Solvent extraction and separation of light rare earths from chloride media using HDEHP-P350 system  

作　　者：Wenjie Zhang Dongxia Feng Xian Xie Xiong Tong Yunpeng Du Yang Cao 

机构地区：[1]School of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China

出　　处：《Journal of Rare Earths》2022年第2期328-337,I0005,共11页稀土学报（英文版）

摘　　要：Solvent extraction is the most important method for rare earth extraction and separation.Currently,di(2-ethylhexyl)phosphoric acid(HDEHP)and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester(HEH/EHP)are widely used in industrial production,but there are still obvious deficiencies that require further research to resolve.In this paper,the unsaponification extraction of light rare earth ions in a hydrochloric acid medium by di(2-ethylhexyl)phosphoric acid-di(1-methyl-heptyl)methyl phosphonate(HDEHPP350)system was studied.The results show that the addition of P350 reduces the extraction capacity of HDEHP,and also greatly reduces the concentration of acidity required for the back-extraction.It still has a good separation factor for light rare earths without saponification,and the extractant is not easy to emulsify.With an aqueous phase of pH=2.85,and HDEHP mole fraction XHDEHP=0.9(compared with O/A=2),the separation effect of light rare earth is the best,resulting in the separation coefficientβCe/La=3.39,βPr/Ce=1.67 andβNd/Pr=1.45,respectively.The loaded light rare earth ions extracted by HDEHP-P350 can be easily stripped when 2 mol/L HCl is used as the stripping agent.Finally,the extraction mechanism is discussed using a slope method,and the final structure of the extracted complex is determined to be RECl[(DEHP)_(2)]_(2)P350_((o)),based on a combination of infrared spectra and 1 H NMR and 31P NMR analyses.

关 键 词：HDEHP P350 Extraction Separation Mechanism Rare earths 

分 类 号：TF845[冶金工程—有色金属冶金]