| Sulfide inclusion type refractory gold deposit is the most common type of refractory gold deposit-mainly pyrite and arsenopyrite type gold deposit.When leaching this kind of gold ore,arsenopyrite wrapped on the surface of gold ore needs to be oxidized to further leach gold,so strengthening the oxidation of arsenopyrite is very important.In this paper,the galvanic interaction of pyrite arsenopyrite is used to strengthen the leaching of arsenopyrite.The pure mineral leaching test of pyrite-arsenopyrite mixed ore was carried out.The surface morphology and phase change rule of arsenopyrite enhanced leaching process were analyzed by XRD and SEM.The effects of different factors on the electrochemical kinetics and electrochemical mechanism of surface oxidation of arsenopyrite were studied by electrochemical experiments.The main conclusions are as follows:（1）The results of open-circuit potential,galvanic potential and galvanic current tests of arsenopyrite and pyrite under different factors show that increasing temperature increases c(Fe3+):c(Fe2+)and increasing the bacterial concentration,the open circuit potential of arsenopyrite and pyrite decreases,and the galvanic potential of arsenopyrite is closer to the open circuit potential of arsenopyrite,and the galvanic current density of arsenopyrite increases,indicating that the reaction between pyrite and arsenopyrite galvanic interaction is enhanced,thus accelerating the oxidation dissolution of arsenopyrite.（2）Cyclic voltammetry experiment showed that adding bacteria,adding pyrite,increasing temperature and increasing c(Fe3+):c(Fe2+)increases the elemental sulfur generated by surface reaction of arsenopyrite and improves the oxidation degree of arsenopyrite.Increasing the concentration of bacteria increases As2S2Further oxidation reduces the formation of passivates on arsenopyrite surface.It promoted the oxidation of arsenopyrite.Ac impedance experiments show that the coupling of pyrite and arsenopyrite and the increase of temperature reduce the electron transfer impedance of the initial oxidation of solution impedance and arsenopyrite,and further promote the oxidation of arsenopyrite.Increasing the c(Fe3+):c(Fe2+)reduces the electron transfer impedance of solution impedance and initial oxidation of arsenopyrite,and the thickness of product layer on electrode surface decreases,which promotes the oxidation of arsenopyrite.Bacterial concentration is 1×107 and 3×107cells/m L and 1×108 and2×108cells/m L has different mechanism.The former reduces the solution impedance and the electron transfer impedance of the initial oxidation of arsenopyrite with the increase of bacterial concentration,and promotes the oxidation of arsenopyrite.The latter is that the sulfur-rich layer on the surface is consumed faster with the increase of bacterial concentration,which promotes the oxidation of arsenopyrite.Prolonging the galvanic interaction time can effectively reduce the electron transfer impedance of the initial oxidation of arsenopyrite,reduce the thickness of the product layer on the electrode surface,and promote the oxidation dissolution of arsenopyrite.（3）The results of the mixed leaching test of pyrite and arsenopyrite under bacteria and sterile system show that the enhancement of pyrite on arsenopyrite oxidation in sterile system is only related to galvanic interaction between them;The leaching rate of arsenopyrite was improved with the increase of pyrite addition.Arsenic leaching rate increases and leaching rate increases with the addition of pyrite.When arsenopyrite and pyrite were added 0.8g+1.2g and 1g+1g,the arsenic leaching rate reached the maximum value on the 7th day of leaching,which was 76.84%and 66.88%,respectively,and increased by 60.68%and 57.79%compared with that without pyrite.When the addition of arsenopyrite and pyrite is 1.2g+0.8g,the arsenic leaching rate reaches the maximum on the 9th day of leaching,and the leaching rate is 54.09%,which is 47.19%higher than that without pyrite. |
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