Mineral formation process and environmental benefits of belite-ye'elimite cement clinker from industrial solid wastes

Abstract

To optimize resource utilization of bulk industrial solid waste and promote low-carbon production in the cement industry, the belite-ye'elimite cement (BSAC) clinker was prepared entirely from solid waste materials (carbide ash, coal gangue, steel slag, desulfurization gypsum). The mineral formation process of the clinker was systematically analyzed. Findings reveal that within the temperature range of 700-1100 °C, the clinker primarily comprises transition minerals such as aluminosilicate, aluminate, calcium sulphosilicate. At 1100-1200 °C, these phases gradually convert to dicalcium silicate (C2S) and ye'elimite (C4A3S). Above 1200 °C, changes in the minerals correlate to the structural and morphological evolution of C2S and C4A3S crystals. However, beyond 1320 °C, C2S exhibit an irregular morphology, and C4A3S decomposes. BSAC prepared at 1260 °C met the mechanical requirements for 52.5 grade sulphoaluminate cement. Environmentally, BSAC clinker reduces energy consumption by 18% and carbon emissions by 65% compared to traditional Portland cement.