page 6
Making iron

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What do we need to make iron?
Making iron is the first step in the production of steel. Iron is usually made from iron ore, coal and limestone - although some plants around the world have developed alternative methods of iron manufacture.These newer methods require slightly different raw materials but iron ore, coal and limestone remain the starting point for most steel manufacture in the UK.

The original centres of the steel industry in the UK were on inland coalfield sites. They used iron ore, limestone and coal mined locally. As the demand for high quality steels increased, local ore and coal became less suitable, so these raw materials were increasingly imported from overseas. This led to a shift of the industry away from many of its original sites. The map shows the current sites of iron and steelmaking in the UK.
Photograph of sinter
Sinter about to be fed into the blast furnace.
Question 5i.

a) What do the present sites of iron and steel making plants in the UK have in common?
b) Why has the iron and steel industry moved away from its original coalfield sites?

Preparing the raw materials
Very little coal is used directly in the Blast Furnace to make iron. Most of the coal is packed into sealed ovens and heated strongly until it decomposes. This produces coke, a much purer form of carbon than coal.

Coke has three important jobs in the Blast Furnace:
  • it burns to give the very high temperatures required for Blast Furnace reactions;
  • it produces the carbon monoxide gas that reduces the ore to iron;
  • it is strong and supports the column of raw materials in the furnace. this allows reactive gases to pass through the furnace.
Much of the ore that comes to the steelworks is in a finely ground state. In this condition, the ore is difficult to handle without creating dust that can be wasteful and polluting. Heating a mixture of this loose material with fine coke from the ovens makes a much coarser material called sinter. Sinter is fed into the top of the Blast Furnace as well as coarse lumps of coke, limestone and iron ore.
Question 5ii.

What are the advantages of sintering the raw materials?