Properties of cement raw meals used as sorbents in a calcium looping process

Abstract

Calcium looping (CaL) is a promising carbon capture and storage (CCS) technology that has the potential to significantly reduce CO2 emissions in cement production. Integrating CaL with cement production provides a viable solution to the high CO2 emissions generated during the calcination process. This study examines the behavior of two industrial cement raw meals from different sites (A-RM and B-RM) under CaL conditions, focusing on phase composition, particle size distribution, and clinker phase evolution up to 1450 °C. Calcination and CaL experiments were conducted in a CO2-rich atmosphere, with materials characterized using quantitative X-ray diffraction (Q-XRD) and high-temperature X-ray diffraction (HT-XRD). The results showed that both raw meals absorbed similar amounts of CO2 during the cyclic CaL experiments. A-RM formed C2S and other silicates, while B-RM retained more free CaO due to a less effective reaction with coarser quartz (SiO2) particles. HT-XRD revealed delayed clinker-phase evolution in the 1000–1400 °C range in CaL-treated raw meals. However, CaL-treated raw meals achieved low free CaO at 1450 °C, suggesting that optimal kiln conditions can produce the desired phase composition. These findings indicate that integrating CaL-treated raw meals into cement production requires careful optimization of operational parameters to maintain clinker quality and minimize energy consumption. Further research should focus on improving the efficiency and reactivity of CaL-treated raw meals to enhance their suitability for industrial cement production.