bHydropower, wood and wood waste, and municipal solid waste.
ABBREVIATION: EIA = Energy Information Administration.
SOURCE: EIA 2009e.
Energy for Heat in Steel Manufacture
Iron ores are mined as minerals in oxidized form. After cleaning and separation, the iron ore is reduced to pig iron in a coke-fueled blast furnace. Coke is the char material produced by heating bituminous coal in a sealed oven for 10 or more hours to drive off volatile “coal gases,” resulting in a char material called coke. Without proper effluent treatment, coke ovens can emit substantial amounts of dust and a wide range of emissions that come from various criteria pollutants. In a blast furnace, iron ore is reduced to pig iron by reaction with the coke and the formation of CO2. Energy was needed to produce the coke, but the coke reactions add some energy to the blast furnace. Further heat is required in additional refining steps in a basic oxygen furnace or an electric arc furnace.
When iron products are recycled, a much smaller amount of heat energy is needed to remelt them in an electric arc furnace than is needed in producing pig iron from mineral ores, partly because the reducing agents are not needed. Although it is difficult to compare “virgin” and “recycled” steel because nearly all steel is composed of some mix of recycled steel, the underlying processes are somewhat indicative of the difference between the two.Worrell et al. (2008, Table 1.1) gave “best practice” estimates of 14.8-17.8 GJ/tonne for a basic oxygen furnace and 2.6 GJ/tonne for a 100% scrap electric arc furnace.
the industrial sector in 2007, about 8 quads of it may be attributable to “nonfuel” purposes, such as the use of petroleum refining by-products in asphalt, feedstock for petrochemical products, and coal in the production of coke for steel making (EIA 2007, Table 1.5).2 However, although asphalt,
See EIA 2009j. These are the latest data available.