在国家“双碳”目标背景下，如何减少煤炭行业的碳排放、实现碳封存已成为亟待解决的难题。煤炭行业作为高碳化石能源生产者和主体碳排放源提供者，在生产和消费过程中引发的大宗固废堆存、大型采空区形成和大量CO₂排放是制约煤炭可持续开发利用与绿色健康发展的瓶颈所在。为协同解决二氧化碳封存与矿山固废消纳问题，将大宗固废处置、固废高值化利用、CO₂封存、采空区利用有机结合，提出了二氧化碳充填的理念，从碳汇能力评估角度界定了二氧化碳充填的3种类型。具体开展工作包括：① 分析了CO₂充填料浆输运过程和矿化反应过程涉及到的基础理论，给出了各个过程的数学方程以及碳封存量计算公式，指出了温度、湿度等因素对矿化反应机理、碳封存量和充填体强度的影响规律。② 总结了现阶段CO₂矿化的工艺方法、主要碱性工业固废的CO₂封存能力和CO₂矿化强化措施。在此基础上提出了基于直接湿法矿化和间接矿化的2种CO₂充填材料制备工艺，满足矿井充填的流动性、凝固特性和强度要求。③ 针对CO₂充填过程中的CO₂物理封存问题，提出了窄条带式胶结充填和综采架后胶结充填2种技术路径，前者通过在弱充填条带中构筑多贯通孔隙的充填体CO₂物理封存，后者借助充填支架和链式自行充填挡板在长壁工作面采空区中间断构筑充填带，控制顶板垮落，形成CO₂物理化学封存空间。④ 为了评估CO₂充填的碳平衡效果，依据全生命周期法界定了CO₂充填中碳足迹及碳消纳的计算边界。然后，梳理了CO₂充填过程中的碳足迹及碳消纳，分别考虑了CO₂的来源、用量、损耗、转化等因素。给出了包括原料运输、充填料浆制备、井下注入与充填等过程中的碳足迹及碳消纳计算方法。研究成果有望降低CO₂封存的能耗及成本，对煤炭绿色开采及其可持续开发利用具有深远的意义。

Under the national “dual carbon” goal, how to reduce the carbon emissions of the coal industry and achieve carbon storage has become an urgent problem to be solved. The coal industry is the producer of high carbon fossil energy and the main carbon emission source provider. In the process of production and consumption, the accumulation of bulk solid waste, the formation of large goaf and a large amount of CO₂ emissions are the bottlenecks that restrict the sustainable development and utilization and the green and healthy development of the coal industry. In order to solve the problem of carbon dioxide storage and mine waste consumption, the bulk solid waste disposal, high-value solid waste utilization, CO₂ storage and goaf utilization were organically combined, the concept of carbon dioxide backfill was put forward, and three types of dioxide backfill were defined from the perspective of carbon sink capacity assessment. ① The basic theories involved in the transportation process of CO₂ filling slurry and mineralization reaction process are analyzed. The mathematical equations for each process and calculation formulas for carbon sequestration amount are provided. The influence of factors such as temperature and humidity on the mineralization reaction mechanism, carbon sequestration amount, and strength of the backfill body are pointed out. ② The carbonation technological approaches, CO₂ sequestration capacity of major alkaline industrial solid wastes and enhancing measures of CO₂ mineralization are summarized. On this premise, two types of CO₂ backfill materials preparation technique based on direct carbonationand or indirect carbonationand are presented, which can fulfill the criterion of mine backfill in fluidity, solidification characteristics and strength. ③ To solve the problem of decomposed CO₂ escaping during CO₂ backfill, two technical paths of strip roadway paste backfilling and intermittent backfilling behind packed hydraulic support have been proposed. The former sequesters decomposed CO₂ by constructing backfilling bodies with multiple through holes in the weak backfilling strip, while the latter uses packed hydraulic support and chain self-filling baffling to construct backfilling strips in longwall goaf to control roof caving and form a CO₂ physicochemical storage space. ④ In order to evaluate the carbon balance effect of CO₂ backfill, the calculation boundary of carbon footprint and carbon sequestration in CO₂ backfill was defined according to the life cycle method, including the stages of raw material mining, transportation, processing, injection, solidification, etc. Then, the carbon footprint and carbon sequestration in the CO₂ backfill process were sorted out, and factors such as the source, dosage, loss, and conversion of CO₂ were considered. Next, the calculation methods of carbon footprint and carbon sequestration in the processes of raw material transportation, filling slurry preparation, underground injection and filling were given. The research results are expected to reduce the energy consumption and cost of CO₂ storage, and have far-reaching significance for green coal mining and sustainable development and utilization.