The Effect of Clay Minerals on Fayalite Slag Structure and Refractory Brick Wear during Copper Smelting

Abstract

Metallic copper production via the pyrometallurgical route is hindered due to the increased presence of gangue in the clay minerals in copper sulfide concentrates and its unpredictable effect on this operation. In this study, the relationship between smelting copper slag composition, including the clay components and the refractory brick wear, was investigated in experimental laboratory tests. Synthetic fayalite slags doped with 2, 5, or 8 wt% high-purity kaolinite or montmorillonite were introduced into magnesia chromite refractory crucibles and melted in an electrical furnace under the controlled partial pressure of oxygen (10−8 atm) for 12 h at temperatures of 1250 and 1300 °C. After the experimental time, the crucibles were quenched in water, and the obtained samples were analyzed using the XRD, SEM, and ICP techniques. According to the results, at 1300 °C the presence of montmorillonite in the fayalite-based slag promoted infiltration through the refractory brick and increased the dissolution of the magnesia component from the hot face. In the case of the kaolinite, the infiltration was even higher, but the magnesia dissolution was delayed.

Keywords

• refractory wear
• magnesia chromite refractory
• clay minerals
• copper slag
• copper pyrometallurgical production