Aluminum, number 13 on the periodic table, is widely used in the construction, aerospace, automotive, and packaging industries. Favored for its light weight, high strength, corrosion resistance, good formability, electric and thermal conductivity, reflectivity, and non-toxicity, this element can be combined with other elements to further enhance its unique properties.
Aluminum is produced by the electrolyte reduction of alumina (Al2O3) and is converted into finished and semi-finished products by a variety of shaping processes. The aluminum produced directly from alumina is referred to as primary aluminum; aluminum can also be produced from scrap, called secondary aluminum. There are also two types of scrap in the aluminum life cycle. Scrap generated during the production of finished and semi-finished products is defined as primary scrap, while scrap generated from spent consumer and industrial goods is known as secondary or post-consumer scrap.
Scrap metal recycling is becoming increasingly important to the aluminum industry. Manufacturing aluminum from scrap yields an energy and green-house emissions savings of 95%. The production of secondary aluminum allows businesses to comply with environmental regulations, such as REACH and LEED, without any loss of quality. These environmental advantages, combined with a growing demand for aluminum fueled by industrialization in emerging markets and the growth of the automotive industry, is driving the aluminum industry toward a goal of 75% scrap integration into its production, with a substantial portion coming from post-consumer scrap.
However, the addition of scrap into the aluminum production line is a major challenge for the industry. Compared to the clean, neatly-packaged, and well-defined alumina raw material to which manufacturers are accustomed, post-consumer scrap is composed of a mixture of wrought and casting grades. The exact chemical composition of scrap, including the existence of contaminants or hazardous elements, is unknown. With end-product quality, process integrity, safety, and regulatory compliance at risk, accurate knowledge of the grade and composition of the scrap material being introduced into the process is a necessity.