Effect of heating rate on the sinterability, crystallization, and mechanical properties of sintered glass-ceramics from granite waste

摘要

Huge amounts of granite wastes have been generated in the granite-processing industry and should be properly disposed to reduce the negative impacts on the environment and health care. In this work, waste granite powder was modified and sintered to prepare high-strength and tough glass-ceramics. The heating rate was studied to clarify its effects on the sinterability, crystallization, and mechanical properties of glass-ceramics. With the increase in heating rate, the densification of sintered glass-ceramics was promoted by the liquid glassy phase from the microcline phase. The glass-ceramics were strengthened and toughened simultaneously due to the improved densification and increased crystallinity. The toughening mechanism was attributed to the crack bridging, deflection, and branching. The maximum flexural strength of 143MPa and fracture toughness of 2.1MPam(1/2) were achieved with a heating rate of 50 degrees Cmin(-1), far superior to that of natural granite. The crystal structure of sintered glass-ceramics indicated the main crystalline phase of anorthite. These glass-ceramics with excellent mechanical properties promise the practical reutilization of granite wastes in the construction tiles.