In situ XRD study on function mechanism of pyroxene and anorthite in Si-Ca ceramics from ferronickel slag

Abstract To investigate the densification mechanism of ceramics from Ca-Mg-Fe containing solid waste, excluding Na's effect on anorthite, pyroxene and anorthite in Si-Ca ceramics are derived from ferronickel slag was studied using two batches of typical ceramics. The sintering and mechanical properties were investigated, and the modifications in the crystal structure were investigated using X-ray diffractometry (XRD), especially with in situ XRD. Results showed that anorthite just formed the skeleton phase, whereas pyroxene acted as a flux to reduce the optimal sintering temperature of ceramics by about 40 °C. The property of pyroxene itself, not the densification, mainly contributed to the high bending strength (119.30 MPa) for Si-Ca ceramics. Additionally, a fast cooling rate was beneficial to precipitate pyroxene during the sintering process. Therefore, this work could provide a theoretical basis for utilizing industrial solid wastes containing ferronickel slag in Si-Ca ceramics.