Coarse blue tungsten oxide’s main raw material is ammonium paratungstate (APT). APT is a white crystal. The production process of ammonium paratungstate varies. It depends on the type of tungsten concentrate used and the impurity contained.
Several Kinds of Production Processes of Ammonium Paratungstate
1. Soda boiling black tungsten concentrate (caustic soda) at high pressure - ion exchange - evaporation crystallization;
2. Soda boiling black tungsten concentrate (caustic soda) at high pressure - solvent extraction - evaporation crystallization;
3. Pressure boiling scheelite concentrate with soda - ion exchange - evaporation crystallization;
4. Pressure boiling scheelite concentrate with soda - solvent extraction - evaporation crystallization;
5. Pressure boiling scheelite concentrate with caustic soda and villiaumite - ion exchange - evaporation crystallization;
6. Pressure boiling scheelite concentrate with caustic soda and villiaumite - solvent extraction - evaporation crystallization;
7. Decomposing scheelite concentrate with hydrochloric acid - ammonia neutralization - evaporation crystallization.
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