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

ABSTRACT Tungsten contains cemented carbide and is an industrially important material. Tungsten oxide is also used as a hardmetal; thus, there is an increased demand for nanosized and highly purified products. This has spurred considerable research interest toward developing a controlled technique for oxidising cemented carbide scraps to directly recycle them into powders. Cemented carbide is converted into tungsten oxide in an oxidising atmosphere, and is characterised as a porous powder formed by expansion during the oxidation reaction. Uniformly oxidising powdery cemented carbide during oxidation heat treatment is difficult, and tungsten oxide particles grow when oxidised at a high temperature for long durations. To study the uniform oxidation of WC–Co cemented carbide, the oxidation behaviour of powdered WC–Co was analysed by varying the temperature and atmospheric oxygen concentration. The phases of the produced oxide powder were analysed, and the specific surface area was measured to confirm the average particle size.