I see a big problem with that, unless there are dust collectors out there that are made significantly differently than the ones I'm familiar with.  Most dust collectors have an impeller consisting of a flat plate with 4-5 vanes welded on.  They have a motor directly coupled to this plate and the inlet is on the center of the housing surrounding this plate.  Anything that goes through the dust collector is sucked through this inlet, impacts the center of the plate, and then gets blown through just like in a silage blower.  Not real conducive to handling grain, unless you want to crack corn, and probably not too good at that either.  Just thought I'd mention it.

Mike