Solvents and methods for leaching precious metals

Abstract

A recyclable, non-toxic solvent media and methods for precious metal leaching and extraction, in particular platinum group metals (PGMs), are described. The solvent media comprises 3-methoxy-3-methyl-1-butanol (MMB), an oxidizing agent such as lithium bromate, and a halogen salt such as lithium bromide. A precious metal leaching process comprises preparing the solvent media, adding precious metal-containing substance to the solvent media and agitation to leach the precious metal from the substance into the solvent. Agitation may be performed for several hours to days at relatively low temperature. After leaching, filtration is performed to separate the solvent-soluble precious metals from insoluble residues. The method may further comprise refinement of the precious metal and purification of the solvent. Purified solvent may be recycled/reused in solvent media for leaching and extraction of precious metals.

Dependencies are inferred from the claim text.