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Slag
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<p>Slag is a <a href="/facts/By-product/qDosnqoD">by-product</a> or co-product of <a href="/facts/Smelting/Ghdvhlga">smelting</a> (<a href="/facts/Pyrometallurgy/VuhDQhUj">pyrometallurgical</a>) <a href="/facts/Ore/kgc9DssX">ores</a> and recycled metals depending on the type of material being produced. Slag is mainly a mixture of metal <a href="/facts/Oxide/DXtoVe1C">oxides</a> and <a href="/facts/Silicon_dioxide/A3WILp6J">silicon dioxide</a>. Broadly, it can be classified as <a href="/facts/Ferrous/AGImjWqq">ferrous</a> (co-products of processing iron and steel), <a href="/facts/Ferroalloy/0NfDFfQE">ferroalloy</a> (a by-product of ferroalloy production) or <a href="/facts/Non-ferrous_metal/lY7X8rAY">non-ferrous</a>/<a href="/facts/Base_metal/H1EpE5DU">base metals</a> (by-products of recovering non-ferrous materials like <a href="/facts/Copper/I8PEE8oX">copper</a>, <a href="/facts/Nickel/KwMCHYRP">nickel</a>, <a href="/facts/Zinc/80b1qgk3">zinc</a> and <a href="/facts/Phosphorus/27xCeIqs">phosphorus</a>). Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., <a href="/facts/Blast_furnace/DJzUB2EG">blast furnace</a> slags, air-cooled blast furnace slag, granulated blast furnace slag, <a href="/facts/Basic_oxygen_furnace/yg5Ht8fC">basic oxygen furnace</a> slag, and <a href="/facts/Electric_arc_furnace/GgYK6Nz1">electric arc furnace</a> slag). Slag generated from the EAF process can contain toxic metals, which can be hazardous to human and environmental health. </p> <p>Due to the large demand for ferrous, ferralloy, and non-ferrous materials, slag production has increased throughout the years despite recycling (most notably in the iron and <a href="/facts/Steelmaking/95arHmry">steelmaking</a> industries) and <a href="/facts/Upcycling/33x35tQE">upcycling</a> efforts. The <a href="/facts/World_Steel_Association/dkotJUdQ">World Steel Association</a> (WSA) estimates that 600 kg of co-materials (co-products and by-products; about 90 <a href="/facts/Mass_fraction_(chemistry)/YMIH9egn">wt%</a> is slags) are generated per <a href="/facts/Tonne/gMymLmWv">tonne</a> of steel produced. </p>