Show ZINC DUST precipitation OF COPPER FROM CYANIDE SOLUTION if zinc dust be used to precipitate copper gold old and silver from cyanide solution where the copper content accounts for excessive cyanide loss during the leaching period the reuse of the cyanide solution will soon result in it becoming fouled with zinc As the percentage of zinc in the cyanide solution increases the reuse of these solutions results in corresponding decrease in the extraction of the metals particularly silver studies conducted by the rare and precious metals experiment station of the united states bureau of mines reno nevada show that decreased extraction is noticeable when the solution contains near per cent zinc when it contains per cent zinc the cyanide extraction of silver drops from 90 per cent to 75 per cent this explains why zinc precipitation can not be satisfactorily used in cyanide practice when there is considerable soluble copper in the ore |