Experiment-based fire and explosion risk analysis for powdered magnesium production methods

More than 100,000 tons of powdered or granular magnesium are produced annually in China in factories with high potential fire and explosion risk. The primary methods for magnesium powder production are reviewed in this paper. Fire risk analyses, based on minimum ignition energy (MIE) and minimum ignition temperature (MIT) test results for magnesium powder of different diameters, are provided for each method. Sparks caused by static electricity, mechanical friction, or impact are the most likely ignition sources for fine magnesium powder fires and explosions. However, MIT of powdered magnesium was much higher than that of organic or coal dust even for very fine magnesium powder. Magnesium powder fires and explosion were not readily caused by hot surfaces. A two-stage combustion model was experimentally determined for a magnesium dust layer.