The research of effect of carbon powder

ferrosilicon (75% Si) powder and silicon carbide powder on scheelite (67. 25% W03) powder reduction kinetics has been carried out by 15 kW carbon tube furnace in laboratory. The results showed that scheelite reduced by carbon was second order reaction and the apparent activation energy was 234. 6 kj/mol; the reactivity of carbon was poor at low temperature

but its reaction rate increased obviously at temperature up to 1 400 ℃. The reactivity of ferrosilicon was steady with increasing temperature

and reaction product was SiO

2

to increase slag amount. The reactivity o£ silicon carbide was good at temperature N1 400 ℃. Carbon and ferrosilicon are available for low alloying ratio (3%W) and silicon carbide is suitable for higher alloying ratio (N5%W).