Rapid carbothermal reduction

Only recently was a new caibothermal reduction process developed in which the WC is synthesized by a rapid carbothermal reduction of tungsten oxides in a vertical graphite transport reactor (RCR entrainment process) [3.49]. Rapid heating of the WO3/C mixture driven by thermal radiation allows conversion of the mixture into a carbide precursor (WCi. c) within very short reaction times (a matter of seconds). In a second step, additional carbon is added to the carbide precursor to form a mixture, which then imdergoes a second heat treatment to convert the precursor into substantially pure WC. 

The Rapid Carbothermal Reduction (RCR) Process (The Dow Chemical Company) [9.19,9.20], In principle, the patented RCR process is another type of direct carburization. The tungsten carbide powder is continuously synthesized by an extremely rapid carbothermal reduction of WO3 in a graphite transport reactor. Calculated heating rates are in the range of 100 million K per second by thermal radiation. The WO3/C mixture during this process is converted to a tungsten carbide precursor (WCi c) within seconds. 

H Maeda, T Yoshikawa, K Kusakabe, S Morooka. Synthesis of ultrafine NbB2 powder by rapid carbothermal reduction in a vertical tubular reactor. J Alloys Compos 215 127, 1994. 

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