Phase equilibria in the CuO0.5-SbO1.5-SiO2 system

Phase equilibria information are significant for optimizing recovery of Sb in industrial Cu production. An integrated experimental and thermodynamic modeling investigation of the phase equilibria in the CuO0.5-SbO1.5-SiO2 system has been undertaken to characterize the distribution of Sb between high-Cu slags and matte/metal phase in the Cu processing reactors. New experimental phase equilibria data at 600-1500 degrees C were obtained for this system using high-temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules or Cu foils, a rapid quenching technique, and electron probe x-ray microanalysis of the equilibrated phase compositions. Phase equilibria and liquidus isotherms in the cuprite Cu2O, quartz/tridymite/cristobalite SiO2, valentinite Sb2O3, and cervantite Sb2O4 primary phase fields were measured, and the extent of the high-SiO2 2-liquid immiscibility gap in equilibrium with cristobalite was determined. Experimental results were used to fix thermodynamic parameters in the CuO0.5-SbO1.5 binary and the CuO0.5-SbO1.5-SiO2 ternary systems. Moreover, the solubility of Sb in the metal phase (predominantly Cu) was predicted reasonably through the thermodynamic database. The information obtained in this study is important for recycling critical metal Sb with increasing demand in the ceramic and glass applications as well as low-carbon energy production.