Page 336 - Design for Environment A Guide to Sustainable Product Development

Materials Pr oduction Industries 311

At each stage, the concept must undergo technical and environmen-
tal assessment, commercial analysis, and stakeholder engagement.
In addition, any proposed waste reuse must be in accordance with
environmental laws and Alcoa standards for waste management.
Beginning in 2008, customers must be certified and audited by a
third-party company to ensure they are in compliance with the re -
quirements for handling, storing, and using waste approved for com-
mercial use.
As an example, Alcoa’s Brazilian refineries and smelters have
made significant progress in diverting production wastes from the
landfill and converting them into commercially viable products—
minimizing their environmental impact and providing a new source
of revenue. Examples of successful waste conversion include

• Carbon Cryolite. This waste, which had accumulated from
results from the Soderberg smelting process, has been devel-

oped into an alter native fuel for the cement sector. Alcoa’s
Poços de Caldas smelter sells approximately 1,000 metric
tons each month, which will allow it to eliminate all of this
stored waste by mid-2009. The smelter has not produced any
carbon cryolite since 2003.
• Aluminum Oxide Dust. Since 2004, Poços de Caldas has
been selling all of its aluminum oxide dust collected from the
calciner department at the refinery as an alumina source for
the enrichment of chamot—an inexpensive refractory aggre-
gate. A second application for the dust is being developed
for the Alcoa smelter in São Luís, Brazil, which is located too
far from most refractory producers.
• Boiler Coal Dust. São Luís is currently selling the coal dust
generated from its boilers as another alternative fuel source
for the cement industry. Almost 12,000 tons of the dust is
being diverted from the landfill each year.

Other wastes that are either being sold or provided to other
industries include some mineral wastes as well as spent pot lining
(SPL), which is generated when the carbon and refractory lining of
smelting pots reaches the end of its serviceable life. Currently, Alcoa’s
two Brazilian smelters are providing 30,000 metric tons of SPL annu-
ally to the cement industry to use for fuel and a source of fluoride.
The Brazilian locations are also investigating several potential
commercial applications for bauxite residue, the largest volume waste
of the refining process. They are working closely in this effort with
Alcoa’s Australian researchers, who are also developing processes to
convert the residue into a raw material for a variety of applications.
Primary initiatives including converting the residue for use in the
ceramic tile, agriculture, and cement industries.