The reaction of the carbon reduction of WO3 in a nitrogen atmosphere was studied fundamentally.
The results obtained are as follows:
1) Sublimination of WO3 was observed at high temperatures over 1200°C and its decomposition occurred simultaneously when the atmosphere had a low oxygen potential.
2) The carbon reduction of WO3 is proceeded by the thermal decomposition of WO3 as well as the reaction with carbon at the starting stage of reaction.
3) It was noted in small samples that the carbon reduction was induced after WO3 had been changed to W18O49 of needle-like crystal between 800°C and 1000°C.
4) On an industrial scale, the reaction is more complex due to the effect of the great quantity of product gas and heat supply. For this purpose, a new type of furnace is needed.