Kinetics of As, Sb, Bi and Pb volatilization from industrial copper matte during Ar+O2 bubbling

Abstract

A kinetic study on minor elements removal during copper matte oxidation was designed under the presumptions of low FeO activity and of no fayalite slag formation. Copper matte with a mass fraction of Cu of 59 pct was mixed by Ar gas blowing during preheating. The matte was oxidized at 1523 and 1673 K by bubbling Ar+O2 gas through a submerged nozzle. The effects of melt temperature and input oxygen content on the oxidation rate of matte and the volatilization rate of minor elements in copper matte are discussed. The competition reaction composed of the oxygen dissolution into matte and SO2 gas evolution rate results in the preferential oxidation of FeS in copper matte. The desulfurization rate of matte and the volatilization of minor elements in copper matte were primarily controlled by the mass-transfer rate through the gas film boundary layer around rising gas bubbles. The As, Pb, and Bi were significantly removed during Ar gas blowing with the volatilization rates of Bi and Pb markedly increasing with the melt temperature. However, the dependences of the volatilization rates on the input oxygen partial pressure were affected in a complicated way by the effects of the melt temperature and the reduced amount of exhaust gas.