Abstract: A precious metal recovery system utilizing an amalgamation process which results in substantially complete recovery both of the precious metal sought and of the mercury utilized in the process. Mercury has undesirable health and environmental characteristics and the system of the invention assures its substantial containment. In the operation of the system, ore is classified and sorted out into a plurality of bins or holds containing ore having a substantially uniform particle size. The ore is then delivered, bin by bin, beginning with the smallest particle size, to apparatus which assures substantially complete amalgamation of all of the precious metal present in the ore. Thereafter, a resulting slurry of water and tails is first removed from the amalgamation apparatus and any residual mercury removed before its return to the environment.

Abstract: A thermal gravity classifier in which various nonferrous scrap metals are classified and separated, using a single tank containing two layers of molten media. Shredded nonferrous scrap containing metal constituents such as aluminum, zinc, lead, and copper or the like are introduced to the top of the tank containing an upper layer of molten zinc, floating on a lower layer of molten lead. Metals such as aluminum, having a specific gravity less than zinc, by a screw conveyor approximately parallel with the top surface. Heavier metals and alloys such as copper or the like, having a melting point above the temperature within the tank, fall through the zinc layer and are conveyed from the tank by a separate screw conveyor extending up a diagonal wall of the tank. Metals such as lead and zinc, having a melting point lower than the temperature maintained within the tank, melt and gravitate to the appropriate molten layer in the tank.

Abstract: A drum is supported for rotation between two shafts having gears thereon engaging a ring gear around the outer periphery of the drum. A crushing and milling cylinder is journalled for rotation upon a vertically adjustable shaft extending freely through the entrance and exit apertures in the side plates of the drum and this shaft is supported within stationary bearings one upon each side of the drum. The sludge comprising finely crushed rock and water is discharged through the exit in one side wall and into a hopper where it is conveyed by a conveyor system over and through a bed of mercury which extracts the gold in the form of an amalgam. The sludge is then discharged from the other side of the mercury bed.