The Steel Industry

In the agglomeration, finely crushed limestone with a low sulphur and alkali content is used together with finely ground lime to form iron-ore sinters or pellets.

In the blast furnace, limestone pebbles are used to help remove the impurities during the transforming of ore into pig iron.

Pulverized quicklime is used for laddle desulfurization of the pig iron.

In the converters or electric arc furnaces where pig iron is processed into steel, quicklime is added as a flux to bind impurities such as silica, phosphorus, and sulphur which increase to the quality of the metal.  The lime reacts with the impurities to form a slag which can be removed. The lime used in steel production must have specific chemical and physical properties including a high calcium oxide content and a low sulphur, silica, and residual CO₂ content. It must also be highly reactive.