C6.1.7 - Extracting iron

Question 1

What is a blast furnace?

Answer 1

Industrial reaction vessel for iron production

Question 2

What raw materials are added to the top of the blast furnace?

Answer 2

• Iron ore
• coke, which is mostly carbon, and is made by heating coal in the absence of air
• limestone, which is used to purify the iron

Question 3

What happens in a blast furnace?

Answer 3

• Coke burns in the hot air, making carbon dioxide
• More coke reduces the carbon dioxide, making carbon monoxide
• Carbon monoxide reduces iron(III) oxide to iron at around 1500C
• Calcium carbonate decomposes in the high temperatures
• The calcium oxide formed reacts with silica from the Sandy impurities to form calcium silicate
• This floats on the molten iron and is removed with iron