Abstract:The kinetics of the catalytical oxidation acid leaching of arsenopyrite is studied in the HNO₃-H₂SO₄-O₂ aqueous system. In addition to the effect of reaction time on the extraction of arsenopyrite and distribution of products, the effects of operation factors and several additives on the reaction rate are also investigated. The experi mental results show that the oxidation rate is greatly dependent on nitric acid concentration, average radius of samples and acid concentration. The elemental sulphur produced does not interfere with the progress of the reacation process. It is found that a shrinking core model with chemical reaction controlling, which is expressed as 1-1-α(1/3)=kt, may be adopted to describe the kinetics results. The apparent activation energy is tested to be 23. 6 kJ/mol.

Key words: arsenopyrite catalytical oxidation acid leaching addifives