The eighth most abundant element on the planet, magnesium constitutes about 2 % of the Earth's crust. In seawater, it is the third most plentiful element with an average concentration of 0.13 %. Though the metal is found in more than 60 minerals, carnallite, brucite, dolomite, magnesite, and olivine are of commercial importance. The metals is produced from seawater, lake brines and well, and bitterns, as well as from the minerals dolomite, carnallite, and magnesite.
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.