Effect of MgO on physicochemical property and phase transformation in copper slag

The cleaning of copper slag is an important way to realize the sustainable development of the copper metallurgy industry. MgO is a commonly used additive in the cleaning process and has an important impact on the physicochemical properties of copper slag. However, there are few studies on the mechanism of the phase transformation of the ISASMELT copper slag with different additive amounts of MgO. In this study, the mechanism of the phase transformation of copper slag with different additive amounts of MgO and the effect of MgO on the mass action concentration of slag component, physicochemical properties of copper slag and copper loss were elucidated. The results showed that when the MgO was added to copper slag, high melting point hortonolite was formed in the slag. When the additive amount of MgO was more than 4%, high melting point pleonaste was formed. With increasing MgO additive amount, the slag viscosity increased, and the silicate structure tended to be complex. Adding MgO to slag was not conducive to the recovery of matte from copper slag. The results provide a theoretical basis for selecting the most reasonable slag type in the cleaning process of ISASMELT copper slag and selecting the reasonable raw material in the ISASMELT process of copper concentrate.