Abstract: The anodic and cathodic processes of pyrite in acid solution of sulfate and chloride have been studied.
The stable products of anodic processes are Fe~(3+), SO_4~(2-), as well as Fe~(2+) and S. The first stage of anodic reaction is:
FeS_3= Fe~(2+)+2S+2e~- (1)
followed by the oxidation of Fe~(2+) to Fe~(3+) and the production of SO_4~(2-). The relationship of overpotential (η) and the current density (Ⅰ) can be represented by the equation:
η=0.26+0.115lgI
the exchange current density is 0.005 A·m~(-2), and the standard rate constant is 2.58×10~(-8) ms~(-1).
The mechanism for the reaction (1) might be expressed as:...

Key words: Pyrite, Anodic and cathodic processes, Reaction mechanism