Careful planning in the removal of a 20-year-old ring furnace at Alcoa’s Warrick Operations in Indiana resulted in about 90% of the 18,140 metric tons (20,000 tons) of demolished material being recycled. The project demonstrates that even demolition of something as large as a ring furnace can make a contribution to sustainability.
A ring furnace is used for the baking of carbon anodes, which are needed to produce primary aluminum. The furnace is made up of a network of hollow brick flues tied together with solid brick piers called headwalls. The flues are aligned side-by-side across the sections, and fire travels in a circle through the hollow brick flues to bake the anodes.
Built in 1983, the ring furnace at Warrick measured about 183 meters long (600 feet long) and 61 meters wide (200 feet wide) and contained 60 sections. Each section had 11 baking pits, and each pit was capable of baking 28 anodes at a time at 1,200°C (2,192°F) for 30 to 40 hours. It was the largest ring furnace in Alcoa.
By 2003, the furnace had aged to the point of inefficiency and needed to be replaced. The goal was to maximize the amount of furnace material that could be recycled.
A total of 16,190 metric tons (17,845 tons) of ring furnace brick were crushed and recycled for use as a raw material in the manufacture of cement. Additionally, approximately 136 metric tons (150 tons) of metal from the furnace were recycled. Only about 1,814 metric tons (2,000 tons) of wastes, mostly concrete and brick not clean enough to be recycled, required landfilling.
Due to the recycling efforts, Warrick saved approximately $250,000 in the demolition and replacement project.
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