Blast Furnace ReactionsCarbon oxidised by hot air:

Carbon(s) + oxygen(g) carbon dioxide(g)

C(s) + O2(g) CO2(g)

Carbon oxidised by carbon dioxide:

Carbon(s) + carbon dioxide(g) carbon monoxide(g)

C(s) + CO2(g) 2CO(g)

Carbon monoxide reduces iron (III) oxide:

Carbon monoxide(g) + iron (III) oxide(s) iron(l) +

carbon dioxide(g)

3CO(g) + Fe2O3(s) 2Fe(l) + 3CO2(g)

Exercise 7: The Conditions in the Blast Furnace

1. What is the role of coke in the blast furnace?

2. What is the role of limestone in the blast furnace?

3. Which ore of iron is commonly used in the blast furnace?

4. Why is it called a blast furnace?

5. What do we call the layer of impurities that forms at the base of the blast furnace above the liquid iron?

It acts as a reducing agent

Limestone helps to remove acidic impurities

Haematite

Because hot air is ‘blasted into the furnace’

Slag

Exercise 8: Direct Reduction

1. Which compound does haematite mainly consist of?

2. What is the chemical formula of this compound?

3. A small amount of this compound is directly reduced by the coke, what does reduced mean in this instance?

4. Write a word equation for this reaction.

5. Write a chemical equation for the word equation above.

Iron (III) oxide

Fe2O3

The oxygen is removed from the compound

Carbon(s) + iron (III) oxide(s) iron(l) + carbon dioxide(g)

2Fe2O3(s) + 3C(s) 4Fe(l) + 3CO2(g)

Exercise 9: Limestone

1. Limestone is added to the blast furnace to remove acidic impurities. What is the name and chemical formula of the compound that limestone mainly consists of?

2. In the blast furnace this compound undergoes thermal decomposition. Write a word equation for this reaction.

3. What is the chemical equation for this reaction?

4. Calcium oxide reacts with the impurity silicon dioxide. Write the chemical equation for this chemical reaction.

Calcium carbonate - CaCO3

Calcium carbonate(s) calcium oxide(s) + carbon dioxide(g)

CaCO3(s) CaO(s) + CO2(g)

CaO(s) + SiO2(s) CaSiO3(l)