Preparation of ultrafine tungsten powder by fluidized bed hydrogen reduction of WO3-Co3O4

This article investigated the preparation of ultrafine W powder by fluidized bed hydrogen reduction, and the apparent activation energy was determined for various reduction stages by using temperature programmed reduction with hydrogen. The results demonstrate that the introduction of Co 3 O 4 significantly enhances the reduction process of WO 3 .High Co 3 O 4 content can lead to the formation of CoWO 4 in the initial stage and obtain products with high content of Co 3 W. An increase in the Co 3 O 4 content correlates with a gradual decrease in the particle size of the product. The apparent activation energy for the WO 3  → WO 2 and WO 2  → W processes decreases as the Co 3 O 4 content increases. It can be decreased from 105.59 kJ /mol to 78.72 kJ/mol for the WO 3  → WO 2 stage, and from 107.38 kJ/mol to 78.38 kJ/mol for the WO 2  → W stage, respectively.