REDUCTIOIN OF TUNGSTEN OXIDES BY CARBON OR CARBON-CONTAIMNG COMPOIJNDS - 4

Carbothermic reduction of WO₃ 0r ore concentrates is of technical importance in melting metallurgy-preparation of ferrotungsten, melting base, and cast carbide.

The reduction of WO3 by carbon in the solid state, however, has gained technical interest and importance m the case when the desired final product is tungsten carbide. This process is named “Direct Carburization” and the basic reaction is described by the following equation:

   WO₃+4C→WC+3CO

In contrast to the conventional procedure for WC production-W03 reduction by hydrogen followed by W+ C mixing and carburization-this method allows the formation of WC in only one step, while, carbon acts as carburizing and as reducing agent.

The above equation is only of theoretical value because, besides the main reaction, the following reactions also occur:

WO₃+5/2C→WC+3/2CO₂

C+CO₂→2CO

Consequently, in this procedure, an uncertainty in the carbon demand is given. This means that, depending on the operating conditions, the carbon content of the final product may vary significantly.

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