Quite a lot of powders burn.
Basically anything that is organic, and a fine powder, will explode under the right conditions.

Part of my work involves loading terminals at ports. In the course of my career have seen several grain terminals go up, usually dust from wheat or corn, and for the really big bangs what you want is a sugar terminal.

We built one in France. To get into it you had to empty your pockets and wear a special non static suit, and a hat that stopped you touching your hair, which could in theory produce a spark.

Oh, I beleive coal dust goes up well too. Never seen that though.
(username failed moderation, Fri 10 Aug 2012, 9:14, 1 reply)

And some metal powders (e.g. iron and zinc) can spontaneously ignite in air.

( The Mock TurtIe ™ --- Thinks you are a cunt, on, Fri 10 Aug 2012, 20:43, closed)