Direct-to-blister Smelting of High-Alumina Chalcocite Based on Al2O3-CaO-SiO2 Slag System

Reasonable slag type is the key to the smooth progress of smelting. In this study, the direct-to-blister smelting experiment was carried out on a laboratory scale using high-alumina chalcocite as raw material and using Al2O3-CaO-SiO2 slag system. The changes of the copper recovery with the ratio of CaO/SiO2 and the content of Al2O3 were studied. The phase composition, structural characteristics and copper loss of the slag were analyzed by XRD, SEM-EDS, FTIR and Raman spectroscopy. The results show that when the CaO/SiO2 is 1 and the Al2O3 content is 20%, the copper recovery reaches the maximum, which is 91.69%. The effects of CaO/SiO2 ratio and Al2O3 content on slag structure and viscosity at 1340celcius were analyzed in detail. The precipitation of high melting point phases and the change in aluminosilicate structure are the main reasons for the influence of slag viscosity.