Possible Clues:

• Criticise features about vessel that's vital for smelting
• Dilutes coke and crack from a very hot place
• Smelter's need
• Blair listens from very hot place to one of those diluting coke
• Coke product maker
• Blaze excellent, surrounding ultimate source of fiery hot spot
• Black coat worn by most recent new champion smelt here
• Where iron may be smelted
• Heated chamber for smelting iron