Preparation and dynamics of silicate based sintered materials using high content solid waste

In this paper, steel slag and fly ash as the main raw materials, silicate-based sintering materials (SBSM) were prepared by using high-temperature firing method. The effects of steel slag addition and firing temperature on the linear shrinkage, water absorption, bulk density, and compressive strength parameters of SBSM were studied. The results show that with the increase of steel slag addition and firing temperature, the water absorption rates of SBSM show a trend of first decreasing and then increasing; the volume density, shrinkage rate, and compressive strength show a trend of first increasing and then decreasing. The main phase of SBSM is anorthite; however, a higher amount of steel slag and higher firing temperature can promote the formation of pyroxene phase. The microstructure composed of anorthite, pyroxene, and glass phases is similar to that of "reinforced concrete," which is more conducive to improving the strength and toughness of the SBSM. By calculating the crystallization activation energy and crystal index, a crystal activation energy of 50.72 kJ/mol is obtained, which is helpful for crystal formation. The crystal index is 1.22, indicating that the crystallization mode in the SBSM is surface crystallization.