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