Synthesis and Characterization of Cement Clinker Using Waste Glass and Oyster Shells as Natural Ore Substitutes

This study investigates the process of synthesizing eco-cement clinker using recycled powdered glass (RPG) and oyster shell residue (OSHL) as primary raw materials. Analysis of the mineral composition of RPG revealed that it primarily consists of silica and contains a high level of alkali metal oxides, while OSHL comprises a high-purity trigonal calcite structure, similar in chemical composition to limestone. Comparative analysis of the synthesized ecological cement and its hydration products showed that, after heat treatment at 1200 °C, the alkali metal content in the H12 sample significantly decreased, thereby meeting the standards for cement raw materials. The hydration process of RPG and OSHL ecological cement (ROEC) exhibited greater reactivity, with the presence of alkali ions (such as Na⁺ and K⁺) accelerating the cement hydration reaction and significantly enhancing early strength. Furthermore, as the curing time increased, the hydration products of ROEC became more uniform, ultimately consisting primarily of calcite. These findings indicate that the combination of RPG and OSHL offers a novel approach to cement synthesis, while reducing the content of alkali metal oxides, thereby aligning the cement clinker more closely with modern production standards.