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