Oxygen mixed with SO2 can function as a powerful oxidant in acid solution.
This paper summarises basic studies on the mechanism of SO2/O-2 oxidation,
the kinetics of oxidation in acidic media, and potential applications in hy
drometallurgy. The SO2/O-2 system readily oxidises Fe(II) to Fe(III) and pr
ovides a simple method of regenerating Fe(III) for leaching minerals like C
u2S or U3O8. It also oxidises As(III), which in the presence of iron(III) e
nables a stable ferric arsenate compound to be precipitated.. A method for
the leaching and removal of arsenic front smelter fumes is proposed. Oxidat
ion of Mn(II) to Mn(III)/Mn(IV) oxides by SO2/O-2 allows manganese impurity
to be removed from leach liquors and electrolytes. (C) 2000 Elsevier Scien
ce Ltd. All rights reserved.