Ultrafine or nano-sized of tungsten carbide (WC) is the key material to prepare ultrafine grained cemented carbides. In this paper

nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide (WO

2.72

) as the raw material

a fluidized bed as the reactor

and CO as the carbonization gas. The relationship between particle sizes and reaction temperatures

residence times

atmospheres has been investigated systematically. In addition

the physical-chemical indexes (such as residual oxygen

total carbon and free carbon) of the products were measured. The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950 ℃. As the residence time increased

the particle size decreased gradually

and then increased due to slight sintering. The introduction of hydrogen reduced the carbonization rate

and is not beneficial to obtaining nano-sized WC. Products that satisfy the standard were obtained when WO

2.72

reacted with CO at 850 ℃

900 ℃ and 950 ℃ for 3.0 h

2.5 h and 2.0 h

respectively. The particle sizes of the three samples calculated from the specific surface area were 46.4 nm

53.2 nm and 52.1 nm

respectively.