Effects of the Inert Materials on the Stability of Ca-Based CO2 Sorbents and the Synergy with Cement Manufacture

The sintering deactivation of CaO sorbents limits the commercialization and application of calcium looping. Improving resistance to sintering and the synergy with cement manufacture are two effective paths to reduce the cost of this CO2 capture technology. In this work, a series of Ca-based sorbents stabilized with six kinds of spacers was prepared by freeze drying. The multicycle CO2 capture tests under the severe conditions (carbonation in 15 vol % CO2 at 650 degrees C for 10 min and calcination in 15 vol % CO2 at 900 degrees C with no dwell time) indicated that the sorbents stabilized with Y2O3, CaZrO3, and MgO showed superior sintering-resistant ability. The stabilization mechanism was explored via material characterization techniques, including X-ray diffraction, N-2 physisorption, and scanning electron microscopy. The sorbent stabilized with CaZrO3 was chosen to incorporate into the cement raw meals to prepare the cement clinker samples. It was found that the moderate introduction of CaZrO3 had little impact on the 3CaO center dot SiO2 (tricalcium silicate, providing the early compressive strength of cement) generation in the cement clinkers, which first proved the feasibility of preparing the qualified cements by use of calcium sorbents stabilized with the specific spacer.