The Effect Of MnO₂ And FeS₂ On Leaching Of Chalcopyrite

Chalcopyrite is one of the important raw materials for copper smelting and it is also the most refractory sulphide ores.There are problems in the leaching process of chalcopyrite by hydrometallurgy,such as low reaction rate and unclear oxidation leaching mechanism This study investigated the effect of MnO₂ and FeS₂ on the leaching behavior of chalcopyrite at atmospheric pressure and explored the influence of leaching temperature,sulfuric acid concentration and oxidant on the leaching behavior of chalcopyrite with adding MnO₂ or FeS₂ and optimized the experimental conditions.The feasibility and mechanism of improving leaching efficiency by mechanial activation which can increase contact area between FeS₂ and chalcopyrite so that improve the galvanic effect was studied.The electrochemical mechanism of FeS₂ on the leaching behavior of chalcopyrite was studied by electrochemical test.Research indicates:Under atmospheric pressure,MnO₂ is added to the H₂SO₄ system to make contact with the chalcopyrite powder to form a primary battery which can promote the leaching of the chalcopyrite.In the solution,MnO₂ breaks into Mn2+rapidly so that the content of MnO₂ in the solution will decrease at the later stage and the interaction with chalcopyrite will decrease too.In the presence of MnO₂,the leaching temperature,the concentration of H₂SO₄ and the concentration of Fe³⁺ can influence the leaching efficiency of chalcopyrite.Under atmospheric pressure,FeS₂ is added to the H₂SO₄ system to make contact with the chalcopyrite powder to form a primary battery.In H₂SO₄ solution,the presence of FeS₂ can promote the dissolution of chalcopyrite.The sulfur in chalcopyrite is oxidized to elemental sulfur and adheres to the surface of chalcopyrite.The addition of oxidant Fe³⁺ and H₂O₂ will further accelerate the dissolution rate of chalcopyrite.The sulfur in chalcopyrite is oxidized to SO₄^2- which can avoid chalcopyrite wrapped by the sulfur layer.With mechanical milling,FeS₂ contacts with chalcopyrite closely.The effect of FeS₂ on chalcopyrite leaching rate will be better,oxidant of H₂O₂ has the best effective.The results of electrochemical tests shows that FeS₂ can promote the dissolution of chalcopyrite at atmospheric pressure but the formation of passivation film on the surface of chalcopyrite can't be avioded.FeS₂ does not affect the electrochemical mechanism of the leaching behavior of chalcopyrite when the oxidant is air but affect the electrochemical mechanism by the adding Fe³⁺ or H₂O₂.