Doping ammonium metatungstate may be applied as a raw material for producing tungsten products with special ding. For example, potassium doped ammonium metatungstate may be used to prepare K-doped tungsten powder, which can be used for preparing tungsten filaments.
Generally, doping AMT is referred as to white crystalline powder obtained by doping other elements in AMT in the liquid phase process.
Nano Grain Size Tungsten Powder Prepared by Arsenic-doped Ammonium Metatungstate
1. AMT is added to nitric acid solution with simple arsenic. The content of arsenic in the raw material is 0.1~5wt%;
2. After stirring uniformly, dry, and arsenic-doped precursor composite powder is obtained after grinding;
3. The composite powder is added in a chamber type electric resistance furnace, calcined in an air atmosphere at 580-620°C, and incubated for 2 to 3 hours to obtain tungsten trioxide powder.
4. Tungsten trioxide powder is placed in a tube-type furnace and reduced under hydrogen. The temperature is raised at the rate of 5°C/min, the reduction temperature is 780 to 820°C, and the temperature is kept for 3~4 hours to prepare nano tungsten powder.
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