larger ends connected together and providing a pocket to receive and retain a cushioning material for collecting the heavier materials which are thrown out by centrifugal force from the lighter materials, a spray being included in the drum adjacent the entrance for supplying water streams to loosen, liquefy, agitate and disintegrate the materials entering the drum, the water being supplied in suflicient quantities to carry off the lighter materials from the drum. I

This invention will be best understood from a consideration of the following detailed description, in view of the accompanying drawings forming a part of the specification; nevertheless it is to be understood that the invention is not con fined to the disclosure, being susceptible of such changes and modifications which shall define no Figure 5 is a transverse vertical section taken along the line 5-5 of Figure 1,

Figure 6 is a transverse vertical section taken along the line66 of Figure'l,

Figure 'I is a fragmentary vertical section of 5 a modified form of the drum shown in Figure 1.

(on. ass-.21)

Referring more particularly to the drawings,

I0 designates a driven shaft to which is secured spaced flanged wheels II. The flanges of these wheels are at the inner face thereof and are adapted to engage rings I2 secured to the outer Y 5 face of a revolving drum, generally designated by the numeral I3. A second pair of wheels I are mounted upon an axle l5 carried by bearings I6. The axle in adjacent the front wheel II is mounted on bearings I1 and this bearing, to- 10 gether with the bearings I6, adjacent the front wheel I4 is secured to an angle iron beam l8 which is supported upon standards IS. The rear ends of the shaft I0 and axle I5 are supported by similar bearings 20 secured to an angle iron 15 beam 2|. Thus it will be seen that the four flanged wheels II and it support the drum I3 while the driven wheels ll operate to revolve said drum. I

A chain 22 trained over a sprocket 23 secured go to the shaft Ill drives said sprocket and shaft thro'ugh'a sprocket 24 and a shaft 25 to which the sprocket-24 is secured. A hand crank 26 is shown connected to the shaft 25 to provide means for rotating the shaft. It will be appreciated, 5 however, that the shaft 25 may be connected in any approved manner with a power plant. Braces 21 support the shaft 25 by the usual bearings.

The drum I3 is formed of two truncated cones 30 30 and 3| which have their ends of greater diam eter connected together at 32, thereby providing an annular pocket which is V-shaped in cross section and which is adapted to receive a cushioning element 33 as will be presently explained. 35 It will be noted that the entrance 34 is-of less diameter than the'discharge opening 35 and is located at a higher horizontal plane than the lower end of the discharge opening 35.

A chute 40 is in communication at its upper 40 end with a hopper 4| which is adapted to receive the gold-bearing sand or ore as indicated at 42. A valve, generally designated by the numeral 43, is included within the chute 40 and is controlled by a wheel 44 for regulating the quantity of ore 45 or sand passing through the chute 40. The inner lower end 45 of the chute projects within the reduced entrance '34 of the drum I3 so that the materials may be fed into the drum at all times during rotation of the drum.

A pipe 46 is connected with a water supply and a valve (not shown) will control the flow of the water to the perforated discharge pipe 41 which is located horizontally within the revolving drum I3 and at the reduced portion of the outer end 65 40 fecting a much faster separation than when the of the truncated section of the drum. The perforated discharge pipe 41 is adapted to spray a definite quantity of water onto the incoming gold-bearing sands or ore in order to saturate the ore with suflicient water to loosen the same so that it will be churned as it enters the drum and suflicient water will be supplied to maintain a stream of water through the drum to carry off the lighter materials after the heavier metallic materials have been received by the annular cushion.

A travelling carrier in the form of a belt is shown at 50 and is trained over a, cylinder 5| which acts as an idler for supporting the belt 50 just beneath the discharge opening 35. It will be appreciated that a driving drum (not shown) is employed for operating the travelling carrier 50.

In Figure 7 a modified form of the drum l3 shown in Fig. 6 is disclosed herewith. This type of drum is formed of the truncated sections 52 and 53 and is similar in all respects to the drum l3 except that the portion 54 is somewhat fiattened to form substantially a ring 55 instead of the sharp pointed member 32, as shown in Fig. 1.

.great deal of gold is found in the sands or ore.

The operation of my device is as follows: Any type of means may be employed for driving the shaft 25 and likewise .rotating the drum l3. It is essential, however, that the speed of the drum be under accurate control since the successful operation of the device depends upon the critical speed of rotation of the drum.

The separation of this machine is effected by utilizing the centrifugal force within the drum to increase the diflerence in weights between the heavy material and the light material, thus efforce of gravity alone is used. An important feature in this method of separation is effected by the centrifugal force.

The drumhas its longitudinal axis located in a horizontal plane so that when a particle is rotating about said axis and on a fixed radius there is a critical speed above which the centrifugal force is greater than the force of gravity and the particles will cling to the drum. Below this critical. speed the particle will be controlled in its movement by gravity. The critical speed and radius may be deduced from the formula 1 inn/E when n= the speed in revolutions per second.

R= the critical radius in feet and it will be noted that R in Figs. 3 to 5, inclusive, which represents the various radii discloses the critical radii of the various sections.

It will be obvious from the above that the cushioning material is subjected to rapid altemations of forces keeping the cushions soft and preventing packing. These alternating forces are the centrifugal force which tends to throw the particles away from the center and the force of gravity which tends to pull all of the particles downwardly. As has been explained, the net force on particles which are moving through the upper portions of the circular layer is less than the net force on the lower portions where both cento act on the particles in one direction.

During the operation of the-machine the drum is revolved at the crifical speed. Sand and other material is admitted to the drum until the periphery or V-shaped section, indicated at a, in Figure 1, is filled to the critical radius R, thus forming the controlling cushion. when it is filled exactly to the critical radius all the mate rial beyond the critical radius will cling to the V-shaped section 53 but all material at the radius R will be in unstable equilibrium; that is, just on the border line between clinging and falling. Since water is being admitted through the perforated pipe" the controlling surface is very soft and spongy so that when a particle of material heavier than sand forming the controlling cushion touches the surface it will readily and rapidly penetrate into the controlling cushion. The water which is admitted not only aids in the' rapidity in the penetration of the heavier particles but maintains the contents of the cushion as fluid as far as possible, thus preventing undue packing of the cushion.

After the controlling cushion is in place and ready for operation, the gold-bearing sand or other material will be continuously fed from the hopper ll through a chute 4. and controlled by the valve 43. As this material passes into the drum it is agitated, washed and broken up by the jets of water adjacent the entrance 34. Since the radius of that portion of the drum which is adjacent the entrance is less than the critical radius the material will be churned and agitated after it enters the wider portions of the drum. The specific gravity of the material which is fed into the drum is substantially the same as that of the collecting cushion. None of this material can force its way into the controlling cushion. However, when particles of gold come in contact with this cushion it penetrates the spongy mass and as the gold particles pass beyond the surface of the controlling cushion the radius of its base is increased and thereby centrifugal force is likewise increased, thereby overcoming the gravitational pull. The gold will thus cling and remain. within the collecting cushion.

The discharge end of the drum has a greater diameter than the inlet and the material rapidly works its way to the outlet where it is discharged after having been divested of all its metallic contents. This operation is continuous and the heavier material continues to collect until all the absorbing cushion is displaced or the machine has been emptied.

It has been found in practice that it is advantageous to first build up a controlling cushion of some material heavier than the ore to be fed but much lighter than the gold. A black iron" sand with a specific gravity of approximately 7 has been successfully used. This cushion is sufficiently heavy to prevent the larger rocks or boulders becoming lodged therein. The larger gravel and boulders which may be introduced pass rapidly through and are readily divested of the metallic contents.

The stony or earthy substance which is associated with the metallic ore is designated as gangue and this gangue may be in the form of sand, pebbles, and other earthy matter as is well known. 5

Where the gold or other materials do not occur in large quantities, the machine may be operated continuously for a day or more after which all the materials are removed from the interior.

These concentrates may be separated by a smaller' machine in any well known manner.

Where the quantity of the heavier materials is-large a drum of the type shown in Fig. 7 is employed so that the heavy materials will be continuously discharged from the openings 56. Any form of means may embrace the exterior of the .band or ring 55 to receive the particles of gold as they are discharged.

It will be obvious that where a critical. speed is maintained so that the centrifugal force will retain the gangue in a cushion as indicated at 33 in Fig. 1 and as is also shown in Figs. 3 to 5, inclusive, the gangue will be subjected to the force of gravity at all times but when the cushion reaches the uppermost limit in its annular path in a vertical plane, the force of gravity will oppose the centrifugal force and will tend to remove the cushion at these points. Thus as the cushion passes its highest point of travel the particles will be loosened due to the opposing forces and the cushion will be less compact at this time as opposed to the bottom portion of the path of the cushion where gravity and centrifugal force combine to move the particles downwardly. Therefore, the particles of gold under the influence of centrifugal force will penetrate the cushion more readily during the upper portion of the travel of the cushion.

It will be appreciated that no extraneous metal or matter is required in this method of concentrating the metallic particles from gangue particles since the cushion in which the metallic particles are embedded is formed from the gangue particles which enter with the metallic particles. It will be further appreciated that as the metallic particles enter the cushion these metallic particles will displace. gangue particles continuously.

I claim:

l. A device for recovering metallic particles from materials which include gangue comprising a drum. rotating on a horizontal axis having an intermediate portion of greater diameter than the remaining portions and forming an annular pocket, cushioning material consisting of gangue and free metal and being retained in the annular pocket, the cushioning material being subjected to rapid alternations of forces due to the change in direction of the centrifugal force on the individual particles thus keeping the cushion soft and preventing packing, said cushioning material being in a plane which is at an angle to the horizontal, means for feeding metal bearing material to the drum, means for revolving the drum at a critical speed so that the cushioning material will be retained in the pocket'and receive and retain the metallic particles in the cushion, and means for supplying a liquid to the materials being fed to the drum.

2. A method of concentrating metallic particles from gangue particles which are lighter than said metallic particles, which consists in feeding said particles through a zone in which said particles are caused to move in spiral paths, said paths initially increasing in diameter from the inlet end of said zone and then decreasing in diameter towards the outlet end of said zone, so that said particles are subjected to a varying centrifugal force in said zone, said centrifugal force being sufficient only to maintain a layer of gangue in the widest portion of said zone, said centrifugal force being insuflicient to maintain a layer of said gangue adjacent said inlet end and said outlet end, continuously feeding gangue through the zone and causing the particles of the gangue to said metallic particles, which consists in feeding.

said particles through a zone in which said particles are caused to move in spiral paths, said paths initially increasing in diameter from the inlet end of said zone and then decreasing in diameter towards the outlet end of said zone, so that said particles are subjected to a varying centrifugal force in said zone, said centrifugal force being sufficient only to maintain a layer of gangue in the widest portion of said zone, said centrifugal force being insuflicient to maintain a layer of said gangue adjacent said inlet end and said outlet end, continuously feeding gangue through the zone and causing the particles of the gangue to move through the spiral path and over the layer of gangue, while causing the metallic particles in free metallic condition to penetrate said layer, the centrifugal force being suflicient to maintain said metallic particles in said gangue layer, while moistening said gangue particles so as to facilitate the penetration of said gangue layer by said metallic particles, said gangue layer being maintained in the form of a coherent mass by said centrifugal force.

4. A method of concentrating metallic particles from gangue which comprises feeding the gangue and metallic particles into a zone and causing all of the particles to move through a spiral path while gradually increasing the diameters of the path to a maximum, forming at the path of maximum diameter a layer of gangue where the metallic particles will be collected, said layer being in a plane which is at an angle to the horizontal, revolving the annular layer at a critical speed to maintain a predetermined thickness of the layer while subjecting the layer periodically to the opposing force of gravity so that the inner portions of the layer will be'loose to permit the metallic particles to penetrate the layer, continuously feeding the gangue containing metallic particles to the zone and moving the gangue and particles through the same spiral path so that the metallic particles when reaching the layer will penetrate the same'while the lighter gangue particles will pass over the layer and be discharged from the zone.

5. A method of concentrating mineral particles from gangue particles which are lighter than said mineral particles, which consists in feeding the particles through a zone in which said particles are caused to move in paths, said paths being in planes at an angle to the horizontal and initially increasing in diameter from the inlet end of said zone to a part in said zone where sufficient particles are interrupted in their progress to form a layer of gangue particles which includes free mineral particles and where centrifugal force will be sufficient to maintain said layer substantially intact against the force of gravity, feeding additional gangue materials containing mineral particles to the paths and causing said materials to pass over the layer of gangue .while causing the mineral particles in free condition to penetrate said layer. I

6. A method of concentrating mineral particles from an aggregate, said method comprising feeding the aggregate and its suspended mineral particles into a zone of separation in which said the horizontal, interrupting the paths of enough of the aggregate by an unyielding surface which defines said zone to accumulate a substantially internally cylindrically-surfaced annularcushion relatively sparse in recoverable mineral particles, said cushion when passing through the highest portion of its path being less compact than when passing through the lowermost portion of its path, flowing a stream of additional aggregate also with suspended mineral particles across the cylindrical surface of said cushion, and supplying moisture to said stream at its point of en.- trance into said zone first to agitate and liquefy the stream so as to facilitate the gravitation of its mineral particles away from their path of progress across the cushion, second to liquefy the cushionso that when the gravitated particles touch the surface thereof they are disassociated in free condition from the stream and are caused to 'centrifugally penetrate the cushion.

JALIES B. GIRAND.

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