Slag Reduction Kinetics of Copper Slags from Primary Copper Production

Abstract

In the classical pyrometallurgical route for copper production from sulphide concentrates, the treatment of slags aims to recover copper through the coalescence of copper metal and copper sulphide particles. To assist with this settling process, a reductant is added to the slag to reduce the spinel precipitated phases (magnetite) in order to diminish the viscosity of the slag. While the impact on viscosity is typically the majority of reports in the literature, there is also the potential to reduce Cu₂O and Cu₂S dissolved in the slag. This can result in improved settling and increased recovery of copper.

An experimental study on the reduction kinetic of industrial slags was done to evaluate the intrinsic rate of reduction of those types of copper slags by methane. The results are compared with the available literature on the rate of reduction for these types of reactions, showing that copper reduction is one the order of magnitude higher than the reduction of FeO, which is the key step of the smelting reduction processes developed in the ’80s.