Abstract: A method for obtaining silver and manganese metal from a silver-manganese ore includes the step of leaching the ore with acidified thiourea. More specifically, the method includes the step of leaching the ore with an acidic thiourea solution to form a leach liquor containing compounds of silver and manganese and an insoluble ore residue. The leach liquor is contacted with a quantity of activated carbon to adsorb the silver thiourea complexes on the carbon and to form an extract solution containing the manganese compounds. Next, the carbon which contains adsorbed silver thiourea complexes is contacted with an eluant to desorb the silver complexes from the carbon. The silver metal is recovered from the silver complexes obtained from desorbing the carbon. The manganese metal is recovered from the extract solution. The ore subjected to acidic thiourea leaching is selected from the group consisting of in situ ore, mined ore, comminuted ore, and ore concentrate.

Abstract: A method is provided for recovering gold and silver from precious metal bearing materials including ores, leaching residues, flue dust, electronic scrap, jewelry scrap, etc. In the method, the gold and silver are extracted from the precious metal bearing materials with a thiourea solution to form a thiourea leach, and the thiourea leach is contacted with carbon to adsorb the gold and silver and provide loaded carbon. The method is characterized by the step of contacting an alkaline solution of thiousulfate ion with the loaded carbon thereby desorbing the precious metals form the carbon. In one modification of the method, an additional step includes adding a salt to the aqueous thiousulfate solution. When needed, the method includes the step of protecting the thiousulfate ion from oxidizing agents. This is done by adding a reducing agent such as sodium sulfite to the thiousulfate solution.