Reduction mechanism of WO3 + CuO mixture by combined Mg/C reducer

Abstract

The mechanism and kinetics of tungsten and copper oxides joint reduction by Mg + C combined reducer was studied at high heating rates by thermal analysis method utilizing high-speed temperature scanner. The effective values of activation energy for magnesiothermic reduction stage for the binary (WO3–Mg, CuO–Mg), ternary (WO3–Mg–C, CuO–Mg–C, WO3–CuO–Mg) and quaternary (WO3–CuO–Mg–C) systems were determined in a new and wide range of heating rates (Vh = 100–5200 °C min−1). It was shown that for all the systems under study the increasing of heating rate shifts T* values toward to high-temperature area and unlike the low heating rates (Vh = 5–20 °C min−1, DTA/DTG studies) at high heating rates Mg always participates in molten state. In addition, by varying heating rates of reagents it was possible to separate the main stages and analyze intermediate compounds, making useful tool for the exploration of interaction mechanism in the complex systems. On the other hand, the tendency of merging of metals reduction stages at higher heating rates has an essential practical interest. That is, simultaneous reduction in metals is very prominent for obtaining metal composites with more homogeneous microstructure.