Microstructure and Thermal Properties of Water-Cooled Copper Slag with Different Particle Sizes

Copper slag is a solid waste produced in the process of smelting copper, which contains a large number of available resources. In order to separate and extract iron and other valuable components from copper slag, the effects of particle size of copper slag on phase composition and metallographic structure were studied by chemical analysis, X-ray diffraction, metallographic and thermogravimetric methods. The results show that copper slag contains more Fe2O3 and TiO2, and the harmful impurities have higher S content and good fluidity. The particle size is mostly distributed between 0.425 mm and 4 mm. In the copper slag, fayalite (Fe2SiO4), hematite (Fe2O3), magnetite (Fe3O4) and amorphous gangue glass were present. As the calcination temperature increases, the fayalite in the copper slag is oxidized to hematite and amorphous silica, followed by the transformation of the crystal form of magnetite (Fe3O4→ γ-Fe2O3→ α-Fe2O3).