METHOD OF DRY CONCENTRATION OF LEAN AURIFEROUS GRAVEL Russian patent published in 2007 - IPC B07B4/00 

FIELD: gold-mining industry; methods of dry concentration of auriferous gravel.

SUBSTANCE: proposed method employs the gravitational pneumatic system. Dry auriferous gravel is ground in centrifugal impact mills to size of 1.0^+0.05 mm and is dried to relative moisture content of 10-15%. Then ore is poured into bin having the slot at its end whose width is equal to 1.1 mm; this slot changes to taper chute inside which flat slotted nozzle is placed. This nozzle is used for forming the slotted injector. Compressed air is delivered to nozzle through receiver with the aid of compressor and reducer and ground ore is removed from bin and is sprayed into separator in form of flat jet. Then, flat jet is split into two flows by means of sailing effect and gravity force. Lower flow contains platinum metals and gold and upper flow contains particles whose sailing effect is twice as much as compared with particles of lower flow. Separation is performed with the aid of adjustable projection; then, concentrate of platinum metals is gathered together with gold in separator bin and is transferred with the aid of conveyer for final extraction of gold. Remaining components and compounds go to waste. Provision is made for sieves-screens which exclude clogging of slotted injector; besides that, injector surface is provided with mechanical vibrator working at frequency of 150-250 Hz and amplitude of up to 2 g. Adjustable swivel projection ensures selective separation of ore into two fractions; this projection is provided with control electric drive.

EFFECT: increased extraction of gold from lean auriferous gravel; all-season gold mining operations.

1 dwg