络合法除P507-N235体系中铁的研究  

Removal of Fe(Ⅲ) from P507-N235 System by Complexing Method

作　　者：蓝桥发[1,2] 黄振华[1] 谢芳浩[1] 杨幼明[1,2] 

机构地区：[1]江西理工大学工程研究院,江西赣州341000 [2]国家离子型稀土资源高效开发利用工程技术研究中心,江西赣州341000

出　　处：《中国稀土学报》2015年第2期188-195,共8页Journal of the Chinese Society of Rare Earths

基　　金：国家高技术研究发展计划项目(2012AA061901)资助

摘　　要：因铁离子具有强烈的水解倾向及易与其他离子形成配合物的性质,在溶剂萃取体系中的存在形式极为复杂。在稀土萃取体系中,采用P204或N235除铁,经盐酸反萃后,有机相中铁的反萃率较低,不能深度除去,影响萃取剂的萃取性能。而在P507-N235盐酸萃取体系中,Fe3+在低酸度下可被P507萃取,在高酸度下形成Fe Cl-4配合物被N235萃取,萃取率达99%以上,且难被反萃下来。研究采用草酸和EDTA络合法除去有机相中的铁,结果表明:草酸络合法除铁率较低,较难用草酸络合法将有机相中的铁反萃下来;在温度25℃、反萃时间14 min,相比1∶1的条件下,用EDTA络合法除铁,铁的反萃率可达97.51%,经4次错流反萃后,可将有机相中铁的浓度降至0.002 g·L-1,达到深度除铁的目的。Fe^3＋ has an intensive tendency of hydrolysis and is easy to form complexes with other ions,therefore the solvent extraction system containing Fe^3＋is very complex. Using P204 or N235 to remove Fe^3＋in rare earth extrac-tion system,the organic phase with Fe^3＋ was stripped by hydrochloric acid,its stripping rate was low,and it had a deep influence on the ability of the extraction agents. In extraction system of P507-N235 hydrochloric acid,the Fe^3＋in low acidity and the complex of FeCl-4 formed in high acidity were extracted by p507 and N235,respectively,and the extraction rate could reach 99% and was hard to stripping. The removal of Fe^3＋ from the organic phase was investigated by using a complexing method consisting of oxalic acid and EDTA. The results showed that the stripping rate of Fe^3＋was too low by using complexing method of oxalic acid,therefore the oxalic acid couldn＇t be used for the removal of Fe^3＋. At temperature of 25 ℃,stripping time of 14 min,feed phase proportion of 1∶1,the stripping rate of Fe^3＋ could reach 97.51% by using complexing method of EDTA,and the concentration of Fe^3＋ in organic phase could decrease to 0.002 g·L^-1after a four-stage cross-flow stripping.

关 键 词：P507 N235 络合 除铁 草酸 EDTA 稀土 

分 类 号：O6-332[理学—化学]