CHARACTERIZATION OF GOLD AND COPPER COMPLEXES IN CYANIDE-GLYCINE SYSTEM BY UV-VIS SPECTROSCOPY

Abstract

In the process of gold ores leaching by glycine and cyanide, the interactions between glycine and cyanide with metals are not well understood and there is little research in this area. The characterization of gold and copper complexes in the cyanide-glycine system by UV-Vis spectroscopy method is studied. Job’s method of continuous variation was applied to ascertain the stoichiometry composition of the complexes. The results showed that in the glycine-gold-copper system, although the stability constant of the gold-glycine complex is higher, the dominant species formed is the copper-glycine complex. In the cyanide-gold-copper system, gold forms complexes with cyanide and to a lesser extent glycine, which agrees with their stability constants. If the cyanide and glycine ligands are added to a gold solution, the dominant species in the system is the gold-cyanide complex. In the cyanide-glycine-copper system, the dominant species in the system is the copper-glycine complex. When cyanide and glycine ligands are added to a gold-copper solution, the dominant species in the system are the copper-glycine and the gold-cyanide complexes.