SO_2/O_2 as an oxidant in hydrometallurgy

摘要

Oxygen mixed with SO_2 can function as a powerful oxidant in acid solution. This paper summarises basic studies on the mechanism of SO_2/O_2 oxidation, the kinetics of oxidation in acidic media, and potential applications in hydrometallurgy. The SO_2/O_2 system readily oxidises Fe(II) to Fe(III) and provides a simple method of regenerating Fe(III) for leaching minerals like Cu_2S or U_3O_8. It also oxidises As(III), which; in the presence of iron(III) enables a stable ferric arsenate compound to be precipitated.. A method for the leaching and removal of arsenic from smelter fumes is proposed. Oxidation of Mn(II) to Mn(III)/Mn(IV) oxides by SO_2/O_2 allows manganese impurity to be removed from leach liquors and electrolytes.