Case Studies

These case studies illustrate how Alcoa is acting upon its commitment to sustainable development throughout the world. We are pleased with this progress, but look forward to achieving even more.

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2007 — Environment

Testing hybrid pitch at the Söderberg pots

To meet future government environmental standards, the Baie-Comeau aluminum smelter is working on reducing its polycyclic aromatic hydrocarbon (PAH) emissions, which are produced during the combustion of briquettes in the anodes of the Söderberg pots.  The new standards will be 0.30 kg/metric ton of aluminum (mt Al) and, in 2010, they will go down to 0.20 kg/mt Al.  We have conducted tests to replace the 100% coal tar pitch currently being used by a hybrid pitch made of 60% coal tar pitch and 40% petroleum pitch.  This type of pitch could enable us to significantly reduce our PAH emissions.
An initial series of tests was conducted in the A2 East workroom between November 2005 and January 2006.  With a 30% reduction in PAH emissions recorded during this period, the results led to a second round of tests in the A2 West workroom from June to August 2007.  This period is especially critical because of summer weather conditions.
We are optimistic that the second sampling will confirm the compelling reductions obtained in the first round of tests.