Reduction of tungsten oxides with carbon. Part 1: Thermal analyses

摘要: The kinetics and mechanism of the reduction WO3 with carbon (in form graphite lamp black) were studied using isothermal thermogravimetry small sample masses (< 50 mg) in temperature range 935 to 1100°C. Two stages observed reduction. first stage corresponds approximately formation WO2 final product was tungsten. COCO2 ratio gaseous products had a considerable influence on reactions occurring. The rate under conditions could be described by diffusion models, is proposed involve CO(g) CO2(g) through pores reacting tungsten oxides. activation energies black systems differed significantly for this (386 compared 465 kJ mol−1). These are high process may inflated changes structure equilibrium as increases. second reaction can first-order equation, it that limited dioxide, rather than oxide. measured energy 438 mol−1 slightly higher reported values carbon-carbon dioxide (up 400