Abstract: Study is made on the electrochemical behavior of chalcopyrite in sulfuric acid leaching of natural chalcopyrite by three-electrode method. The results indicate that the chalcopyrite is first oxidized into iron-depleted sulfide, which covers the electrode surface and passivates the latter. With the rise in potential, the iron-depleted sulfide continues the oxidation and finally occurs in the solution in form of sulfate radical. When the potential gets smaller than -0.85 V (vs.SCE), the cathodic reduction current of chalcopyrite is larger and the Fe³⁺ in the crystal lattice is fully dissolved. The strong cathodic reaction of chalcopyrite is of great importance to the oxidation-leaching of chalcopyrite. What's more, with the decrease of pH, H₂S formation is accelerated and the peak current of oxidation reduction is increased, indicating that the reduction of pH of the said research system is beneficial to the oxidation of chalcopyrite.

Key words: Chalcopyrite, Cyclic voltammetry, Electrochemistry, Acid leaching