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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Brazil - 2011

Converting Trash to Cash at Poços de Caldas


In an effort to reduce its environmental footprint while simultaneously boosting its bottom line, Alcoa’s Poços de Caldas refinery and smelter complex in Brazil reused or sold more than 30,000 metric tons of industrial byproducts in 2010 for a combined income and cost savings of almost US$6.5 million.   


The initiative to recycle or find new uses for what historically was considered waste is driven by Alcoa’s global strategic sustainability goal to recycle or reuse 75% of landfilled waste by 2020 and 100% by 2030 from a 2005 baseline.


Poços de Caldas has focused on four specific byproducts: ESP dust, sweeping alumina, spent pot lining, and carbon products.


ESP dust, which is now called A50 in the commercial markets, is the alumina powder collected by the refinery’s dust collection system. Since 2006, A50 has been sold for reuse in refractories, fused alumina applications, and synthetic slag.


A85 is the commercial name for sweeping alumina, which is the alumina powder that is swept up from the potroom floor and is contaminated with various impurities. An Alcoa-developed sieving system reduces the impurities to the extent the byproduct can be reused in the facility’s smelting pots and also sold for fused alumina applications.


Spent pot lining, which is the carbon cathode and refractory material removed from the smelting pot at the end of its useful life, is co-processed by the cement industry. Between 2008 and 2010, the fee Alcoa pays for co-processing has decreased 14%.


The carbon products, which are purchased by the cement industry, include:

  • Cryolite carbon, a landfilled waste that remained from the site’s old cryolite recovery plant and which was completely eliminated in 2010;
  • Pot skimming, which is waste that rises to the top of the smelting pot and is skimmed off; and
  • C-45, which is carbon-rich waste from the potroom exhaust system.


Recycling or finding new markets and uses for all four byproducts reduced landfilled waste, generated income, and eliminated disposal and other costs. In addition, the location reduced environmental, health, and safety impacts in storing and transporting the materials.


Poços de Caldas 2010 Material Reuse
Material Metric Tons Generated Metric Tons Reused/Sold
A50 (ESP dust) 14,644 14,644
A85 (sweeping alumina) 1,600 1,570
Spent pot lining 2,970 11,420
Carbon products 2,519 5,302

Reuse/recycling numbers for spent pot lining and carbon products include material that was generated in prior years but reused or sold in 2010.