Re-use and recycling have a long tradition in the European steel industry. Since the 19th century the sector has been using the process gas from melting iron ore in blast furnaces to produce energy used in other production steps. The gases deliver the heat required for coke plants and the ovens in the rolling mills, amongst other things. Together with the process gases from basic oxygen furnaces they are also used to generate electricity in power plants.
These plants are often situated right on the premises of the steel works. Integrated steel mills, which operate coke plants, sinter plants, blast furnaces, basic oxygen furnaces, continuous casting lines and rolling mills in an interrelated network, can produce much of the electricity they need from process gases. Although additional imports are still necessary, this energy cycle saves large amount of valuable natural resources. The electricity generated from the process gases of the European steel industry amounted to 30,000 GWh (gigawatt hours) in the year 2011. This amounts to the energy consumption of about 15 million people.
The steel industry produces not only metal, but also by-products which have been successfully used in many construction or agriculture applications. These non-metallic rock-like materials are called slags, or, to be more precise, ferrous slags. They originate in the metallurgical processes that extract iron from iron ore, turn iron into steel, or refine crude steel into one of the numerous different steel grades the European steel industry offers.
Each year an average 45 million tonnes of ferrous slags are generated from steelmaking in Europe. Far from being waste, slags are sought-after materials in numerous applications and they are always a sustainable alternative to natural resources. More than 80 per cent of ferrous slags are used for building roads, bridges or waterways. Slags with defined silicate content have been serving as fertilisers in agriculture for decades. Another important application for ferrous slags is cement production. Here, the use of granulated slag instead of clinker made from limestone reduces overall CO2 emissions from the cement production process. Go to EUROSLAG for mor information on this.