A method for recovering precious metals such as gold and silver from aqueous solution as solid is described The method includes mixing an aqueous solution (e.g, thiosulfate or thiocyanate lixiviant) containing precious metals with ferrous ions in the presence of an effective amount of hydroxide ions....http://www.google.es/patents/US7972413?utm_source=gb-gplus-sharePatente US7972413 - Precious metal recovery from solution
