Carbonate looping using MgO-based sorbents has recently aroused the scientific interest as an auspicious technology for intermediate temperature (200−400 °C) CO₂ capture, with the main hindrance being the slow sorption kinetics of MgO. This study investigated the preparation of MgO-based sorbents derived from mineral magnesite and promoted with a mixture of Li, Na and K nitrates, which by shifting into a molten state can reinforce the CO₂ capture kinetics. Mineral limestone was also tested as promoter, which enabled the formation of CaMg(CO₃)₂ as another carbonate product except MgCO₃. In-situ X-ray diffraction was employed to interpret the sorption mechanism of materials with different promoter contents and under various operating conditions. Even though CaMg(CO₃)₂ required a minimum temperature of 300 °C for formation in contrast to MgCO₃, it generally displayed a faster nucleation rate, which was profitable mainly when applying a low CaCO₃ to MgO molar ratio. However, the CaMg(CO₃)₂ decomposition demanded higher temperatures than MgCO₃, which were associated with more pronounced sintering of the sorbent and elevated energy requirements of the process. The increase of the alkali nitrate content led to a deterioration of the pore network, but also enabled a faster generation and growth of carbonate products. Lowering the CO₂ concentration of gas feedstock for more realistic carbonate looping applications required a slightly milder operating temperature for efficient CO₂ sorption to enhance both CO₂ solubility and carbonation kinetic driving force. The results proved the feasibility of mineral ores as sustainable low-cost precursors for intermediate-temperature CO₂ capture.

使用基于 MgO 的吸附剂的碳酸盐循环最近引起了科学兴趣，作为一种用于中温 (200-400 °C) CO ₂捕获的吉祥技术，主要障碍是 MgO 的缓慢吸附动力学。本研究调查了从菱镁矿中提取的 MgO 基吸附剂的制备，并用 Li、Na 和 K 硝酸盐的混合物促进，通过转变为熔融状态可以增强 CO ₂捕获动力学。还测试了矿物石灰石作为促进剂，其能够形成 CaMg(CO ₃ ) ₂作为除 MgCO ₃之外的另一种碳酸盐产物。原位X射线衍射被用来解释不同助剂含量和不同操作条件下材料的吸附机理。尽管与 MgCO ₃相比，CaMg(CO ₃ ) _{2 的形成}需要 300 °C 的最低温度，但它通常显示出更快的成核速率，这主要在应用低 CaCO ₃与 MgO 摩尔比时有利。然而，CaMg(CO ₃ ) ₂分解需要比 MgCO ₃更高的温度，这与更显着的吸附剂烧结和过程的能量需求增加有关。碱金属硝酸盐含量的增加导致孔隙网络的恶化，但也使碳酸盐产物的生成和生长更快。为更现实的碳酸盐循环应用降低气体原料的 CO ₂浓度需要稍微温和的操作温度以有效吸收CO ₂以提高 CO ₂溶解度和碳酸化动力学驱动力。结果证明了矿物矿石作为中温 CO ₂捕获的可持续低成本前体的可行性。