99.95% tungsten trioxide can be prepared by normal temperature extraction - normal temperature reextraction method to obtain ammonium paratungstate (APT) and then heat APT to a certain temperature for tungsten trioxide powder.
Producing Method
The wolframite is pressure boiled to obtain sodium tungstate solution. After pretreatment, extract active tungsten from the solution with organic reagents (various amines). That means purification and transformation effect are available. The obtained pure tungsten solution is treated by evaporative crystallization to get high-purity APT. Then, the APT is heated to a certain temperature to obtain the tungsten trioxide with purity higher than 99.95%.
Advantages of the above producing method to prepare WO3:
1. Advanced technology, easy operation, good reproducibility, and stable control of particle size.
2. Extraction rate and back extraction rate are greater than 99.9%.
3. Waste water and waste gas can be recycled, significantly reducing the "three wastes". Three wastes are waste water, waste gas and solid waste.
4. The production cycle is shortened by one-third, which greatly improves the production efficiency and reduces labor intensity. And therefore, the economic and social benefits are considerable.
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