中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 3 March 2025 |
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083, China）
Abstract:The distribution and competitive behaviors of phosphotungstic acid and ferric chloride in the TBP–HCl–H2O system were investigated by controlling the extractant concentration and the solution environment. The results revealed that phosphotungstic acid exhibited a strong affinity for TBP with decreasing TBP concentration. Higher acidity significantly improved the W extraction efficiency with TBP, and the lower Cl- concentration reduced the extraction efficiency of Fe. As the organic phase approached saturation point, phosphotungstic acid competitively displaced Fe to combine with TBP. The hydrogen bond structure (P=O·HO—P—W—O) between phosphotungstic acid and TBP was characterized by FT-IR, and the salting-out effect induced by FeCl3 was elucidated. In summary, high acidity is beneficial for exhaustive extraction of W, and an effective W/Fe separation can be achieved by reducing the concentrations of TBP and Cl-.
Key words: solvent extraction; tri-butyl phosphate; tungsten/iron separation; distribution equilibrium; competitive behavior
