Mass Transfer of Molybdenum in L35 + Sodium Sulfate + H 2 O Aqueous Two-phase System with a Packed Column

Abstract The mass transfer characteristics of molybdenum in a packed extraction column using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer surfactant (L35) + sodium sulfate + H 2 O aqueous two-phase system was studied. The hold up of dispersed phase ( e D ) and the overall volumetric mass transfer coefficient of the dispersed phase ( K D a ) were measured with three kinds of packings, such as ceramic rasching rings, metal θ rings and glass springs under different conditions. The experimental results showed that the hold up of dispersed phase increases with increasing the flow rate of the dispersed phase, and decreases with the increase of the tie line length ( TLL ), and increases as increasing the void fraction of the packings. The mean residence time and the Peclet number of the dispersed phase decrease, showing that the axial diffusion extent of the dispersed phase become more serious with increasing the rate of dispersed phase and TLL , and increase with the increase of the void fraction of packing bed according to the sequence of ceramic raschig rings – glass springs – metal θ rings. The overall volumetric mass transfer coefficient of dispersed phase increases with the increase of the rate of dispersed phase and continuous phase and the specific area of three kinds of packings, and decreases with increasing TLL and operating temperature. The mass transfer resistance of two phases is not disregarded.