Utilization of Low-Grade Limestone and Solid Waste for the Preparation of High-Belite Portland Cement.

Abstract

In this study, high-belite Portland cement clinker was successfully prepared by using low-grade limestone and solid-waste calcium carbide slag and steel slag, achieving resource utilization while reducing CO₂ emissions caused by raw materials decomposition in the cement industry. Using X-ray diffraction, microscopic images, thermogravimetric analysis, and differential scanning calorimetry, the physicochemical reaction process, phase composition, and microscopy of clinker were studied. The results indicated that the high-belite Portland cement clinker can be successfully produced at 1340 °C for 1 h with a belite content of 58.6% and an alite content of 24.2% when the composition of raw material was suitable. Meanwhile, the content of high-reactive-phase α-C₂S can reach 1.4%. Via microscopic viewing, C₂S and C₃S were interphase distributed and well developed. In this study, the CO₂ emission of the prepared high-belite Portland cement clinker was 54.67% lower than that of ordinary Portland cement clinker. All the above results confirm that high-belite Portland cement clinker can be produced using low-grade limestone and solid wastes, which can significantly reduce CO₂ emission during Portland clinker production and promote an innovative approach to the cement industry.