Abstract

The thermal decomposition of enargite (Cu3AsS4) in nitrogen was investigated by thermogravimetric analysis in the temperature range 575-700°C. The decomposition proceeds in two consecutive stages through the formation of tenantite (Cu12As4S13) as an intermediate compound. The decomposition of enargite and the subsequent decomposition of tenantite follows first order kinetics. The activation energies were 125 and 236 kJ/mol for the first and second stages, respectively. The final product of decomposition was a mixture of chalcocite and non-stoichiometric sulfides (Cu1.8S, Cu1.96S).