Kinetic study on bastnaesite concentrate mechanochemical decomposition in NaOH solution
来源期刊：Journal of Rare Earths2020年第4期
论文作者：Jiang Liu Zhihe Dou Ting’an Zhang
文章页码：418 - 426
摘 要：Mechanochemical reaction involves simultaneous chemical reaction and particle crushing;the latter increases the effective reaction area and improves the reactivity,thus enhancing its kinetics.The classical shrinking core model was used to model the kinetics of bastnaesite mechanochemical decomposition in NaOH solution,which shows a questionable result.Mechanochemical reaction is a dynamic process,where the particle shape and concentration in reaction interface undergo constant change.Thus,a physically consistent model was applied to describe the kinetics.The variations in OH-concentration and particle shape were considered in the revision of model.Considering the variation in OH-concentration in solution with time,the model with varying OH-concentration agrees better with the experimental data,improving the regression coefficients to between 0.936 and 0.992.By introducing fractal geometry to deal with the irregular system,the model was further optimized,and the regression coefficients increase to between 0.940 and 0.997.All these models considere shrinking particle approaches and controlling mechanisms for the diffusion and chemical reaction.Finally,the fractal model with varying OH-concentration was selected to describe the mechanochemical decomposition of bastnaesite,which indicates that the process is controlled by chemical reaction.
Jiang Liu，Zhihe Dou，Ting’an Zhang
Key Laboratory of Ecological Metallurgy of Multi-Metal Intergrown Ores of Ministry of Education, School of Metallurgy, Northeastern University
摘 要：Mechanochemical reaction involves simultaneous chemical reaction and particle crushing;the latter increases the effective reaction area and improves the reactivity,thus enhancing its kinetics.The classical shrinking core model was used to model the kinetics of bastnaesite mechanochemical decomposition in NaOH solution,which shows a questionable result.Mechanochemical reaction is a dynamic process,where the particle shape and concentration in reaction interface undergo constant change.Thus,a physically consistent model was applied to describe the kinetics.The variations in OH-concentration and particle shape were considered in the revision of model.Considering the variation in OH-concentration in solution with time,the model with varying OH-concentration agrees better with the experimental data,improving the regression coefficients to between 0.936 and 0.992.By introducing fractal geometry to deal with the irregular system,the model was further optimized,and the regression coefficients increase to between 0.940 and 0.997.All these models considere shrinking particle approaches and controlling mechanisms for the diffusion and chemical reaction.Finally,the fractal model with varying OH-concentration was selected to describe the mechanochemical decomposition of bastnaesite,which indicates that the process is controlled by chemical reaction.
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