Of all the metals, iron is the most important to us. This is mainly because it can be made into the alloy ‘steel’. Iron is one of the most widely available metals — more iron is produced each year than all the other metals put together.
Iron ore is often found combined with other substances, such as oxygen, silicon, sulphur or carbon. The metal is usually separated from these substances in a blast furnace. The intense heat of the furnace makes a fairly pure molten iron.
Most of the molten iron is used for making steel; some is further used as cast iron or as wrought iron.
Iron can also be smelted in an electric furnace.
Smelting in a blast furnace
Iron is extracted by smelting, or heating its ores. This is heated in a giant oven called a blast furnace. The fuel burned to make the heat is called coke. The burning coke combines with the oxygen in the air to make the gas carbon dioxide. This gas escapes through the top of the furnace. Impurities from the ore (oxygen and silicon) combine with limestone to make ‘slag’. Limestone soaks up these various substances to leave fairly pure iron.
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