Separation of macro amounts of tungsten and molybdenum by precipitation with ferrous salt

In order to develop a low-cost approach for separating macro amounts of Mo and W, the effects of parameters on the separation using FeSO4 as precipitation reagent were studied. The results show that the optimum reaction temperature is 10°C, and the separation factor does not further improve after a reaction time of 7 h. Moreover, slow dropping speed of the precipitation reagent is beneficial for improving the separation efficiency. When the H+/W molar ratio is below 1/1, the addition of acid to a neutral solution is favorable to the separation. For the solution with an ammonium concentration below 3 mol/L, the separation factor is high due to the high W-precipitation rate. Furthermore, the method is also effective when it is applied to industrial solution containing some other impurities. All these indicate the ferrous salts have great potential for removing W from Mo on a commercial scale.