Recovery of precious metal

摘要

An improved process for recovery for precious metals such as gold and silver from aqueous cyanide solutions by contact with certain guanidine reagents. The guanidine reagents not only extract the precious metal but may provide advantages in selectivity of gold over other metals, such as tetra- and pentahydrocarbon substituted non-resin guanidine reagents and tri- and tetra-hydrocarbon substituted resin guanidine reagents.