Fabrication of Tungsten Powder Mixtures with Nano and Micro Size by Reduction of Tungsten Oxides

Kinetics of nonisothermal reduction and carburization of WO3─NiO nano‐composite powders by CO─CO2

“…The average E a value for Step 4 is 196.9 kJ/mol. In general, the activation energies obtained for the different reaction steps here are significantly different from those reported in earlier studies, 5,7,8,10,21,22 which is likely due to the difference of thermal treatment type, for example, nonisothermal versus isothermal, respectively, the type of reducing agent such as H 2 and CH 4 for the previous studies, and the properties of the raw material: particle size, chemical composition, and homogeneity. These factors as discussed above can considerably change the calculated apparent activation.…”

“…Kwon et al . estimated the activation energy of WO 3 reduction by H 2 based on the slope of the Kissinger method and reported 117.4 and 94.6 kJ/mol for the reductions of WO 3 to WO 2 and WO 2 to W, respectively.…”

“…Kwon et al 22 estimated the activation energy of WO 3 reduction by H 2 based on the slope of the Kissinger method and reported 117.4 and 94.6 kJ/mol for the reductions of WO 3 to WO 2 and WO 2 to W, respectively. In another study on hydrogen reduction of tungsten oxides, the apparent activation energy for reduction of WO 3 to WO 2 and WO 2 to W (for raw material of nano size CuO-WO 3 composite powder) was 101 and 156 kJ/mol, respectively.…”

Fabrication of tungsten oxide powder from WC–Co cemented carbide scraps by oxidation behaviour

“…Thus, particle and phase control of the powder are important factors. To produce high-quality cemented carbide powder in a resource-efficient manner, it is necessary to develop a process that enables the efficient and complete oxidation of cemented carbide scrap [1,[7][8][9][10][11][12].…”