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2011 — Environment
Canadian Smelters Increase Recycled Spent Pot Lining to 90%
Lacking options in the Quebec region to recycle spent pot lining, Alcoa’s three Canadian smelters sourced alternatives in the United States and Germany that increased the amount of SPL they recycled to 90% in 2010 while saving US$2 million in costs.
Spent pot lining, also known as SPL, is the cathodic block (carbon) and insulation (refractory lining) of aluminum smelting pots that have reached the end of their service life. SPL consists primarily of carbon and refractory materials, along with lesser amounts of sodium, fluoride, cyanide, and other contaminants. In recent years, Alcoa has taken a leadership role in processing and converting SPL into a valuable raw material and alternative fuel source for use in the manufacture of cement, steel, and other products.
Government regulations for recycling SPL and an insufficient customer base in the Quebec region where the smelters are located stymied efforts to find a local economically viable recycling solution. As a result, the Canadian smelters sent a portion of their SPL to Alcoa’s Gum Springs, Arkansas, facility in the United States for processing.
In 2008, the smelters were recycling 11% of the SPL they generated through the Gum Springs plant. The following year, Alcoa Canada Primary Products initiated a project to maximize the amount of recycled SPL by segregating the carbon and refractory portions. The business sourced a German company that now uses a large portion of the carbon as an alternative fuel, a solution already employed by Alcoa’s smelters in Spain. The refractory portion is sent to U.S.-based cement manufacturers directly or through the Gum Springs facility, which also processes the remaining carbon material. Any additional material, such as the cathodic bar, is treated and recycled locally.
In 2010, the three smelters generated a combined 17,400 metric tons of SPL, of which 90% was recycled. They also saved US$2 million in transportation and disposal costs by implementing the new recycling solution. The goal for 2011 is 93% SPL recycled.