Iron and steel slag, also known as ferrous slag, is produced by adding limestone (or dolomite), lime and silica sand to blast furnaces and steel furnaces to strip impurities from iron ore, scrap and other ferrous feed materials and to lower the heat requirements of the iron- and steelmaking processes. In the production of iron, the blast furnace is charged with iron ore, fluxing agents, usually limestone and dolomite, and coke as fuel and the reducing agent. What is Steel Slag. During smelting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. Steel slag Aggregate (SSA) is a byproduct of the production of steel in an electric arc furnace. Steelmaking slag is an integral part of the steelmaking process. Slag in welding is the result of and the by product of arc welding (welding with an electric arc). … Slag is a coating. It was also ground into powder to add to glazes for use in ceramics. By far the most widely used material for building the world’s infrastructure and industries, it is used to fabricate everything from sewing needles to oil tankers. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. 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[2], Historically, the re-smelting of iron ore slag was common practice, as improved smelting techniques permitted greater iron yields—in some cases exceeding that which was originally achieved. Slag is a byproduct of steel production and is similar in character to volcanic rocks such as basalt and granite. At the same time the abrasion resistance tends to be enhanced (Anastasiou and Papayianni, 2006). The smelting of copper, lead and bauxite in non-ferrous smelting, for instance, is designed to remove the iron and silica that often occurs with those ores, and separates them as iron-silicate-based slags. Selected physical properties of steel slag are shown in Table 10.1. The raw materials - iron ore, coke and fluxes - are fed into the top of the furnace. Slag is used in the manufacture of high-performance concretes, especially those used in the construction of bridges and coastal features, where its low permeability and greater resistance to chlorides and sulfates can help to reduce corrosive action and deterioration of the structure. Molten slag diverted from the iron blast furnace is rapidly chilled, producing glassy granules that yield desired reactive cementitious characteristics when ground into cement fineness. Slag produced by steel mills is relatively abundant in industrial areas of the world and is often exported from steel production sites for use as fill material. However, slags can contain metal sulfides and elemental metals. The electric arc furnace slag aggregates showed tendency to expand, which is related to the presence of certain volumetrically unstable periclase and free line (Evangelista and de Brito, 2010). 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