Pre-reduction Kinetics of WO2.72 in a Fluidized Bed

In this paper, WO2 was obtained by the pre-reduction of WO2.72 under the mixture of CO-CO2-N2. The influence of some factors such as reduction potential (CO/(CO + CO2)), reaction temperature, and residence time on the pre-reduction of WO2.72 was investigated systematically; the kinetic equation of the pre-reduction process was also fitted. The results demonstrated that the reduction degree of WO2.72 was positively correlated with the reduction potential and reaction temperature. WO2.72 could be almost completely converted to WO2 when it was reacted at 950 °C for 60 min under a reduction potential of 0.9. The dynamic fitting results showed that the pre-reduction process satisfied the Avrami–Erofe′ev model with an average activation energy of 74.20 kJ/mol in the range of 850–950 °C. The relationships between the reduction degree and the reaction temperature, reduction potential, and residence time could be expressed as follows: x=1−(1−10.02374xCO−0.01683exp(−74.20T)t)3