Abstract： To evaluate the combustion and explosion characteristics of Mg-Al alloy powders, a Hartmann apparatus was used to study the effect of dust concentration, particle size and the particle size of inerting agent calcium carbonate on minimum ignition energy （MIE） of Mg-Al alloy powders. The mean size of Mg-Al alloy particles used in the experiments were 15, 38, 75 and 120 μm respectively and the mean size of calcium carbonate particles were 5, 21 and 38 μm. The results show that, for the same size of the alloy powders, the value of MIE first decreases and then increases as the concentration from 100 g/m³ up to 1 800 g/m³. The value of MIE increases with the increase of particle size of alloy powders. Calcium carbonate has a great effect on MIE of powders. When the particle size of calcium carbonate becomes smaller, the inerting effect is more obviously.

Keywords: Mg -Al alloy powder; minimum ignition energy; particle size; dust concentration