Blue Tungsten Oxide Cyclic Oxidation Producing Tungsten Powder

Fine tungsten powder is an important raw material for producing tungsten carbide powder, to improve the performance of carbide tungsten is necessary to reduce or eliminate the coarse tungsten powder particles. Otherwise it will cause tungsten carbide cracks, fracture and other phenomena in the course. After studies the process of using blue tungsten oxide as raw material to produce fine tungsten powder research found that by using exceptionally pure ammonium paratungstate calcinate in ammonia to get blue tungsten and then go through the cyclic oxidation producing fine tungsten powder, and the tungsten powder properties is better which is less coarse. Producing process as follows:

1. Slow heating exceptionally pure ammonium paratungstate which is in ammonia to 600 ℃, when the temperature reach 600℃for 10min heat preservation to produce  blue tungsten oxide.
2. To obtain tungsten powder by restoring blue tungsten oxide in hydrogen.
3. The obtained tungsten powder slowly heating in air to 500 ℃, for the first time oxidation. When the temperature reaches 500 ℃ for 10min heating preservation to obtain tungsten trioxide.
4. The obtained tungsten trioxide in the hydrogen condition to process second reduction.