LLC “Scientific-research center “Gidrometallurgiya”, Saint-Petersburg, Russia:

Ya. M. Shneerson, Chief Executive Officer

A. V. Markelov, Researcher

L. V. Chugaev, Leading Researcher

A. S. Kabisova, Engineer

Great difficulties in modeling of autoclave oxidation processes consist in accurate determination of mineral surface during the process. Currently there are several widely used kinetics models, taking into account the change in the surface of oxidized material, such as shrinking core model or population balance. Each one has its own advantages and disadvantages. In this work, there was used the kinetics function model, developed by E. M. Vikdorchik and A. B. Sheinin in early 1970-s. This model was adapted for high temperature POX process. On the basis of this model, the kinetic parameters for 13 flotation concentrates were calculated for the temperature range of 190–230 ºC and oxygen partial pressures of 0,3–0,9 MPa. The concentrates differed by the content of pyrite, arsenopyrite and pyrrhotite. The following kinetics parameters were calculated for each material: kinetic function, reaction order, activation energy. Chemical reaction was the rate-limiting step for all materials. All activation energies were within the range of 40–90 kJ/mole. The reaction order for concentrates with over-representation of pyrite and arsenopyrite ranged from 0,7 to 1. Reaction order for concentrates with over-representation of pyrrhotite ranged from 0,6 to 0,9. Kinetics characteristics and kinetic function can be used for the continuous process modeling. The resulting mathematical model quite accurately describes the results of real pilot plant test, so this model can be used for industrial implementation and industrial autoclave calculations. The gold recovery on cyanidation after POX for all concentrates is more than 94%.

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