Non-isothermal oxidation of copper concentrate particles falling in a vertical tube. Effect of composition on the interfacial reaction rate of copper concentrate

Four kinds of copper concentrate of different compositions were oxidized in a N₂-O₂ gas stream. The dependence of the rate of desulphurization on oxygen partial pressure and wall temperature was examined. X-ray diffraction analysis of the cinders showed that copper concentrate was thermally decomposed, and the formed FcS was oxidized to Fe₃O₄. The non-isothermal oxidation of copper concentrate particles was described using an unreacted core model of copper concentrate core covered with an outer product layer of magnetite. The frequency factor k₀ of the interfacial reaction rate constant was determined so as to fit the calculated desulphurization curve to the observation. It was found that the k₀ value significantly decreased with an increase in P_O(2). Moreover, the k₀ for CuFeS₂ was larger, and it decreased with the amount of FeS₂ contained in the copper concentrate.