Blast Furnace Raw Materials
The blast furnace is the cornerstone of modern steel production. It is fed with iron ore, coke and limestone, and is used to produce molten iron that is then processed to make steel. Iron ore and coke are added at the top of the blast furnace while limestone is added at the bottom. The addition of these materials is called charging the furnace and requires an understanding of their respective chemical and physical properties.
Iron ore is the raw material used to make pig iron, which is one of the main materials to make steel. 98% of the hauled out iron ore is used to produce steel. In production of steel there are two main stages, the first is the production of pig iron which takes place in the blast furnace, and the second is the production of steel which takes place in a steel making furnace. The ore used for the production of pig iron is found in the form of magnetite (Fe3O4), hematite (Fe2O3) as well as many other types of iron oxides.
Coke is used as a fuel and as a reducing agent in the blast furnace for smelting iron ore. Coke is a carbonaceous solid created by heating coal in the absence of air. In its pure form it is a dark, glossy, non-porous solid. Coke also helps to maintain the required temperature of the furnace by releasing heat when it burns. It also opens the furnace to air which is needed to complete the smelting process.
Limestone is used in the blast furnace to help reduce the temperature of the furnace and also to remove impurities from the iron ore and coke. It is added at the bottom of the furnace in the form of pellets or powdered limestone. When the furnace is full, the limestone reacts with the hot coke and partly forms a slag that floats on top of the molten iron. This helps to keep the furnace cool and also removes impurities like phosphorus from the iron ore and coke.
In conclusion, the three raw materials used in the blast furnace are iron ore, coke and limestone. Understanding the chemical and physical properties of these materials is essential for successful operation of the blast furnace. Together, the combination of these materials is part of what makes steel production possible.
