Review of the explosibility of nontraditional dusts

This paper explores the explosion characteristics of three nontraditional dusts: nanomaterials, flocculent materials, and hybrid mixtures. Nanomaterials have a high likelihood of explosion with minimum ignition energies potentially less than 1 mJ. These low ignition energies may therefore allow nanomaterials to ignite due to electrostatic sparks, collision, or mechanical friction. The severity of nanomaterial explosions is affected by agglomeration and coagulation of the particles. Flocculent materials with a high length-to-diameter ratio exhibit explosion behavior patterns similar to those for spherical dusts. The length of flocculent particles plays a role in explosion likelihood which is not yet fully understood. High voltage discharge during the electrostatic flocking process is a common flocculent ignition hazard. Hybrid mixtures of a combustible dust and a flammable gas/vapor display a higher explosion severity and a lower minimum explosible concentration than that of the dust alone. Violent hybrid explosions may occur even if the dust and the gas/vapor are below their respective lean limit concentrations. © 2012 American Chemical Society.