WC powder was prepared by the combination of
spray-drying and fixed bed technology.The effects of the spray-drying process
of the
ammonium paratungstate and the carburization
temperature on the formation of the precusor and WC powder were investigated.The results show that the precursor powder is homogeneous and spherical with an average diameter of 10～20 μm.The spray-drying temperature has no obvious influence on the size and distribution of the precursor particles.The composition of the powder spray-dried at 400℃ is the same as that of the ammonium paratungstate,indicating that no decomposition reaction occurs.The diameter of the WC powder prepared by carbonizing the precursor with H_2/CO at 900℃ is about 0.5～2.0 μm with a specific surface area of 6.5 m~2/g.Compared to the traditional preparation methods,the spray-drying and fixed bed technology decreases the preparation temperature and the WC powder as-produced has higher specific surface area.It is suited to be used as catalyst in hydrogenation,reforming,cracking reactions etc.