Study of molybdenum extraction by trioctylamine and tributylphosphate and stripping by ammonium solutions

The extraction of molybdenum from an aqueous solution by a tertiary amine extraction system was experimentally studied in this work. The organic phase is composed of trioctylamine (TOA) as the extractant, tributylphosphate (TBP) as the modifier, and kerosene as the diluent. The effects of various parameters including the concentrations of TOA and TBP, initial pH of aqueous phase, phase ratio of organic/aqueous, contact time of phases, type of diluent, and concentration of metal ions in the aqueous phase on the extraction of molybdenum were investigated. At the same time, stripping of molybdenum from the molybdenum-loaded organic phase using an ammonium hydroxide solution as stripping reagent was studied. The results showed that an extraction of 99.9% was obtained with the extraction system composed of 4 vol.% TOA, 12 vol.% TBP, and 84 vol.% kerosene at a phase ratio of 1, initial pH = 1, and contact time = 600 s. The difficulties in separating aqueous and organic phases were successfully obviated through addition of TBP to TOA extractant.