What is Pig iron and How it is formed ?

All iron and Steel Products are derived originally from pig iron. This is the raw material obtained from the chemical reduction of iron ore in a blast furnace. The process of reduction of iron ore to pig iron is known as smelting. The main raw materials required for pig iron are :

(1) Iron Ore

(2) Cooking coal

(3) Flux.

Iron ores are generally carbonates, hydrates or oxides of the metal, the latter being the best. These Iron ores are found in India in Several States namely, Bihar, Orissa, Madhya Pradesh, Andhra Pradesh, Karnataka, Tamil Nadu, and Some other places.

The coke used in the blast furnace should be very high class hard coke obtained from good quality coking coals containing as low phosphorus and Sulphur as possible. It is produced by heating what is commonly called as "dry distillation" of the coking coals in coke ovens made of silica bricks in the absence of air to avoid giving off valuable gases. A light porous , sufficiently firm fuel which burns well is thus obtained.

Flux is a mineral substance that is charged into a blast furnace to lower the melting point of the ore and to promote the removal of ash, Sulphur and residues of the burnt fuel. Flux combines with the ashes of fuel and ore to form fusible products which separate from the metal as slag. The most commonly used blast furnace flux is the limestone. Dolomite is less frequently used. They come straight from the mines. In some cases siliceous alumina fluxes are charged into a blast furnace and in others, only silica.

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