Application of Hydrofluoroethers as Diluent to Solvent Extraction of Zinc(II) Using Phosphorus Acid Extractants

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

Fumio Kawaizumi¹  Katsuroku Takahashi¹  Takehiko Kinoshita²  Shigendo Akita²  Susumu Nii¹ 

[1] Department of Chemical Engineering, Nagoya University;Nagoya Municipal Industrial Research Institute

关键词: Hydrofluoroethers;    D2EHPA;    EHPNA;    Zinc Extraction;    Extraction Equilibrium Constant;   

DOI  :  10.1252/jcej.38.94

来源: Maruzen Company Ltd

【 摘 要 】

References(9)Cited-By(3)Hydrofluoroethers have been applied as diluent for phosphorus acid extractants in the solvent extraction of zinc(II). They are promising alternatives to conventional organic diluents because of their non-flammability, chemical stability and non-toxicity. Hydrofluoroethers used in this study are a mixture of ethylperfluorobutylether and ethylperfluoroisobutylether and a mixture of methylperfluorobutylether and methylperfluoroisobutylether (HFE-7100). Among the extractants examined, two phosphorus acid extractants, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and 2-ehtylhexyl phosphoric acid mono-2-ethylhexyl ester (EHPNA) were soluble in both hydrofluoroethers. Because of the high specific gravity of hydrofluoroethers and their low solubility in water, phase-separation was rapid and the resulting phases were clear. In the extraction of zinc(II) using the phosphorus acids, the system with D2EHPA gave higher extraction than that with EHPNA, while there was little difference in the extraction behavior between the two hydrofluoroethers. The effects of the equilibrium solution pH and the extractant concentration on the zinc extraction were examined, and the stoichiometric relationship for the extraction was proposed. The extraction equilibrium constants for zinc(II) were found to be higher than those with conventional chlorinated organic solvents such as chloroform and carbon tetrachloride. The backward extraction of zinc(II) was satisfactorily attained with a dilute acid solution, and the separation of several heavy metals was also demonstrated. Moreover, the elution of the extractants and hydrofluoroethers into the aqueous phase was very low, and this makes the present system more attractive.

【 授权许可】

Unknown