Review of recent progress on dissolution of precious metals and speciation of their complexes in aqueous solutions

Abstract

Highly effective refining of precious metals requires detailed knowledge of the chemical properties of their complexes in leaching solutions. Speciation studies on precious metal ions in solution have been performed for about a century. Early studies have mainly provided stability constants between precious metal ions and their ligands. Recently, improvement of analytical technologies has facilitated advanced speciation including determination of the information on detailed structure for the metal complexes. This review presents the dominant species of precious metal complexes in cyanogen, hydrochloric acid, and nitric acid solutions, and their leaching systems. In addition, conventional and current speciation methods are discussed.