Precursor solution prepared by evaporation deamination complex method for solvent separation of Mo and W by H2O2-complexation
(1. School of Metallurgical Science and Engineering, 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)
2. Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals,Central South University, Changsha 410083, China)
Abstract: An novel method on preparation of precursor solution for solvent separation of molybdenum (Mo) and tungsten (W) by hydrogen peroxide (H2O2)-complexation from the ammonium tungstate solution containing high Mo was studied. The precursor solution was obtained via evaporation deamination and H2O2-complex transformation processes. Then it was extracted with a mixture extractant of tri-alkyl phosphine oxide (TRPO) and tributyl phosphate (TBP) to separate Mo and W. The results indicated that the evaporation deamination complex method reduced the acid consumption by more than 90% in comparison with the traditional directly acid regulation complex method. The transformation rates of W and Mo were higher than 95% and the decomposition rate of H2O2 was less than 15% at a 1.8-1.9 times H2O2 dosage, 45-50 °C, initial pH of 1.80-1.90, and transformation volume ratio of 100% for 60 min in the H2O2-complexation transformation process. The minimum extraction rate of W was 2%, the maximum extraction rate of Mo was 82.6% and the highest separation coefficient was 76.7 in a single-stage extraction.
Key words: tungsten; molybdenum; solvent extraction separation; precursor solution; H2O2