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

• Calcium looping (CaL) impacts the reactivity and phase formation of cement raw meals. • CO 2 absorption is similar in different CaL-treated meals with varying CaO content. • Finer particles were consumed, and new silicate phases formed during CaL. • In-situ HT-XRD revealed delayed clinker phase formation in CaL-treated meals. • Optimizing kiln conditions is necessary when using CaL-treated raw meals. Calcium looping (CaL) is a promising carbon capture and storage (CCS) technology that has the potential to significantly reduce CO 2 emissions in cement production. Integrating CaL with cement production provides a viable solution to the high CO 2 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 CO 2 -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 CO 2 during the cyclic CaL experiments. A-RM formed C 2 S and other silicates, while B-RM retained more free CaO due to a less effective reaction with coarser quartz (SiO 2 ) 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.