🚀 go-pugleaf

I am working on a research project to try to do something useful with the
sludge from wet flue-gas scrubbers in coal-fired power plants.  My problem
is that the power plants I have been getting samples from have taken to
adding thiosulfate along with the ground limestone to keep gypsum from
precipitating prematurely and plugging the plumbing.  This is wonderful for
the plant, but unfortunately means that the sludge is now mostly calcium
sulfite (CaSO3-0.5H2)) instead of gypsum (CaSO4-2H2O).  While gypsum has a
lot of uses (mainly plaster-of-paris and gypsum wallboard manufacture),
calcium sulfite seems to be a pretty industrially useless compound (except
for a few food applications, and the stuff from scrubbers is a long way
from being food grade).  So, my question is; Does anyone know of any
reasonably high-volume use for impure calcium sulfite, or of a reasonably
cheap, fast way of oxidizing it to gypsum? (the going rate for gypsum is
only about $7-$14/ton these days, so anything too expensive obviously won't
be very appealing to the power plants).  I am kind of running out of ideas
on this, and any help that anyone can give me will be very much
appreciated.
Thanks!

Tim Eisele
Research Associate
tceisele@mtu.edu