Fine powder explosion 

Chief Scientist Carl Nelson demonstrates the combustion of a fine powder in a sealed container.
A sparkler acts as the ignition source for this explosion. A squeeze bottle filled with lycopodium is used to create a fine mist inside the sealed paint can. The large surface area of the powder allows it to rapidly combust. In doing so, the air inside the container heats up and expands, blowing the lid off the can.
This is a small scale version of what can happen in a grain elevator filled with fine grain particles and an ignition source.