Rare earth recovery from fluoride molten-salt electrolytic slag by sodium carbonate roasting-hydrochloric acid leaching

作     者：Hao Wu Huashan Yan Yanzhen Liang Sen Qiu Xiaowen Zhou Dongmei Zhu Tingsheng Qiu Hao Wu;Huashan Yan;Yanzhen Liang;Sen Qiu;Xiaowen Zhou;Dongmei Zhu;Tingsheng Qiu

作者机构：Collaborative Innovation Center for Development and Utilization of Rare Metal Resources Co-sponsored by Ministry of Education and Jiangxi ProvinceJiangxi University of Science and TechnologyGanzhou 341000China Jiangxi Province Key Laboratory of Mining EngineeringJiangxi University of Science and TechnologyGanzhou 341000China School of Resources and Environmental EngineeringJiangxi University of Science and TechnologyGanzhou 341000China 

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

年 卷 期：2023年第41卷第8期

页      面：1242-1249,I0005页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 080603[工学-有色金属冶金] 08[工学] 0806[工学-冶金工程] 0703[理学-化学] 

基　　金：supported by the National Key Research and Development Project of China(2018YFC1903400) Key Research and Development Program of Jiangxi Province(20212BBG73049) Jiangxi Provincial Department of Education Science and Technology Research Project(GJJ190486) Excellent Doctoral Dissertation Cultivating Project of Jiangxi University of Science and Technology(202202400013)。 

主　　题：Fluorinated rare earth molten-salt electrolytic slag Sodium carbonate Roasting Transformation mechanism Leaching Rare earths 

摘      要：Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.