Explosive Dust Mixtures

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Explosive dust mixtures Explosive dust mixtures: A dust explosion is the fast combustion of dust particles suspended in the air in an enclosed location. Dust explosions work best with coal dust in underground coal mines (since a mine is a closed environment) however dust explosions can occur where any powdered combustible material is present in an enclosed atmosphere. The requirements for a dust explosion can be called the explosion pentagon. There are five main components which are needed for a dust explosion. 1) An oxidant- this is usually atmospheric oxygen, but it can be other oxidants such as fluorine, chlorine and bromine. 2) A combustible dust- this can be coal dust as an example. 3) An ignition source- something to set off the explosion. 4) High concentration- this means the explosion is effective and strong. 5) Confinement of dust cloud- in confined spaces the explosion would work better. Small particles (e.g. flour/ saw dust) have much more surface area than a large, solid object. This means that when in air they can explode and result in impressive explosions. Small particles confined in a small area that can cause explosions can be any of the following: coal dust, saw dust, grain, flour, sugar, powdered milk, pollen. In addition to these many powdered metals (e.g. aluminium and titanium) can form explosive suspensions in air. Causes of dust explosions can be any of the following: 1) Transporting grain 2) Mining of coal leads to coal dust 3) Flour mills have large amounts of flour dust as a result of milling and this can result in an explosion. 4) Saw mills have lots of Saw dust. To cause the explosion the dust must consist of very small particles with a high surface area to volume ratio, thereby making the collective or combined surface area of all the particles very large in comparison to dust of larger particles. Dust is defined as
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