Experimental Research On Magnesium Dust Explosion And Its Risk Assessment

Magnesium powder was a representative product with high tech in recent years. However, great hazard of fire & explosion exists during producing, transporting, storing, and employing because of its high activity, and had great effect on regular production of magnesium powder However, the descriptions of experimental and theoretical research on magnesium powder are lacking, and the results from some literatures were determined in different experimental configurations, making a systematic data analysis very challenging.At first, under several conditions some experiments for various magnesium powder have been done in 20L ball, Godbert-Greenwald (G-G) and other testing rigs which were configured based on international standard, and the factors which affect on the magnesium powder explosion were analyzed. In atmosphere some parameters for four magnesium specimens whose D50 was 6μm,47μm,104μm and 173μm were determined, including Pmax, (dp/dt)max, Kst, MEC, MITC, MITL and MIE. Then, as a representative specimen, Pmax,(dp/dt)max,Kst of magnesium powder whose D50 was 47μm was determined with different concentration of nitrogen, argon, and carbon dioxide. Finally, the MIE and LOC of magnesium powder whose D50 was 6μm,47μm,104μm was determined in this condition with insufficiency of oxygen.The results show that with decreasing diameters some parameters are increasing, includingPmax, (dp/dt)max, Kst, and others are decreasing, including MEC, MITC, MITL and MIE. Moreover, some parameters including Pmax, (dp/dt)max, Kst, have a maximal value when an appropriate concentration is ready. Before it, the value of these parameters is increasing with increasing concentration, and is decreasing after it. However, MITC was decreasing during the whole process. In insufficient oxygen due to nitrogen, argon, and carbon dioxide, with increasing diameter the violence Parameters were decreasing in a whole, and LOC was increasing. It is found that nitrogen is the best inert media among three considered gases on the basis of the comprehensive comparison of LOC in insufficient oxygen. Finally, a two-stage model which includes solid and gas phase combustion was found, according to the observation in experiments determining MITL.According to experimental results mentioned above, the software for data query was developed with Microsoft Access and Visual Basic.NET.Finally, explosion risk of magnesium powder was evaluated according to its characteristic, production technique and productive facility.