The surface of the crucible 10 is covered by a housing 18 into which a reducing gas is introduced at {TAIL ~ an inlet} 19 so as to flow generally contrary to the flow of metal in the crucible 10 which will thus be exposed to {HEAD ~ the reducing action} of the gas 
The surface of the crucible 10 is covered by a housing 18 into which a reducing gas is introduced at { TAIL ~ an inlet } 19 so as to flow generally contrary to the flow of metal in the crucible 10 which will thus be exposed to { HEAD ~ the reducing action } of the gas
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH