The wettability of room temperature ionic liquids (ILs) on coal structure was studied by measuring contact angle, water-retaining property, and FTIR spectra. The eight ILs utilized were [EMIm][BF₄], [EMIm][NTf₂], [PMIm][BF₄], [BMIm][BF₄], [HOEtMIm][BF₄], [HOEtMIm][NTf₂], [P_4,4,4,1][MeSO₄] and [P_4,4,4,2][DEP]. The contact angle results showed that compared with distilled water, the contact angles of ILs decreased, indicating good wetting effect. However, different ILs showed different wetting effects. Among of them, the [HOEtMIm][NTf₂] had the best wetting effect, the [P_4,4,4,2][DEP] and [P_4,4,4,1][MeSO₄] were in the second place, and the worst one was [HOEtMIm][BF₄]. The water-retaining experiments showed that the evaporation rate of coal containing ILs was slower and the water-retaining time was longer, indicating that the coal containing ILs had stronger resistance to moisture evaporation. The water-retaining property of [EMIm][BF₄] was the best. The FTIR experiments showed that the main structure of coal was not changed but some structures changed by ILs treatment. The significant changes were the aliphatic hydrogen groups (1435 and 1371 cm⁻¹), the C-O bond (1300–1000 cm⁻¹) and the mineral structures (1032 and 472 cm⁻¹). This study will provide a new development platform for the ILs used for coal dust prevention.

Under the concept of integrated technology for coal mine disaster reduction and carbon dioxide (CO₂) emission reduction, this study investigates the effect and mechanism of CO₂ storage through the mineralization of calcium carbide slag (CS) while exploring the inhibition effect of the resulting products on the spontaneous combustion of coal. The effects of different water-solid ratios, pressures, and rotational speed conditions on the mineralization of CS were analyzed. The results showed that the CO₂ storage of carbide slag was positively correlated with pressure, and the carbonation efficiency was negatively correlated with pressure. With the increase of rotational speed, the amount of CO₂ trapped by solid waste increases first and then tends to be flat (the increase of the CO₂ trapped amount is small when the rotational speed is higher than 900 rpm). The amount of CO₂ trapped in the solid waste was positively correlated with the water-solid ratio. Scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS) was used to analyze the microstructure changes of solid waste and mineralized samples. It was found that the particle morphology before and after mineralization produced many irregular calcium carbonate particles, and ESD results exhibited that the carbon content increased significantly. Moreover, it was found by gas chromatography that the CO production of the coal sample treated with carbide slag slurry decreased to varying degrees, which indicated the inhibition effect of mineralized products on natural coal processes, that the product after adding reinforced waste mineralized CO₂ had a certain inhibitory effect on the coal oxidation reaction, further providing a theoretical basis for exploring the collaborative utilization of solid waste and carbon resources in coal mines.

To tackle the dual challenges of large-scale disposal of coal-based solid waste and safe backfilling of goafs, while aligning with the “dual carbon” goals and enhancing mining area safety, carbon-negative backfilling technology has emerged as a key research hotspot in the field of green mining. However, it still faces issues such as low carbon sequestration efficiency and difficulty in additive recovery. In this study, two methods (NaOH and glycine leaching) were used to enhance the carbon sequestration capacity of coal-based solid waste, and their performance differences under optimal reaction conditions were systematically compared. The experimental results showed that the carbon sequestration capacity of the NaOH alkali activation group was only 26.96 g/kg, while that of the glycine leaching group reached 78.85 g/kg, which was significantly higher than that of the control group and the alkali activation group. Glycine rapidly captures CO₂ through its amino group to generate an active intermediate (carbamate), which greatly accelerates the absorption and conversion process of CO₂. Meanwhile, relying on its zwitterionic properties, glycine effectively buffers the pH value of the reaction system, inhibits the dissolution of CaCO₃ under acidic conditions, thereby promoting the stable precipitation of carbonates and ensuring the continuous progress of the carbon sequestration process. Detection of heavy metal concentrations in the leachate showed that their contents met national discharge standards. In addition, glycine can be recycled and regenerated during the reaction, which reduces additive consumption and demonstrates good economic viability and environmental compatibility. This study confirms that the glycine leaching method not only significantly improves the carbon sequestration efficiency of coal-based solid waste but also has the advantages of recyclability and environmental friendliness, providing a promising technical pathway for achieving efficient, long-term, and stable carbon sequestration in coal-based solid waste backfill materials.