Dust suspensions hybrid mixtures

Hybrid mixture A suspension of dust in air/vapor. Such mixtures may be flammable below the lower explosive limit of the vapor and can be ignited by low energy sparks. 

Suspensions of finely divided combustible solids (flammable dusts) can explode in much the same fashion as flammable gases. It is significant that, in a dust suspension in air, small concentrations of flammable gas, even well below the lower flammable limit of the gas, can contribute to a more severe explosion than that of the dust alone. Such mixtures are called hybrid mixtures. 

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