Abstract

In the present study, the focus is on the analysis of carbothermal reduction of oxide powder prepared from waste WC/Co hardmetal by solid carbon under a stream of argon for the recycling of the WC/Co hard-metal. The oxide powder was prepared by the combination of the oxidation and crushing processes using the waste WC-8 wt.%Co hardmetal as the raw material. This oxide powder was mixed with carbon black, and then this mixture was carbothermally reduced under a flowing argon atmosphere. The changes in the phase structure and gases discharge of the mixture during carbothermal reduction was analysed using XRD and gas analyzer. The oxide powder prepared from waste WC-8wt.%Co hardmetal has a mixture of WO_3 and CoWO_4. This oxide powder reduced at about 850°C, formed tungsten carbides at about 950°C, and then fully transformed to a mixed state of tungsten carbide (WC) and cobalt at about 1100°C by solid carbon under a stream of argon. The WC/Co composite powder synthesized at 1000°C for 6 hours from oxide powder of waste WC-8wt.%Co hardmetal has an average particle size of 0.3 µm.

• Keywords: Hardmetal;Tungsten carbide;Carbothermal reduction;Recycling;