Effect of Fe2O3 on the crystallization behavior, microstructure and properties of glass-ceramics prepared from the modified tailings after reduction of copper slag

Abstract

The modified tailings containing Fe2O3 after reduction of copper slag were used as the raw materials for the preparation of gehlenite-based glass-ceramics. The effect of Fe2O3 content on the crystallization behavior, microstructure and mechanical properties of glass-ceramics were investigated by Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS). The results show that when the Fe2O3 content increases from 0 wt% to 4 wt%, the crystallization peak temperature of base glass decreases and the crystallization activation energy of base glass decreases firstly and then increases. The minimum crystallization activation energy is 237.71 kJ/mol when the Fe2O3 content in base glass is 1 wt%, resulting from the highest content of glass modifier [FeO6]-octahedral in the glass. The crystallization index indicates that the crystallization method of base glass is surface crystallization, irrespective of the Fe2O3 contents of the base glass. Although the crystallization rate is slow resulting from the limited crystallization sites provided by Fe2O3, the glass-ceramics with 2 wt% Fe2O3 has a good comprehensive performance. When the nucleation process is at 850 ℃ for 120 min and the crystallization process is at 980 ℃ for 120 min, the flexural strength, microhardness, volume density and water absorption of the glass-ceramics with 2 wt% Fe2O3 are 138.26 MPa, 872.19 HV, 2.81 g/cm3 and 0.16%, respectively.