REACTIVITY OF MECHANICALLY ACTIVATED PYRITE

We have studied the decomposition of pyrite FeS2 in the temperature range 748-834 K. The decomposition proceeded, in a dynamic argon atmosphere, according to the equation FeS2(s) --> FeS(s) + S(g) and was accelerated by mechanical activation in a planetary mill. We have found that reaction is sensitive to defectiveness of the structure of FeS2 and the estimation of its structure sensitivity depends on an adequate choice of the method used for measuring the surface area of the particles. Longer times of mechanical activation bring about the effect of recombination of fine particles of pyrite, which retards the reaction.