Various types of slag are produced in the iron and steel industry, including blast furnace slag, pig iron ladle slag, converter slag and pouring ladle slag.
Blast furnace slag is produced during the manufacture of pig iron in the blast furnace. The slag is composed of various mineral components that have melted at high temperatures and separated from the actual molten metal.
Pig iron ladle slag is produced during the transformation of pig iron into steel in a pig iron ladle. Here, too, a slag is produced that consists of various mineral components.
Converter slag is produced during the manufacture of steel in a converter. The slag forms when the molten pig iron is injected into the converter, where it reacts with oxygen.
Ladle slag is produced when liquid steel is poured into a ladle. Here, too, a slag is formed consisting of various mineral constituents.
The mineral compositions offer opportunities for useful recycling. For example, slags can be used as building materials or as aggregates for road construction. Slags are also used in the cement industry as an additive that can improve the quality and durability of cement products. Another application can be found in the fertilizer industry.
Cement and concrete industry
Slags from the iron and steel industry can be used as valuable aggregates in the cement and concrete industry and in road construction. Slags can be used as so-called “cementitious material”. This makes them an important component of building materials, as they can improve the properties of concrete and cement and increase their durability, while the use of slags also helps to reduce CO2 emissions. The use of slags as a substitute for conventional cement constituents such as lime can reduce CO2 emissions and save costs.
Slags are also a valuable recycling material. By using slags as construction materials in road construction, resources can be conserved and waste reduced.
Slags from the iron and steel industry can also be used in the fertilizer industry. The slags contain valuable nutrients such as phosphorus and calcium, which are of great importance for plant growth. In addition, some slags also contain lime, which can regulate the pH of the soil.
By recycling slags as fertilizers, valuable resources can be conserved and waste reduced. The use of slags as fertilizer is therefore not only economically but also ecologically sensible.