Industrial grade blue tungsten oxide is a blue powder with an average particle size of less than 100nm and purity higher than 99.95%.
Industrial Production of Blue Tungsten Oxide
The producing method of blue tungsten oxide in industry is generally using a four tube muffle furnace or a rotary electric furnace to calcine ammonium paratungstate (APT) at a temperature range of 600~900°C under a protective atmosphere (hydrogen gas) or in an airtight condition. The main control point of quality for this process is calcination.
This process is mainly to calcinate APT at high temperature to obtain BTO in the four tube muffle furnace under the protective atmosphere, which is mainly controlling the oxygen index (O/W) and grain size of blue tungsten oxide. The grain size of ammonium paratungstate, calcination temperature, feed rate, calcination atmosphere and calcination time have a certain influence on the two quality indicators, oxygen index and grain size.
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