Non-vacuum storage condition has a great impact on the explosion characteristics of aluminum powders. In this paper, vacuum-packed flake and globular aluminum powders stored in a dryer after opening the vacuum package...Non-vacuum storage condition has a great impact on the explosion characteristics of aluminum powders. In this paper, vacuum-packed flake and globular aluminum powders stored in a dryer after opening the vacuum package are selected as the experimental samples, and a 20 L spherical explosion device is chosen to test the minimum explosible concentration (MEC) values of aluminum dusts under different storage time. The results show that the MEC values of two types of unoxidized aluminum powders are 30 g/m^3. The MEC values of flake and globular aluminum powders firstly go up with the increase of storage time in the dryer and then reach the maximum values of 50 g/m^3 and 60 g/m^3 at respective storage time until finally they stabilize gradually. The main reason is that the oxidation rate is faster owing to the bigger specific surface area of globular aluminum powders. Hence, the storage time has more significant effect on the MEC of globular aluminum powder than that of flake aluminum powder. After a period of time, the outer surface is oxidized to generate a layer of film, which prevents the further oxidation of aluminum powder, resulting in the temporary stability of MEC.展开更多
文摘Non-vacuum storage condition has a great impact on the explosion characteristics of aluminum powders. In this paper, vacuum-packed flake and globular aluminum powders stored in a dryer after opening the vacuum package are selected as the experimental samples, and a 20 L spherical explosion device is chosen to test the minimum explosible concentration (MEC) values of aluminum dusts under different storage time. The results show that the MEC values of two types of unoxidized aluminum powders are 30 g/m^3. The MEC values of flake and globular aluminum powders firstly go up with the increase of storage time in the dryer and then reach the maximum values of 50 g/m^3 and 60 g/m^3 at respective storage time until finally they stabilize gradually. The main reason is that the oxidation rate is faster owing to the bigger specific surface area of globular aluminum powders. Hence, the storage time has more significant effect on the MEC of globular aluminum powder than that of flake aluminum powder. After a period of time, the outer surface is oxidized to generate a layer of film, which prevents the further oxidation of aluminum powder, resulting in the temporary stability of MEC.
