Assessment of the Flammability of Dispersed Components of the Mining Industry Waste

Waste dumps are the man-made wastes of the mining industry. Particles of magnesium and aluminum are part of waste dumps and emissions from their combustion. Release of the dispersed particles of these metals leads to the spread of fire on the surface of the waste dump and beyond. Assessment of the dispersed composition of magnesium and aluminum particles, their flammability and the induction period allow to predict the fire hazard of rock dumps and the surrounding area. This contributes to ensuring the environmental safety of mining agglomerations. The most probable particle sizes of its oxide were established by sedimentation analysis of metallic magnesium scale. It was experimentally determined that the maximum temperature, at which magnesium particles of any fraction do not ignite, is 983 K. When the temperature reaches 1053 K, ignition of magnesium particles of all the rock dump fractions occurs, and at 1243 K, aluminum particles. The induction period for magnesium particles 1∙10–4 m in size at a temperature of 1053 K is 0,057 s. With increasing temperature, it decreases linearly. It is established that with an increase in temperature, the particles of the fraction 4,9∙10–5 m are the first to burn. The last to flash are the smallest particles of 6∙10–6 m. During research it was found that at the fixed particle sizes, an increase in temperature leads to a rapid reduction in the induction period. Its drop is observed at temperatures close to the flammability temperatures of the particles. An increase in the mass of magnesium particles leads to an increase in the induction period.