A novel extractant bis(2-ethylhexyl) ((2-ethylhexylamino)methyl) phosphine oxide for cerium(IV) extraction and separation from sulfate medium

• Published in: Journal of rare earths 2020-12, Vol.38 (12), p.1330-1336
• Main Authors: Huang, Mingxia, Fu, Yongmei, Lu, Youcai, Liao, Wuping, Li, Zhongjun
• Format: Article
• Language: English
• Subjects: Ce(IV); Extraction; Rare earths; Separation; α-aminophosphine oxide
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2019.12.009

By introducing the amine group into phosphorus extractant, a novel aminophosphine compound bis(2-ethylhexyl) ((2-ethylhexylamino)methyl) phosphine oxide (DEHAPO, abbreviated as A) was synthesized for the extraction of cerium (IV) (Ce(IV)) from sulfate medium (H2SO4). The influence factors including extractant concentration, H2SO4 concentration and temperature on the Ce(IV) extraction were investigated and discussed. It is found that the extraction ability of Ce(IV), thorium (IV) (Th(IV)) and rare earths (REs(III)) (La, Gd, Yb) decreases in sulphate medium in the following order: Ce(IV) > Th(IV) > REs(III). The extraction process is an exothermic reaction and the thermodynamic parameters were calculated. The extracted complex of Ce(HSO4)2SO4·A in loaded organic solution was identified by the slope methods and further proved by FT-IR spectral analysis. Stripping studies indicate that Ce(IV) can be effectively stripped from the organic phase. The results of separation factors (β) and saturation loading capacity demonstrate that DEHAPO could be used to selectively extract Ce(IV) from sulphate medium with high separation efficiency and good extraction ability. A novel extractant DEHAPO was synthesized and employed for the recovery and separation of Ce(IV) from Th(IV) and RE (Ⅲ) in sulphuric acid medium. It is clearly seen that the order of extraction ability of these metal ions is Ce(IV) > Th(IV) > REs(III). The extraction percentage of Ce(IV) with DEHAPO is higher than those of Th(IV) and REs(III). [Display omitted] •DEHAPO was synthesized and its structure was characterized by 1HNMR, MS and IR.•The extractant can be used to selectively separate Ce(IV) from Th(IV) and RE (III) in sulfate medium.•The extraction mechanism of DEHAPO for Ce(IV) was investigated.•The extraction capacity and regeneration of DEHAPO for Ce(IV) were examined.