In order to separate tungsten and molybdenum, people studied the methods of ion exchange method and solvent extraction. These methods are mainly used for depth from tungstate solution to remove a small amount of impurity molybdenum or from acid salt solution depth to remove a small amount of impurities in tungsten. When high impurities content of molybdenum and tungsten in the solution, the above method is difficult to apply. But the method of using alkalescent anion exchange resin can effectively eliminating the molybdenum from sulfurized sodium tungstate solution.

 

It is well known that the affinity of molybdenum for sulfur is far greater than the affinity of tungsten for sulfur. Under the condition of weak alkaline, MoO2-4 can be vulcanized to sulfur acid radical ion preferentially. While tungsten still exists in the form of WO2-4. MoOxS2-4 - x has a strong affinity to the alkalescent anion exchange resin. The stronger the alkaline of resin is, the bigger of the affinity of MoOxS2-4 - x. But when MoOxS2-4 – x was adsorbed with strongly alkalescent anion exchange resin, MoOxS2-4 - x are difficult to desorption. The antioxidant of sodium hypochlorite or hydrogen peroxide must be added in desorption agent. MoOxS4 - x can be adsorbed after oxidation. This not only increases the difficulty of operation, but also causes the oxidation of resin. 

 

While the resin adsorption capacity of molybdenum is very small, MoOxS2-4 - x is easy to be adsorbed by NaOH solution so as to overcome the desorption difficulty. How to further improve the resin adsorption capacity of aluminum will has a good application prospect. According to the ion exchange equilibrium principle, the adsorption capacity of ion exchange resin will become bigger with the increase of the ion adsorption equilibrium concentration in the solution. So the adsorption and desorption behavior of alkalescent anion exchange resin in sodium tungstate solution can improve the adsorption capacity of resin and has the value of industrial application. 

 

According to this method we can draw the following conclusions:

1. The resin adsorption capacity of molybdenum significantly increases when molybdenum concentration is higher by using alkalescent anion exchange resin method to adsorb MoOxS2-4 – x. And in the dynamic adsorption, the adsorption capacity of molybdenum can also achieve high value and has practical value. At the same time, the resin can be desorbed by using the NaOH solution of 1.0mo/L concentration. The rate of desorption achieves 97.3%.

2. About the tungsten acid salt solution including molybdenum and sodium carbonate, the molybdenum adsorption rate and adsorption capacity can be significantly improved by using NaHS as vulcanizing agent. Thus it overcomes the adverse effect of molybdenum adsorption efficiency by reason of the competitive adsorption of carbonate ions. 

3. Because sulfur acid radical ion to WO2-4 displacement process exists within the ion exchange column, the adsorption capacity and the effect of eliminating molybdenum in the process of dynamic adsorption were better than the static adsorption process. As a result, the method of using alkalescent anion exchange resin can effectively eliminating the molybdenum from sulfurized sodium tungstate solution.