A PROCESS FOR RECOVERING PRECIOUS METALS FROM SECONDARY RESOURCES

Suggested is a method for recovering precious metals from secondary resources comprising or consisting of the following steps: (a) providing a source of solid waste material comprising precious metals in an amount of at least 0.0001% b.w.; (b) bringing said waste material into contact with heterotrophic micro-organisms capable of producing and releasing hydrocyanic acid; (c) adding a solvent or an aqueous nutrient solution capable of serving as a nutrient source for said micro-organisms to the mixture; (d) depleting said waste materials from the precious metals contained therein by complexation of the metals with said hydrocyanic acid released by said micro-organisms; (e) separating the depleted solid waste material from the liquid containing the metal-cyano complexes; (f) recovering the precious metals from their cyano-complexes in known manner.