A new method for preparation of RE_(2)(CO_(3))_(3) by multi-membrane electroconversion  

作　　者：Guixia Fan Jiahong Sun Yijun Cao Jiang Liu Yukun Huang Long Wang 

机构地区：[1]Zhongyuan Critical Metals Laboratory and School of Chemical Engineering,Zhengzhou University,Zhengzhou,450001,China [2]The Key Lab of Critical Metals Minerals Supernormal Enrichment and Extraction,Ministry of Education,Zhengzhou,450001,China [3]Key Laboratory of Ecological Metallurgy of Multi-Metal Intergrown Ores of Ministry of Education,School of Metallurgy,Northeastern University,Shenyang 110819,China

出　　处：《Journal of Rare Earths》2025年第4期822-831,I0007,共11页稀土学报(英文版)

基　　金：supported by the Postdoctoral Research Project of Henan Province (HN2022004);Zhongyuan Critical Metals Laboratory(GJJSGFYQ202319,GJJSGFYQ202328);Open Fund project of Key Laboratory of Ecological Metallurgy of Multi-Metal Intergrown Ores of Ministry of Education(NEMM2022003);Guangxi Science and Technology Major Project (Guike AA22068078);National Key R&D Program of China (2021YFC2902604)。

摘　　要：Preparing rare earth carbonates from rare earth chlorides is a common step in the smelting process for all rare earth ores;however,it produces large amounts of ammoniacal nitrogen wastewater and a chloriderich precipitate.This study proposes a novel,green and simple process for preparing low-chlorine lanthanum carbonate via a multi-membrane electroconversion approach.The effects of the CO_(2) flow rate,current density,lanthanum chloride concentration,and electroconversion time on the electroconversion process were systematically explored.Under the optimal process conditions(CO_(2) flow rate=0.5 L/min,current density=25 mA/cm~2,LaCl_(3) concentration=0.3 mol/L,electroconversion time=60 min),a current efficiency of 75.77% was obtained,along with a unit energy consumption of5.44 kWh/kg.X-ray diffraction,Fourier transform infrared spectroscopy,thermogravimetric analysis,and laser particle size analysis results indicate that a pure La_(2)(CO_(3))_(3)·8H_(2)O product is obtained with a median particle size of 6.53 μm and chlorine content of 0.0021%.In addition,scanning electron microscopy and transmission electron microscopy observations indicate that the crystallisation and growth of La_(2)(CO_(3))_(3)·8H_(2)O conform to the oriented attachment and Ostwald ripening mechanisms.Thus,the proposed multi-membrane electroconversion method provides guidance toward the clean transformation of rare earth chlorides to low-chlorine lanthanum carbonates.

关 键 词：Rare earths Carbon dioxide Electroconversion Lanthanum carbonate Crystallisation mechanism 

分 类 号：TF845[冶金工程—有色金属冶金]