Enhanced Leaching Microscopic Mechanism Of Chalcopyrite With Mechanical Activation And Redox Potential Regulation

20%of the world’s copper is produced by hydrometallurgy,but chalcopyrite leaching is slow and the leaching efficiency is low.Many researches have shown that mechanical activation pretreatment can improve chalcopyrite leaching.In this paper,chalcopyrite was investigated as an object of research,and the changes in the physicochemical properties and internal crystal structure of the mineral caused by mechanical energy under different mechanical activation conditions,as well as the laws affecting its electrochemical and leaching behaviour,to identify the mechanism of enhanced chalcopyrite leaching by mechanical activation.The main conclusions of this paper are as follows:（1）The particle size of chalcopyrite decreased significantly after mechanical activation,with D50 decreasing from 10.28μm to 2.91μm.XRD analysis shows that the intensity of the activated chalcopyrite diffraction peak decreases,the diffraction peak broadens,the grain size decreases from 1937（?）to 301（?）,while the microscopic strain changes from 0%to 0.3486%and the cell volume expands further.（2）The synergistic control of mechanical activation and potential can significantly increase the chalcopyrite leaching rate,where the activation speed of 400 rpm chalcopyrite leaching rate in the Fe³⁺=0.1 mol/L system was 3.76 times higher than that of unactivated chalcopyrite,with only chalcopyrite and singlet sulphur present in the leaching residue.Chalcopyrite can be leached in suitable potential range with higher leaching rate.The leaching kinetic results showed that mechanical activation significantly reduced the reaction activation energy,where the activation energy of chalcopyrite in the Fe³⁺=0.1 mol/L system decreased from 90.98 k J/mol to 62.83 k J/mol.（3）Electrochemical tests show that chalcopyrite oxidation and reduction peak currents are increased to varying degrees after mechanical activation,chalcopyrite electron transfer rate is accelerated,corrosion potential is reduced,polarization resistance is decreased,corrosion current and corrosion rate are increased,charge transfer resistance is reduced and electrochemical activity is enhanced.（4）Mott-Schottky curves and XPS results show that mechanical activation obviously changes the chalcopyrite energy band structure,the conduction band and valence band positions are positively shifted,the top of the chalcopyrite valence band is closer to the E_redoxvalue of Fe³⁺/Fe²⁺after mechanical activation,which means that the Fe³⁺can capture electrons from the chalcopyrite surface and be reduced,i.e.activated chalcopyrite can react with Fe³⁺in redox reaction.