Sources of Magnesium Scrap New magnesium-base scrap can be generally categorized into four types. Type I is a high-grade scrap, which generally include materials, such as runners, gates, and drippings from die casting operations, which is uncontaminated with oils. Types II, III, and IV are lower grade materials in which type II is oil-contaminated scrap, type III is dross from magnesium-processing operations, and type IV is fines and chips.
The most desirable of these different types of scraps is type I, which is generated during die casting magnesium alloys. This scrap is either sold to a scrap processor or reprocessed at the die casting facility. The other types of scraps are either sold to a scrap processor or are utilized directly in steel desulfurization that is a dissipative application. Old magnesium-base scrap, or post consumer scrap comprises materials, such as helicopter parts, automotive parts, used tools, lawnmower decks, and the like. Scrap processors buy this scrap.
In addition to the magnesium-base scrap, considerable quantities of magnesium are incorporated in aluminum alloys, which can also be recycled. Although some magnesium is lost in the processing of scrap, a substantial quantity of the magnesium metal is recycled with aluminum alloy. New aluminum-base scrap, which is recycled, contains, in decreasing order of importance – primarily of solids, turnings and borings, dross and skimmings, and other materials that include foil and can-stock clippings. Because the primary aluminum product, which contains magnesium is beverage cans, the major magnesium-containing, aluminum-base scrap is can scrap skeleton obtained from lids and can sheet clippings. This corresponds to about 1/2 of the overall magnesium-containing, aluminum-base scrap.
Old aluminum-base scrap consists many materials, however the principal magnesium-containing component is used aluminum beverage cans (UBC’s). Due to the high recycling rate, aluminum beverage cans represent about three – quarters of the magnesium-containing, old aluminum-base scrap, which is reprocessed. The magnesium in old and new aluminum-base scrap is not separated from the aluminum alloy when it is recycled; instead, it is kept back as an alloying component. Therefore, the magnesium recycling industry depends on three primary components-UBC’s, old and new magnesium-base scrap, and new aluminum base scrap.