Limestone is an essential raw material
A wide range of Nordkalk lime products is used when iron ore is processed into steel. The production of each tonne of steel requires more than 50 kg of quicklime. Lime forms a highly basic slag, which purifies iron ore to form the final steel product after a complicated process chain.
Iron ore pellets are stable and homogenous and therefore easy to transport and load into the blast furnace. Limestone and lime are used to make iron ore pellets. An alternative raw material for the blast furnace is iron ore sinter. Limestone and lime added to the sinter react with impurities and balance the slag composition of pig iron production.
Pellets and/or sinter are charged into the blast furnace together with limestone and coke. All raw materials smelt down forming pig iron and slag. Reliable raw materials, like good quality lime products, are essential for maintaining efficient blast furnace operation and a high pig iron quality.
Excess sulphur and phosphor are removed from pig iron with special lime products. Such products are fine quicklime powder with added ground limestone. In the steel making processes recycled metal and/or pig iron, flux and lumpy lime are melted down in a furnace. The LD- process uses pig iron and electric arc furnaces use recycled metal as the main metal carrier. During the melting processes lime produces slag, which in turn picks up impurities from steel.
The ladle furnace process is mainly used to adjust the analysis and temperature of steel before casting. Lime products melt and form a purifying top slag on top of the steel in the ladle. Slag efficiently decreases heat loss during processing.
Finally, liquid steel refined with lime is cast in a continuous casting process to make slabs or billets for further processing into final steel products.
Selecting the most suitable lime product ensures easy process control, which helps to match the target quality - and maintain low processing costs.
Nordkalk is the leading limestone company in Northern Europe. We deliver essential raw materials to numerous industries, and our solutions contribute to clean air and water as well as productivity of agricultural land.