It’s an important and urgent problem of realizing tungsten and molybdenum separation from sodium tungstate solution in tungsten and molybdenum metallurgy. Molybdenum sulfide precipitation separating tungsten and molybdenum from sodium tungstate solution achieves good effect. The influence of the experiment shows in the following aspects:

1. One of the key of molybdenum sulfide precipitation separating molybdenum and tungsten is complete degree of molybdenum sulphur generation. The pH of the solution is the main factor affecting sulphur generation effect. The effect of molybdenum sulphur generation reduces with the increase of pH value. After adding sodium sulphide in solution, when pH value is less than 9.0, the Mo/WO₃ < 0.02, separation effect of tungsten and molybdenum is good. 

 

2. This experiment solution contains much molybdenum. If vulcanizing agent is excessive, there will be a lot of vulcanizing agent joining the solution. Because tungsten content closes to molybdenum content in the solution, it will inevitably lead to tungsten sulphur generation. Tungsten content in precipitation is higher. As a result, adding amount of sodium sulphide should reduce the tungsten sulphur generation. Because of molybdenum and sulphur generation reaction equilibrium constant is much larger than tungsten sulfide reaction equilibrium constant, plus a high molybdenum concentration in the solution, when adding no more than molybdenum sulphur generation theory for the reaction of sodium sulphide, the reaction of molybdenum sulphur generation will proceed fast. This can more effectively precipitate and remove the molybdenum while tungsten remains in the solution.

 

3. To remove a small amount of molybdenum in sodium tungstate solution, sulphur generation time can be extended to remove molybdenum. But for this test material, due to the high molybdenum concentration in the solution, molybdenum sulphur generation reaction speed is faster. Within the time range of the test, the time of sulphur generation has no obvious influence on separation effect of tungsten and molybdenum. 

 

Above all, we can draw the following conclusions:

1. By controlling a certain condition, the molybdenum sulfide precipitation can effectively separate tungsten and molybdenum from sodium tungstate solution. After the separation of tungsten and molybdenum by this method, the adjustable acid Mo/WO₃ drops to around 0.03. Molybdenum content can reach 35% ~ 44% in the molybdenum sulfide slag andWO₃ content is below 2%.

2. Through this method, the recovery rate of tungsten is approximately 88% and the recovery rate of molybdenum is 95%.