Will flour explode?

Friends who have seen the TV series "The Pretender" should still remember the fragments of the fried flour mill, right? To destroy the evidence, Cheng blew up the flour mill. However, he didn't use explosives or gasoline. He just cut several bags of flour and sprinkled it into the air.

Then throw the lit lighter into the flour.

Bang! The flour mill exploded!

Why does dust explode?

When the dust meets an open flame or high temperature within the explosion limit, the flame instantly spreads in the whole space where the dust is mixed, and the chemical reaction speed is extremely fast, at the same time, a large amount of heat is released, forming high temperature and high pressure. In this process, there will be rising pressure to produce shock waves, so the destructive power of dust explosion is also very great.

Dust explosion is essentially a violent redox reaction. With oxygen in the air as oxidant and combustible dust as reductant, in a relatively closed environment, especially in some factories and workshops, when its concentration is between the lower limit and the upper limit of explosion, there will be a danger of explosion at this time. If there is an open flame, the equipment releases an arc, electrostatic discharge, and even sparks are generated by friction. When flammable dust comes into contact with oxygen, a violent redox reaction will occur, leading to dust explosion.

In addition to reaching a certain concentration, dust explosions are also caused by their very small volume and large surface area. With the increase of surface area and contact area, the reaction will become more rapid.