Prepare Phosphato-Tungstic Acid from Ammonium Paratungstate

A method for preparing phosphato-tungstic acid by using ammonium paratungstate as raw material is proposed in this paper. The principle is: ammonium paratungstate reacts with inorganic acid to get a reactive acid precipitation, and then contacts with phosphoric acid to obtain phosphato-tungstic acid solution, crystallize and we get phosphato-tungstic acid crystal.



Specific steps are as follows:
1. Ammonium paratungstate reacts with inorganic acid to get a reactive acid precipitation;
Inorganic acid can be hydrochloric, sulfuric, nitric or hydrochloric acid, sulfuric acid and nitric acid can mix at any volume ratio, the appropriate concentration of 0.2 mol/L~6.0mol/L; the amount is optional, as long as active precipitation of phosphato-tungstic acid is able to generated; the reasonable temperature is10 ~ 40℃; reaction time for 2~5 hours;
2. Active precipitation of phosphato-tungstic acid reacts with excessive phosphoric acid solution, and get phosphato-tungstic acid solution;
3. Precipitate phosphate acid from the solution, drying and crystallizing to get the crystal.