磷酸铵镁（MgNH₄PO₄·6H₂O）是污水处理管道中易生成的一种含磷管道堵塞物，为研究其对甲烷/煤尘复合爆炸的抑制效果，对磷酸铵镁晶体颗粒进行机械化学改性，制备了分散性良好的磷酸铵镁粉体（S-MAP），并用改进的哈特曼火焰传播实验系统研究了不同质量分数（20%、40%、60%、80%）的S-MAP对甲烷/煤尘复合爆炸火焰传播的抑制效果。实验结果表明：S-MAP的加入可以显著降低火焰传播速度、高度和亮度；随着S-MAP质量分数的提高，火焰传播高度由高于900 mm降低至134 mm，火焰传播平均速度由8.76 mm/ms降低至0.51 mm/ms；当S-MAP质量分数达到80%时，整个火焰传播过程只呈现微小火焰，可抑制住火焰的传播；抑爆机理方面，S-MAP分解能够吸收大量的热量起冷却作用，热分解产生的中间体能够吸附爆炸自由基以阻断爆炸链反应起吸附爆炸自由基作用，热分解产物能够稀释爆炸空间内氧气和可燃气体的浓度，同时热分解产物能够吸附在煤尘表面而隔绝氧气和热量的传递起窒息作用，三者的耦合效应抑制了甲烷/煤尘爆炸火焰的传播过程。

Magnesium ammonium phosphate (MgNH₄PO₄·6H₂O) is a phosphorus-containing blockage commonly found in sewage treatment pipelines. In order to study its suppression effect on the methane/coal dust composite explosion, magnesium ammonium phosphate was subjected to mechanized chemical modification to prepare well-dispersed magnesium ammonium phosphate powder (S-MAP). The improved Hartmann flame propagation system was used to investigate the suppression effect of different mass fractions of S-MAP(20%, 40%, 60%, 80%）on the flame propagation of the methane/coal dust composite explosion. The experimental results indicate that the addition of S-MAP can significantly reduce flame propagation speed, height, and brightness. With the increase of S-MAP addition ratio, the flame propagation height decreased from over 900 mm to 134 mm, and the average flame propagation speed decreased from 8.76 mm/ms to 0.51 mm/s. When the S-MAP addition ratio reached 80%, the entire flame propagation process only presented small flames, which could suppress the propagation of flames; in terms of explosion suppression mechanism, S-MAP decomposition can absorb a large amount of heat, thereby exerting a cooling effect. The intermediate produced by thermal decomposition of S-MAP can adsorb explosion free radicals to block the explosion chain reaction, thereby exerting the effect of adsorbing explosive free radicals. The thermal decomposition products of S-MAP can dilute the concentration of oxygen and combustible gases in the explosion space, and at the same time, the thermal decomposition products can adsorb on the surface of coal dust to isolate the transfer of oxygen and heat, thereby exerting a suffocating effect. The coupling effect of the three suppresses the propagation process of methane/coal dust explosion flames.