Study On Leaching Mechanism And Electrochemistry Of Chalcopyrite In Hydrogen Peroxide And Ethylene Glycol

As an important resource of copper reserves and production,it is difficult to effectively leach under atmospheric conditions.In this study,the influence of sulfuric acid concentration,leaching temperature,hydrogen peroxide concentration and glycol concentration on the leaching behavior of chalcopyrite in H2SO4-H2O2-glycol solution under atmospheric pressure was investigated.The leaching mechanism of chalcopyrite in H2SO4-H2O2-glycol solution was studied by electrochemical test.Take modified cathode in combination with different anode electrolysis to produce hydrogen peroxide online to study the feasibility of producing hydrogen peroxide in situ to leach chalcopyrite.Then take X-ray diffraction(XRD)and scanning electron microscope(SEM)to clarify the oxidation leaching mechanism of chalcoprite in H2SO4-H2O2-glycol solution.Chalcopyrite can be effectively leached from H2SO4-H2O2-glycol solution under normal pressure.The addition of Fe3+ can accelerate the decomposition of hydrogen peroxide and thus reduce the leaching rate of chalcopyrite.Ethylene glycol can effectively inhibit the decomposition of hydrogen peroxide in the leaching solution,so as to improve the leaching rate of chalcopyrite.The decomposition rate of hydrogen peroxide increased with the increase of leaching temperature,concentration of hydrogen peroxide and concentration of Fe3+,and the increase of solution acidity was beneficial to inhibit the decomposition of hydrogen peroxide.The main reasons for inhibiting chalcopyrite leaching were the consumption of hydrogen peroxide in the leaching solution,which lead to the reduction of the oxidization of the leaching solution,and the large amount of elemental sulfur coating generated by chalcopyrite leaching,which hindered the contact between the leaching solution and chalcopyrite.The results of Kinetic study show that the behavior of leaching of chalcopyrite in H2SO4-H2O2-glycol solution deviating from the chemical reaction control,It is the diffusion control of the leaching solution in the solid product or diffusion control of leach in solid products and Mixing control of hydrogen peroxide concentration,reaction apparent activation is 23.72 kJ/mol,Verify of the leaching of chalcopyrite in H2SO4-H2O2-glycol solution main influence by the decomposition of hydrogen peroxide and the package of elemental sulfur.In this paper,modified graphite felt,porous titanium mesh anode,platinum,carbon plate and titania-based coating materials were used as electrodes to prepare hydrogen peroxide on line.The results indicate that The efficiency of preparing hydrogen peroxide was different at different electrodes,and the content of hydrogen peroxide decreased sharply with the decrease of pH value of the solution.Take modified graphite felt and modified oxygen cathode with different anodes in homemade electrolyzerto preparation of hyd rogen peroxide by electrolysis.The copper ions that were leached would deposit in the cathode,resulting in a low concentration of copper ions in the leaching solution.There are three obvious time constants of chalcopyrite electrode in H2SO4-H2O2-glycol solution.The principle of choosing the equivalent circuit includes choosing the least equivalent circuit model with corresponding physical significance.Therefore,the equivalent circuit models with three time constants are selected in this paper,which are respectively Corresponding to the solution resistance in the reaction system,the capacitance and resistance of the space charge layer on the surface of chalcopyrite electrode,the capacitance and resistance corresponding to the charge transfer of chalcopyrite leaching reaction and the capacitance and resistance of passivation film and hydrogen peroxide oxygen decomposition.The increase of the concentration of ethylene glycol and sulfuric acid increased the impedance corresponding to the decomposition of hydrogen peroxide and oxygen.The increase of Fe3+ concentration,the rise of leaching temperature and the increase of hydrogen peroxide concentration reduced the impedance corresponding to the decomposition of hydrogen peroxide and oxygen,which was consistent with the results of leaching experiment.