Why are Grain Dust explosive?

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I realise that this topic is more towards chemistry however i was wondering why grain dust particles are explosive. Is there any carbon atoms in the dust particles that fuel these explosions?
 

A.T.

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Borek

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It is mostly kinetics of combustion - there is a huge surface on which combustion can take place, so it happens very fast. Same story with coal dust.

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Same with almost any dust. I've read (although with no source attached) that you could make asbestos dust explode if it were fine enough. Certainly this is the case for fine metalic dusts
 

Borek

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Not any dust - it has to be able to react with oxygen giving off heat. Otherwise it won't work (which makes me strongly doubt asbestos idea).

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Sounds right. The article was pointing out that even elements or compounds which only react very reluctantly with oxygen (which leaves me with visions of teenager type elements sitting in a corner refusing to react) will do so explosively when in dust form.

A quick wiki search shows that there are at least 3 different types of asbestos - all chemically very different. My A-Level chemistry didn't prepare me well enough to deal with reactions of
Na2Fe2+3Fe3+2Si8O22(OH)2
(Blue Asbestos)!!
 
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do these dust particles require an igniter or can they simply combust through their own kinetic energy through friction?
 

Borek

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Never heard about them exploding without ignition.

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Borek

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Na2Fe2+3Fe3+2Si8O22(OH)2
(Blue Asbestos)!!
Well, Fe(II) can be oxidised to Fe(III), so perhaps there is a slight chance of reaction taking place. Which shifts my doubts from 'strong doubts' to 'just doubts' :wink:

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alxm

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do these dust particles require an igniter or can they simply combust through their own kinetic energy through friction?
Statistically very unlikely. Or simply: I don't think so.

What'd be more likely is the dust and friction causing a discharge of static electricity which could act as an ignition source.
 
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Statistically very unlikely. Or simply: I don't think so.

What'd be more likely is the dust and friction causing a discharge of static electricity which could act as an ignition source.
^^ yea that makes more sense. thankyou
 

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