Effect of SiO2/MgO ratio on the properties of diopside-based ceramics

Abstract

Diopside-based ceramics were successfully synthesized by utilizing recovered extracted titanium slag, asbestos tailings, and quartz tailings as raw materials. The objective of this approach is to explore novel sources of raw materials for ceramic production and optimize the utilization of industrial solid waste. The effects of SiO2/MgO mass ratio (S/M) on the properties of the ceramics were studied by investigating the bulk density, bending strength, water absorption and corrosion resistance. The microstructure and crystallization process of the ceramics were analyzed by SEM-EDS and XRD. The results revealed that the increase of S/M is beneficial to the formation of low viscosity liquid phase, the promotion of ion migration and crystallization process, the decrease of sintering temperature, the decrease of water absorption and the increase of bulk density and bending strength of ceramics. In addition, the increase of S/M helps to increase the acid resistance of ceramics. The most optimal parameters (bulk density of 2.97 g·m−3, bending strength of 118.73 MPa, water absorption of 0.29 %, and acid resistance of 98.98 %, respectively) were achieved at the S/M of 2.50 and the sintering temperature of 1175 °C. The increase of S/M ratio also affects the phase reconstruction process. At lower S/M (1.75–2.08), Melilite is transformed into diopside, and at higher S/M (2.50–4.71), Melilite is transformed into diopside and anorthite. The present study aims to optimize the utilization of industrial solid waste (100 %), which not only protects the environment, but also provides a novel approach for resource recovery from such wastes.