Experimental study on inhibition of coal spontaneous combustion by carbon sequestration products from typical industrial solid waste mineralized CO2

Using solid waste mineralization to fix CO₂ and mineralization products to plug air leakage in goaf is an effective way to reduce carbon emission, which has the advantages of large consumption of solid waste and significant safety. In this research, the ability of typical alkaline solid wastes such as fly ash and steel slag to mineralize CO₂ and the effect of mineralized products on the prevention of coal spontaneous combustion were explored. SEM-EDS, XRD and Fourier infrared spectroscopy were 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 EDS results exhibited that the carbon content increased significantly. XRD results exhibited that CaO diffraction peak disappeared and CaCO₃ diffraction peak replaced it in solid waste after mineralization. FTIR results further appeared that the presence of carbonate ions in the samples before and after the reaction indicated the formation of CaCO₃. Moreover, it was found by temperature programmed that adding waste slurry to the coal powder could significantly increase the temperature at the intersection point of the coal, finally indicating that the product after adding reinforced waste mineralized CO₂ had a certain inhibitory effect on the coal oxidation reaction, further providing the theoretical basis for underground coal mine fire prevention materials prepared by industrial solid waste mineralization reaction.