What is the Process of Smelting Iron ore?

Knives, forks, ships, trucks, and even bridges can be made from different types of steel. 

Steel is very strong and is one of the most useful materials in the world. 

Millions of tons of steel are produced each year.

Steel contains iron mixed with other metals and an element called carbon. Mixtures like this which contain mostly metal are called alloys. 

Like most other metals, iron is found in rocks. Rocks that contain iron are called iron ore. 

A part of iron ore is just useless rock, but the rest is iron or a compound called iron oxide. 

This compound is made up of molecules of iron arid oxygen. Before it can be used to make steel, the iron must be separated from the rock and the oxygen. 

This is usually done by a special heating method called smelting. Sometimes a process called direct reduction is used.

The smelting is done in a huge blast furnace. A large blast furnace can produce about 3,000 tons of iron in 24 hours

What happens in smelting?

Iron ore is mixed with limestone and coke. 

The mixture is tipped into the top of a blast furnace. 

A blast of hot air is blown into the bottom of the furnace. The coke, which is made from coal, burns easily and soon becomes very hot. 

A gas called carbon monoxide results. The carbon monoxide takes oxygen from the iron oxide. This reaction makes iron and another gas called carbon dioxide.

The iron then melts in the strong heat and trickles down to the bottom of the furnace. At the same time, the rock in the iron ore reacts with the heated limestone to make another liquid mixture called slag. 

This pours out separately and is sometimes used to make cement. 

The liquid iron is taken away to be cleaned and mixed with other liquid metals. The resulting mixture then hardens into steel.