From lime stone CaO quicklime Ca2 is produced while {HEAD ~ CO2} is used in {TAIL ~ the production} of soda 
is used in
From lime stone CaO quicklime Ca2 is produced while { HEAD ~ CO2 } is used in { TAIL ~ the production } of soda
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH