节点文献
HDEHP和HEH/EHP混合萃取剂在硫酸介质中协同萃取RE(Ⅲ)的机制研究
Synergistic Extraction of Rare Earths by Mixture of Di-(2-ethylhexyl) Phosphoric Acid (HDEHP) and 2-Ethylhexyl Phosphoric Acid Mono-2-Ethylhexyl Ester (HEH/EHP) in Sulfuric Acid Medium
【摘要】 对HDEHP(H2B2)和HEH/EHP(H2L2)混合萃取剂在硫酸介质中萃取稀土元素(La,Nd,Sm,Gd)的机制进行了研究。研究表明,在水相平衡pH=2.0时,混合萃取剂萃取这几种元素的协萃系数分别为:1.96(La),3.52(Nd),5.96(Sm),5.71(Gd),并且协萃系数随水相平衡pH的升高而增加。利用斜率法分别确定了单一萃取剂HDEHP和HEH/EHP以及混合萃取剂HDEHP+HEH/EHP在硫酸体系中萃取稀土元素的配合物结构式分别为RE(SO4)xH2x(HB2)3,RE(SO4)xH2x(HL2)3以及RE(HB2)2(HL2)。计算了反应的平衡常数及形成常数并确定了反应机制为阳离子交换反应。
【Abstract】 The extraction of RE(Ⅲ)(RE=La,Nd,Sm,Gd) in sulfuric acid medium using mixture of HDEHP(H2B2) and HEH/EHP(H2L2) was investigated.The synergistic enhancement coefficients(R) was calculated for La(1.96),Nd(3.52),Sm(5.96),Gd(5.71) respectively at pH=2.0,and R increased with the increase of aqueous equilibrium pH.The configuration of the extracted complexes was considered to be RE(SO4)xH2x(HB2)3 with HDEHP,RE(SO4)xH2x(HL2)3 with HEH/EHP,and RE(HB2)2(HL2) with their mixture as the extractant by the slope method.The equilibrium constants and stability constants were calculated.A cation exchange mechanism was proposed as well.
【Key words】 HEH/EHP; HDEHP; synergistic; extraction; sulfuric acid; rare earths;
- 【文献出处】 中国稀土学报 ,Journal of the Chinese Rare Earth Society , 编辑部邮箱 ,2008年06期
- 【分类号】TF845.6
- 【被引频次】10
- 【下载频次】295