Recycling and Scrap Melting: Process Descriptions
Courtesy of the Aluminum Association.
Aluminum secondary smelting (scrap recycling) accounts for approximately 33% of all primary aluminum produced in the U.S. There are approximately 68 major secondary processing plants in the U.S. These processing plants are typically located near large urban areas where large supplies of scrap aluminum are available. Aluminum recycling and secondary smelting requires preprocessing of the scrap aluminum to remove impurities, followed by remelting of the aluminum. To maintain sufficient purity, the remelted aluminum is mixed with pure aluminum produced in a primary smelting plant (typically a 50-50 mix). Prior to melting various mechanical, thermal, chemical, and magnetic techniques are used to separate contaminants and non-aluminum materials from the scrap. in contrast to the electricity intensive process of primary aluminum smelting, melting of scrap to yield secondary aluminum involves primarily natural gas usage.