Effect and Mechanism of NH 4 H 2 PO 4 /Montmorillonite Composite Powder on Al-Mg Alloy Dust Explosion

The explosion of energetic metal dusts represents a major threat to the machining industry. It is therefore crucial to develop inexpensive, high-performance explosion inhibitors. For better protection of production, by using solvent-antisolvent approach, we prepare a uniquely clustered composite inhibitor by combining a natural clay mineral – Montmorillonite. In a 20-L spherical explosion apparatus and a vertical combustion tube, our examination shows that adding 80 wt% NH4H2PO4/Montmorillonite composite powder inhibitor can fully inhibit the explosion of Al-Mg alloy dust; adding 60 wt% composite powder inhibitor can inhibit the flame propagation. And that our new composite powder inhibitor outperforms pure monomer powder inhibitors. Through XRD, XPS, etc analysis, we gain a deeper insight into the inhibitory mechanism of NH4H2PO4/Montmorillonite. On the one hand, the decomposition of NH4H2PO4 and the resulting products combine to inhibit reaction; on the other hand, Montmorillonite contains plenty of voids that not only limits the propagation of flames, but also well absorbs the products generated from explosion reaction. Through research and experiments, we obtain a cheap, environmentally friendly and efficient composite dust explosion-proofing agent, which provides new ideas for the design of dust explosion-proofing materials and broadens the application prospects of natural clay minerals as dust explosion-proofing agents.