Separation of tungsten and molybdenum in dilute hydrochloric acid solution by extraction with sulfoxides

By using di-n-butylsulfoxide and petroleum sulfoxide as extractants, the extraction behavior of tungsten and molybdenum in hydrochloric acid solutions was studied under different acidities. When acidity is low, molybdenum is preferentially extracted, the selectivity can be very high, and the separation of these two metals is considered favorable. The separation was confirmed by dissolving in dilute hydrochloric acid the combined oxides of both metals, which were obtained from the acid leaching liquor of scheelite. From the experimental curves the molecular ratios of the complexing reaction were analyzed and the neutral molecular complex mechanism was discussed.