Kinetic study on bastnaesite concentrate mechanochemical decomposition in NaOH solution

作     者：Jiang Liu Zhihe Dou Ting’an Zhang Jiang Liu;Zhihe Dou;Ting'an Zhang

作者机构：Key Laboratory of Ecological Metallurgy of Multi-Metal Intergrown Ores of Ministry of EducationSchool of MetallurgyNortheastern UniversityShenyang 110819China 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2020年第38卷第4期

页      面：418-426页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 07[理学] 070304[理学-物理化学(含∶化学物理)] 0708[理学-地球物理学] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：Project supported by the Fundamental Research Funds for the Central Universities(N172506009,N170908001,N182515007,N180725023) National Natural Science Foundation of China(U1508217). 

主　　题：Bastnaesite concentrate Mechanochemical decomposition Sodium hydroxide Kinetics Rare earths 

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.