首页|In-situ electrochemical study on the effects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation
In-situ electrochemical study on the effects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation
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In-situ electrochemical study on the effects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation
Fe(Ⅲ)has been proved to be a more effective oxidant than dissolved oxygen at ambient temperature,how-ever,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electro-chemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment.The results illustrated that increasing Fe(Ⅲ)concentra-tions led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of ele-mental sulfur.Reduction of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising temperatures.While,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall reaction.Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentra-tions,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.
School of Chemical Engineering,Guizhou Minzu University,Guiyang 550025,China
Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China
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