Production of High-Strength Glass-Ceramics from Industrial Wastes Using Phase Equilibrium Diagram of CaO-Al2O2-SiO2 System

Abstract

The production of new materials by mixing together more than two raw materials is a useful method from the viewpoint of waste disposal. However, a number of trials and errors are required to produce the desired material. It is therefore important to clarify the target to improve the efficiency of production. In this study, as targets of production, glass-ceramics with anorthite, wollastonite, and gehelenite crystals are used, and inorganic wastes of fly ash, concrete sludge, and glass cullet are used as raw materials. The mixing ratios of these inorganic wastes are determined on the basis of the phase equilibrium diagram of CaO-Al2O3-SiO2. The XRD profiles and SEM observations showed that the crystallized phase of the glass ceramic samples produced were identified as anorthite, wollastonite, and gehelenite, respectively. Moreover, the strength, hardness, Young's modulus, fracture toughness, and acid resistance were measured. From the results, it is considered that glass-ceramics with wollastonite crystals are excellent in terms of mechanical properties, but those with anorthite are excellent in terms of chemical resistance.