The method of recovery the refractory sulfide ores with the aid of pressure oxidation was examined. The basic processes of oxidation was discovered and the mathematical description of the process of sulfide oxidation in a heterogeneous system, the liquid – solid, was suggested. The ReactOp allowed to solve inverse problem – determination of kinetic parameters (E = 112 kJ/mol, ln(K) = 20 m/s) from the experimental data. On the basis of defined parameters is made and investigated the cascade of continuous stirred-tank reactors.