A compartment is provided within {HEAD ~ the kiln} for selectively introducing {TAIL ~ a reducing agent} into the chamber 
A compartment is provided within { HEAD ~ the kiln } for selectively introducing { TAIL ~ a reducing agent } into the chamber
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH