Decomposition-carbonization of ammonium paratungstate in a fluidized bed

Abstract

In this study, the reduction-carbonization property of WO3 obtained by thermal decomposition of ammonium paratungstate (APT) under N2 and air atmosphere in a fluidized bed was investigated. The decomposition property of APT in N2 and air was analyzed by TG analyzer. Phase, morphology, deoxidation rate and carbonization rate of the decomposed products in the reduction-carbonization process were investigated. It was found that APT could be rapidly decomposed into monoclinic WO3 in a fluidized bed in N2 or air atmosphere. Compared with N2 atmosphere, air was more favorable for the rapid decomposition of APT and the crystal transition of WO3. Under the same conditions, the products obtained in N2 atmosphere had smaller grain size, larger porosity, faster deoxidation rate and carbonization rate. Both WO3 obtained in the N2 and air could be reduced and carbonized to nano-sized WC with SBET particle sizes of 63.70nm and 73.49nm in a fluidized bed, respectively.