The New Technology For Separation Of Tungsten And Molybdenum By Ion Exchange

Separation macro tungsten and molybdenum in solution has become an urgent problem to be solved, in tungsten and molybdenum metallurgy technology.It was investigated in this paper that to adjust the pH of the solution which contained macro tungsten and molybdenum (the molar concentration Ratio of WO3and Mo to1/1) to suitable value, the WO42-was polymerized, however, MoO42-was not. Then the polymerized tungsten and MO42-were separated by the proper macroporous anion resin.The main content of the research can be summarized as following:1) In the acidification experiment, it was found that the WO42-was polymerized at pH=7.5, but the MoO42-at pH=5.8when sodium tungsten solution and sodium molybdate solution were acidized respectively. Both to be polymerized, there was a ApH and the Wo42-was polymerized more easily than MoO42-. Through the resin selection, it was found that D213and D308resin was superior to other resins to separate low concentration of tungsten and molybdenum; D201and D309was superior to other resin to separate high concentration of tungsten and molybdenum.2) By the separation experiment, the conclusion was drawed that the best conditions for separating tungsten and molybdenum for D213, D308and D309were below:the solution pH at7.0,4h for the reaction equilibrium time; for D201, the solution pH at8.0,4h for the reaction equilibrium time.3) Desorption of10minutes, tungsten and molybdenum on D201and D213resins could be desorbed easily using1mol/LNaOH,3mol/L NaCl mixture desorption agent; The0.5mol/L NaOH solution to desorb tungsten and molybdenum from D308and D309was used, and the desorption equilibrium time for D308was10minutes, but D309was more than60minutes.4) Isotlermal process and kinetics were studied in this paper. The isotherm models of the four resins for absorbing tungsten were all Langmuir model. For absorbing Mo, the isotherm models of D213and D308were Henry model; D201and D309were both in accordance with Freundlich model. Also, their corresponding function were obtained in this paper. The control steps of adsorbing of tungsten and molybdenum for strong base resin D201were both particle diffusion control(PDF), while the adsorption reaction of tungsten belongs to the endothermic reaction with the activation energy of16.005kJ/mol. The control steps of adsorbing of tungsten for weakly base resin D309was also particle diffusion control (PDF), and its reaction belongs to the endothermicl reaction too, with the activation energy of20.555kJ/mol.5) In order to separate tungsten and molybdenum more effectively, the breakthrough curves had been obtained. It was indicated that no matter the concentration of tungsten and molybdenum were low, or high, compared to the strong basic anion exchange resin,weakly basic anion exchange resin t has better separation effect.In general, the solution with Mo/WO3≥50and the solution with WO3/Mo≥20can all be processed to produce qualified molybdenum and tungsten products respectively by present molybdenum, tungsten production process. Therefore, from the experimental results, it can be found the D213, D308and D309resins have good application prospect for the separation of macro tungsten and molybdenum in solution.