Possible Clues:

• Furnace or mill Ken and I rebuilt
• Furnace for calcium oxide production
• Fruit cocktail with the Italian Negroni on top of oven
• Industrial heater for citrus fruit needing link to cook
• Large oven for reducing calcium carbonate
• Kill me in grotesque calcium oxide oven
• Producer of calcium oxide
• Put meaningless filler back in paint — this produces calcium oxide
• Furnace (historic)
• Oven in which a caustic substance is produced