二-(2-乙基己基)磷酸与仲壬基苯氧基取代乙酸混合体系对稀土元素的萃取

Solvent Extraction of Rare Earths with Mixtures of Di-(2-ethylhexyl) Phosphoric Acid and sec-Nonylphenoxy Acetic Acid

考察了二-(2-乙基己基)磷酸(D2EHPA,H2A2)和仲壬基苯氧基取代乙酸(CA100,H2B2)混合体系在HCl介质中对15种镧系元素(除钷)及钇的萃取性能,计算了稀土元素间的分离系数,并比较了混合萃取体系与D2EHPA单独萃取体系对稀土元素的分离能力。研究了D2EHPA-CA100混合体系对镧的协同萃取机理,用斜率法和恒摩尔法探讨了萃取反应方程式,考察了酸度、萃取剂浓度及温度对萃取性能的影响。结果表明:D2EHPA-CA100混合体系对镧系元素的协同效应随原子序数的增加而减弱。在适当的萃取剂配比下,此混合体系对某些稀土元素的分离能力优于D2EHPA,可用于这些稀土元素的分离。D2EHPA-CA100混合体系协同萃取镧的萃合物组成为LaH5A6B2,反应为吸热反应。

The solvent extraction of rare earths with mixtures of di-（ 2-ethylhexyl ） phosphoric acid （D2EHPA, H2A2） and sec-nonylphenoxy acetic acid （CA100, H2B2） has been carried out. The separation abilities among rare earths were determined and compared with those with D2EHPA alone. The mechanism of synergistic extraction of lanthanum was discussed. The methods of slope analysis and constant mole were used to examine the extraction stoiehiometry. Effects of acidities, concentrations of extraetants, and temperature on the extraetabilities have been investigated. The results showed that the synergistic effects decrease with increasing atomic numbers of rare earths. At proper ratios of the extraetants, the separation abilities of some rare earths with D2EHPA ＋ CA100 were higher than those with D2EHPA alone, which may be applied to the separation of these rare earths. The extracted complex of lanthanum with D2EHPA ＋ CA100 was determined as LaH5A6B2. The synergistic extraction is endotherlnieally driven.