Ammonium Tungstate Solution Magnesium Carbonate Purification Phosphorus Removal

In practical applications, it was found that Na2WO4 solution could remove more than 90% of phosphorus by ion exchange without phosphorus removal by calcium salt, and the phosphorus concentration in the ammonium tungstate solution was also about 0-3 g/l. Therefore, calcium phosphorus removal has no substantial effect on phosphorus removal, and the process can be eliminated directly. In addition, the calcium salt removal process has many drawbacks, the content of phosphorus slag in WO3 up to 30%, production must be returned to the boiler alkali recycling, which consumes a lot of raw materials, production costs increased significantly.

ammonium tungstate solution magnesium carbonate purification phosphorus removal image

Therefore, some scholars believe that the use of magnesium salts instead of calcium salts can effectively remove the phosphorus contained in ammonium tungstate solution. Its brief process is as follows:

1. Before the ammonium tungstate solution is exposed to the magnesium salt, the first ammonium tungstate can be mixed with ammonium sulphide solution. By adding ammonium sulfide to the reaction system, the MoO42- in the solution can be vulcanized to MOS42- easily captured by Cu2+. By adding copper sulfate solution, other impurities such as molybdenum in ammonium tungstate solution can be effectively removed.


2. At room temperature, 300ml containing WO3 concentration of 230g/l and 0.22g/l containing ammonium phosphate in the 500ml beaker were added to the 500ml beaker, and the ammonium sulphate solution with volume of 1%-3.5% was added into the beaker, stirring evenly. Adding 1 to 1.4 times the theoretical amount of basic magnesium carbonate to the above mixture for deep phosphorus removal, the amount of magnesium salt with 1 times the theoretical amount is 0.2069g, the pH value of the reaction solution is =9-10, and the reaction time of phosphorus removal is 120min;

The results showed that under the sulfuration system, in the ammonium tungstate solution with high WO3 concentration and low phosphorus concentration, with the increase of the dosage of basic magnesium carbonate, the residual phosphorus concentration in solution decreased. When the theoretical multiplier of basic magnesium carbonate is 1 times, the phosphorus concentration in solution decreases from 0.22g/L to 0.012g/L, WO3 : P is 2.5 * 104, and phosphorus removal rate is 94.55%, which achieves the standard of dephosphorization.

The removal of phosphorus by magnesium carbonate combined the phosphorus removal process and sulfuration and impurity removal process to one step, which not only shortened the process flow, reduced the production cost, simplified operation, but also increased the production efficiency.