Inhibitory effect and mechanism analysis of modified coal gangue powder on the methane–air explosion

The application of industrial solid waste coal gangue (CG) in gas explosion suppression is explored, which opens up a new way for the resource utilization of CG. Two modified CG anti-explosion agents, first-grade modified CG (RCG) and second-grade modified CG (MCG), were prepared by roasting activation and acid–base synergistic excitation. The explosion suppression performance of CG, RCG, and MCG was investigated through a 2.5 L semi-closed explosion pipe. The experimental results were compared and analyzed, and their pyrolysis characteristics, phase composition, and particle size were analyzed to reveal their explosion suppression mechanism. It was proved that MCG had the best explosion suppression effect. Under the condition of 9.5% methane–air, it was found that the explosion suppression effect was most significant when the powder mass of the three powders was 300, 360, and 360 mg, respectively. The peak explosion overpressure is reduced by 10.51%, 21.96%, and 32.66%, respectively, and the peak arrival time of flame velocity is extended by.14 times,.20 times, and 1.15 times, respectively. MCG can effectively inhibit methane explosion utilizing physical and chemical synergistic heat absorption, porous structure formation barrier, heat isolation, oxygen dilution, adsorption, and capture of free radicals.