Synergistic extraction and separation of thorium from rare earths in chloride media using mixture of Cextrant 230 and Cyanex 923  

作　　者：Hui Wang Shengting Kuang Wuping Liao 

机构地区：[1]School of Rare Earths,University of Science and Technology of China,Hefei,230026,China [2]Institute of Material and Chemistry,Ganjiang Innovation Academy,Chinese Academy of Sciences,Ganzhou,341000,China [3]State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun,130022,China

出　　处：《Journal of Rare Earths》2024年第4期759-767,共9页稀土学报（英文版）

基　　金：Project supported by the National Key Research and Development Project of China(2022YFC2905201);the Science and Technology Service Network Initiative Program of the Chinese Academy of Sciences(KFJ-STSQYZD-2021-18-001);the Research Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055C002);Jiangxi"Double Thous and Plan"(jxsq.2020101005);Jiangxi Province Natural Science Foundation(20212BAB213033);Ganzhou Science and Technology Program(2022CXRC9671)。

摘　　要：In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.

关 键 词：Synergistic extraction Cextrant 230 Cyanex 923 THORIUM Rare earths 

分 类 号：TF845[冶金工程—有色金属冶金]