Aluminum

                                    Aluminum

Aluminum comprised 1.3% of the United States municipal solid waste in the year 2006. Of the 3.3 million tons of aluminum produced, beverage containers and other packaging containers made up the majority. Approximately 99% of all beer and 97% soda cans are made of aluminum. After recovery, 2.6 million tons of aluminum was discarded in the municipal solid waste stream. In the same year, aluminum cans were recovered at a rate of 45% their generation and aluminum containers and packaging were recovered at a rate of 36% their production (EPA 2006). Aluminum is the third most occurring element in the Earth’s crust. It is never found independent of other materials in nature, and most commonly found in Bauxite. The process of producing aluminum starts with the harvesting or extraction of aluminum containing raw materials; Bauxite is the most frequently used source (Plunkert, 2000). The aluminum is then refined and sorted from other elements. The electrolysis of the resulting “alumina” in molten fluoride salt produces primary aluminum. This aluminum is cast into manageable ingots or billets through the smelting process. In addition to using large amounts of energy, the smelting process reduces 1.95 metric tons of alumina to 1 ton of aluminum (Plunkert, 2000). Two types of recyclable aluminum are produced: new scrap and old scrap. New scrap is comprised of discarded aluminum produced in factories that never made it to the public. Old scrap is aluminum discarded by the consumer. According to the Aluminum Association, the process of recycling aluminum cans saves 95% of the energy needed to produce aluminum from bauxite ore and other natural resources (EPA, 2006). In the year 2000, the efficiency of recycling old aluminum scrap was 42% (Plunkert, 2000). The energy intensive process of recycling old scrap requires that the discarded aluminum be transported, sorted, re-melted, and examined. The chemistry of the aluminum must be defined to insure the final product’s durability, composition, etc… If the recycling of new scrap is added to that of old scrap, the combined efficiency of recycling increases to 60% (Plunkert, 2000). The recycling of new scrap is less energy intensive due to the fact that the chemistry is already known; most new scrap does not leave the vicinity in which it was produced. The benefits of recycling aluminum are primarily the reduction in price of beverage containers and the reduction in energy consumption. The normal aluminum can contains 40% postconsumer recycled aluminum (EPA, 2006).

EPA. 2006. Municipal solid waste: Basic Information. United States Environmental Protection Agency. Updated January 29, 2008. URL: http://www.epa.gov/msw/alum.htm

Plunkert, Patricia A. 2000. Aluminum Recycling in the United States in 2000. United States Department of the Interior & United States Geological Survey. Updated May 9, 2006. URL: http://pubs.usgs.gov/circ/c1196w