硅酸盐学报2025，Vol.53Issue(5)：1258-1268,11.DOI:10.14062/j.issn.0454-5648.20240599
电石渣捕集水泥窑烟气中的CO2及吸收效率改性研究进展
Research Progress on CO2 Capture in Cement Kiln Flue Gas and Modification of Absorption Efficiency of Calcium Carbide Slag
摘要
Abstract
Carbon dioxide emissions from cement kiln flue gas constitute a significant contributor to global climate change and environmental pollution.As global emission reduction targets progress,research and application of carbon capture,utilization,and storage(CCUS)technologies have increasingly become critical strategies for mitigating CO2 emissions.Among these technologies,the calcium cycle method demonstrates substantial potential due to its low cost,high efficiency in CO2 trapping,and broad applicability,particularly in the context of cement kiln flue gas.However,traditional calcium-based materials,such as limestone,face challenges including high precalcination temperatures and resource wastage,highlighting the need for more efficient and sustainable alternatives. Calcium carbide slag,an industrial by-product,has shown significant promise as a material for the calcium cycle method.It contains a high proportion of reactive CaO3 along with inert components such as alumina and magnesium oxide.These inert components enhance resistance to sintering after preburning.However,repeated use of calcium carbide slag leads to pore structure collapse,particle agglomeration,and sintering,severely diminishing its adsorption performance and posing a significant barrier to practical application. To address these challenges,various modification techniques have been explored to improve the absorption efficiency and sintering properties of calcium carbide slag,as well as to mitigate the impact of SO2 and NOx in flue gas on CO2 absorption. Organic acid modification has been identified as an effective strategy to enhance the adsorption performance of calcium carbide slag.Through reactions with calcium hydroxide to form organic calcium salts,pyrolysis at high temperatures releases small molecules that disrupt the original structure of the slag.This process increases porosity,specific surface area,and CO2 adsorption capacity.Different organic acids,due to their distinct molecular structures,yield variations in the molecular weight of organic calcium salts and the types and quantities of small molecules released during pyrolysis.Consequently,modifying calcium carbide slag with specific organic acids allows tailoring of its pore structure to enhance CO2 adsorption performance. Doping modification technology is another effective approach.By incorporating various substances into the slag,the properties of calcium carbide slag can be optimized through different chemical reaction mechanisms.Inert materials serve as structural frameworks,inhibiting CaO grain migration and growth to improve anti-sintering performance.Doping with oxygen-deficient materials facilitates CO2 diffusion and O2- migration,while potassium and sodium salts increase defect concentrations in the CaCO3product layer,enabling more efficient Ca2+ migration and enhanced CO2 absorption. Hydration processes also play a critical role in influencing sintering.While CaCO3 typically decomposes at high temperatures,introducing water vapor during calcination reduces the partial pressure of CO2,promoting its conversion to CaO.Water vapor also shortens decomposition residence time and slows sintering,delaying sintering deactivation and improving stability.By optimizing calcination temperatures and water vapor concentrations,the CO2 adsorption performance and stability of calcium carbide slag can be enhanced over multiple cycles. In the context of cement kiln flue gas treatment,SO2 and NOx pose additional challenges to the CO2 trapping performance of calcium carbide slag.SO2,being strongly acidic,preferentially reacts with CaO to form dense CaSO4 layers,which accumulate over cycles,diminishing adsorbent activity.Research suggests that specific modification methods or adjustments in the absorption sequence(e.g.,absorbing CO2 before SO2)can mitigate these effects.Regarding NOx,calcium carbide slag inherently lacks reductive properties and cannot remove NOx through traditional calcium cycle methods.Doping with reducing substances,such as copper,iron,and other metal oxides,can enable NOx reduction by promoting reactions that convert NOx into harmless nitrogen and oxygen. Summary and prospects The future of calcium carbide slag modification technology is expected to move towards systematic and refined strategies.These strategies can leverage the synergistic effects of multiple modification techniques to optimize performance across different reaction stages.As research progresses,the multifaceted applications of calcium carbide slag will gain increasing recognition.Beyond its role in CO2 capture,it holds significant potential for processes such as desulfurization and nitrogen removal. From an environmental perspective,utilizing calcium carbide slag addresses resource wastage while aiding the cement industry in achieving a green transformation by reducing greenhouse gases and pollutants such as CO2,SO2,and NOx.Continuous innovation in modification technology will ensure that calcium carbide slag not only plays a pivotal role in CO2 capture but also in mitigating pollutants,contributing to the attainment of global emission reduction goals.The enhanced versatility and cyclic stability of modified calcium carbide slag will further support the green transition of the cement industry and other high-emission sectors,contributing to efforts toward a sustainable future.关键词
电石渣/钙基吸收剂/二氧化碳/吸收效率Key words
carbide slag/calcium-based absorbents/carbon dioxide/absorption efficiency分类
资源环境引用本文复制引用
王亚丽,陈泽升,崔素萍,杨金龙,裴天蕊..电石渣捕集水泥窑烟气中的CO2及吸收效率改性研究进展[J].硅酸盐学报,2025,53(5):1258-1268,11.基金项目
国家自然科学基金(52072009). （52072009）
