Ammonium tungstate is a kind of white rhombic crystal, which is soluble in water and insoluble in ethanol. Its chemical formula is (NH4)10W12O41~xH2O. And It loses four molecular of crystal water at the temperature of 100℃. At the temperature of 20°C, its solubility in water is less than 2%.
Ammonium tungstate is one of tungsten compounds and is an important intermediate material for tungsten metallurgy industry. It is an important raw material for producing ammonium paratungstate, ammonium metatungstate and phosphorus tungstate. And it can be applied to produce ammonium tungstophosphate (AWP). Also, it can be used for producing tungsten products.
Producing Method - Neutralization Method
1. Alkali decomposition of tungsten concentrate:
MnWO4 ? FeWO4 + 4NaOH → 2Na2WO4 + Fe (OH) 2 ? Mn (OH) 2
2. React with calcium chloride to synthesize calcium tungstate:
Na2WO4 + CaCl2 → CaWO4 + 2NaCl
3. Acidity decomposition of calcium tungstate:
CaWO4 + 2HCl → CaCl2 + H2WO4
4. React with ammonia solution:
12H2WO4 + 10NH4OH → 5 (NH4) 2O ? 12WO3 ? 5H2O + 12H2O
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