镁粉尘云最低着火温度的实验测试

采用标准装置Godbert-Greenwald恒温炉测试了不同条件下镁粉尘云最低着火温度。实验测试结果显示:D50为6、47、104、173 m时镁粉尘云最低着火温度分别为480、520、620、700 ℃;选取D50为6 m的镁粉，在分散压力恒定为0.1 MPa时，镁粉浓度由424 g/m3变化到5 085 g/m3，粉尘云最低着火温度由600 ℃降低到480 ℃;而粉尘质量恒定为0.3 g时，分散压力从0.1 MPa增加到0.2 MPa，粉尘云最低着火温度由540 ℃升高到580 ℃。还分析了镁粉粒径、浓度及分散压力对粉尘云最低着火温度的影响。

Measurement of minimum ignition temperature for magnesium dust cloud

A standard Godbert-Greenwald furnace apparatus was used to measure minimum ignition temperatures of magnesium dust cloud under different conditions. Experimental results reveal that corresponding minimum ignition temperatures of dust cloud for four magnesium specimens with the medium grain diameters D_(50) of 6, 47, 104 and 173 Mm are 480,520,620,>700℃ , respectively. Take the magnesium powder with the grain diameter of 6 pm for example, under the constant diffusing pressure of 0.1 MPa, the minimum ignition temperature of the magnesium dust cloud decreases from 600 ℃ to 480℃ corresponding to the dust concentration changing from 424 g/m~3 to 5 085 g/m~3; and for the constant dust mass of 0.3 g, when the diffusing pressure increase from 0.1 MPa to 0.2 MPa, the minimum ignition temperature of this magnesium dust cloud increases from 540℃ to 580 ℃. And effects of grain diameter distribution, concentration and diffusing pressure on the minimum ignition temperature of magnesium dust cloud were analyzed by the above experimental results. It is helpful in the explosion-proof equipment design for the magnesium powder production.