Effect of Carbon Content on Mechanoreduction of Copper Oxide

The reduction of CuO with different amount of carbon (CuO:C=2:1, 2:1.5, and 2:2, in molar ratio) induced by ball milling is examined by x-ray diffraction and transmission electron microscopy. It is found that reduction process is closely related to the carbon content. CuO can be completely converted into Cu if an excessive C is used (i.e., C = 1.5 or 2.0mol). However, the reduction of CuO follows a two-step process, CuO→Cu→Cu₂O, if the mixture only contains a nominal C content (i.e., C = 1 mol). A tentative model in terms of solid state reaction at the interfaces is proposed to explain the effect of carbon content on the mechanoreduction of CuO.