Abstract:

The properties of the coordination compoands of Au(Ⅲ), Au(Ⅰ) and Ag(Ⅰ) with mercapto-acetanil (MAA or HL) are reported.The AuL₃ type of the compounds is synthesized for the first time and characterized by elemental analysis, UV, IR and TG-DTA. The ligand (MAA) selectively chelates Au(Ⅲ) from acidic solution or aqua regia containing ions such as Ca, Mg, Cd, Mn, Co, Ni, Cu, Zn and Fe. The formed AuL₃. then converts into Au(Ⅰ)L in absolute ethyl alcohol. The gold and silver were recovered through high temperature decomposition of the AuL₃ and AgL, respectively. The recovery ratio for gold is over 97%, for silver over 98%. The purity of the obtained gold is 99.89～99.98%. The cost of the method is much lower than that of using zinc pyridinethione as a chelating agent.

Key words: Au(Ⅲ), Ag(Ⅰ), mercapto-acetanil, coordination compound, recouery