- Iron is extracted from its ore, haematite, in a blast furnace using coke, limestone, and hot air. The limestone removes impurities and produces slag. - Iron rusts in the presence of oxygen and water to form iron(III) oxide. Rusting can be prevented by barriers like paint, grease, or sacrificial protection using more reactive metals like zinc. - Recycling metals saves limited metal resources and reduces costs and pollution compared to extracting virgin metals. However, recycling has costs and challenges like obtaining scrap metals.

2. Extraction of metals
(a) describe the ease of obtaining metals from their ores by relating the
elements to their positions in the reactivity series
Recycling of metals
(a) describe metal ores as a finite resource and hence the need to recycle
metals, e.g. the recycling of iron
(b) discuss the social, economic and environmental issues of recycling
metals
Iron
(a) describe and explain the essential reactions in the extraction of iron
using haematite, limestone and coke in the blast furnace
(b) describe the essential conditions for the corrosion (rusting) of iron as
the presence of oxygen and water; prevention of rusting can be achieved
by placing a barrier around the metal, e.g. painting; greasing; plastic
coating

3. Metals from Rocks
• The substances (elements or compounds) that make
up rocks are called minerals.

4. From Rocks to Metals
• A metal ore (usually oxides, sulfides, chlorides or
carbonates) is a rock from which a useful metal is
obtained.
• The process of getting metals from ores is called the
extraction of metals.
Bauxite – an aluminium ore

5. Occurrence of Metals
• Metal oxides – metal + oxygen
• Metal sulfides – metal + sulfur
• Metal carbonates – metal + carbon + oxygen
Some metal ores found in the Earth’s crust

6. Main minerals of metal ores

7. • Minerals are the elements or compounds
that make up rocks.
• A metal ore is a rock containing a mineral
from which a metal is extracted.
• Most minerals are the oxides, sulfides and
carbonates of metals. For example,
bauxite is an ore containing the
compound aluminium oxide.

8. ore
metal compound separated
from bits of sand & rocks
purified
metal compound
metal
extracted
metal chemically separated
from other elements

9. The Extraction of Metals
•The lower the
position of a metal
in the reactivity
series, the easier
it is to extract.
The reactivity series and the method of extracting metals

10. Extraction of the Least Reactive Metals
• The least reactive metals are at the bottom of the reactivity
series. Some are found as free metals.
• E.g. gold can be obtained by physical methods. The rocks are
collected and crushed to free the pieces of gold in them.
Rocks containing gold being extracted in a gold mine in Australia

11. • These metals occur as oxides and sulfides.
• The metal sulfides are heated in air to become metal
oxides.
• The metal is then obtained by heating the oxides with
carbon.
E.g.
Extraction of Less Reactive Metals
2ZnS(s) + 3O2(g) 2ZnO(s) + 2SO2
ZnO(s) + C(s) Zn(s) + CO(g)

12. Extraction of Very Reactive Metals
• Very reactive metals are difficult to extract.
• Most reactive metals are extracted by
decomposing their compounds with electricity.
This is called electrolysis.
2KCl(l) 2K(l) + Cl2(g)

13. • The method used to extract a metal depends
on the reactivity of the metal.
• Unreactive metals, such as gold, are often
found as free (uncombined) elements.
• Less reactive metals are extracted by heating
their oxides with carbon.
• Very reactive metals are extracted using
electrolysis.

14. Summary
Potassium
Sodium
Calcium
Magnesium
Aluminium
[Carbon]
Zinc
Iron
Tin
Lead
Copper
Silver
Gold
More
reactive
metals
Less
reactive
metals
Unreactive
metal
Electrolysis
Heating metal
oxide with
carbon
Heating the metal
oxide
Physical
methods

15. C h a p t e r 13 Recycling of Metals
Which Metals are Used Most?
• Iron is used in the largest amounts,
Extraction and Uses of Metals
followed by aluminium and copper.
Quantities of some
metals produced
T H E M E F O U R : P E R I O D I C I T Y

16. Extraction and Uses of Metals
C h a p t e r 13
• Only a limited amount of metal can be mined
from the Earth.
T H E M E F O U R : P E R I O D I C I T Y

17. Extraction and Uses of Metals
C h a p t e r 13
Conserving Our Resources of Metals:
Recycling
•One way of making metals last longer
is to use other materials in their
place.
• E.g. glass bottles for soft drinks are
used instead of metal cans.
• Metals can be recycled.
T H E M E F O U R : P E R I O D I C I T Y

18. C h a p t e r 13Conserving Our Resources of Metals:
Extraction and Uses of Metals
Recycling
T H E M E F O U R : P E R I O D I C I T Y
How aluminium cans are recycled

19. Benefits of Recycling
C h a p t e r 13
• Conserves the Earth’s finite resources of
metals.
• Saves cost of extracting new metals.
• Prevents land pollution caused by the
disposal of metals on landfills.
Extraction and Uses of Metals
Recycling prevents unsightly car dumps
T H E M E F O U R : P E R I O D I C I T Y
Recycled metal cans

20. Extraction and Uses of Metals
C h a p t e r 13
Some Problems with Recycling
•Metals are only recycled if it is
economical to do so.
•Can cause air pollution.
•The cost of separating metals from
waste can be high.
•Cost money to collect scrap metals.
• Difficult to persuade people to
deposit used materials in recycling
containers.
T H E M E F O U R : P E R I O D I C I T Y
Bins are provided for the collection
of aluminium cans for recycling.

21. Extraction and Uses of Metals
C h a p t e r 13
• There are limited amounts of metal ores in
the Earth.
• Recycling of metals has several advantages.
- It saves the limited amounts of metal ores.
- It saves the cost of extracting new metals
from ores.
- It can help the environment by preventing
land pollution.
• Recycling can cause air pollution and cost
money in transporting the scrap metals.
T H E M E F O U R : P E R I O D I C I T Y

22. Extraction of Iron
• Iron is mined from the ground
as iron ores.
• Haematite is one important
ore.
• Iron is extracted from the
oxide in a blast furnace.
• Iron ore, limestone and coke
are fed in at the top of the
furnace.
• Hot air is fed near the bottom
of the furnace.

24. Extraction and Uses of Metals
EC xh at pr ta ec r t1ion3 of Iron
• The following reactions
take place in the blast
furnace:
• Coke reacts with oxygen to
form carbon dioxide and heat.
C(s) + O2(g) CO2(g)
• Carbon dioxide reacts with
more coke to form carbon
monoxide.
CO2(g) + C(s) 2CO(g)
T H E M E F O U R : P E R I O D I C I T Y

25. C h a p t e r 13 • Carbon monoxide reacts with
Extraction and Uses of Metals
iron(III) oxide to produce molten
iron.
Fe2O3(s) + 3CO(g) 2Fe(l) + 3CO2(g)
• Limestone is decomposed by heat
to produce calcium oxide and
carbon dioxide.
CaCO3(s) CaO(s) + CO2(g)
• What is the purpose of adding
limestone into the blast furnace?
• To remove acidic impurities,
like sand, SiO2 .
T H E M E F O U R : P E R I O D I C I T Y

26. C h a p t e r 13
• Impurities such as silicon
Extraction and Uses of Metals
dioxide reacts with calcium
oxide to produce slag
(calcium silicate).
SiO2(s) + CaO(s) CaSiO3(l)
Acidic
impurities,
sand
T H E M E F O U R : P E R I O D I C I T Y

27. Extraction of iron
Hot waste gases such as carbon
monoxide, carbon dioxide and
nitrogen escape through the top
of the furnace.
Molten iron is collected.

28. • Iron(III) oxide, coke, limestone and air are
used in the extraction of iron.
• The iron is obtained by the reduction of
iron(III) oxide with carbon monoxide.
• Most impurities are removed by reaction
with calcium oxide (from limestone) to
produce slag.

29. Exercise Time:
The Conditions in the Blast Furnace
1. What is the role of coke in the blast furnace?
It acts as a reducing agent
2. What is the role of limestone in the blast furnace?
Limestone helps to remove acidic impurities
3. Which ore of iron is commonly used in the blast furnace?
Haematite
4. Why is it called a blast furnace?
Because hot air is ‘blasted into the furnace’
5. What do we call the layer of impurities that forms at the base of
the blast furnace above the liquid iron?
Slag

30. Exercise:
1. Which compound does haematite mainly consist of?
Iron (III) oxide
2. What is the chemical formula of this compound?
Fe2O3

31. Exercise
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?
Calcium carbonate - CaCO3
2. In the blast furnace this compound undergoes thermal
decomposition. Write a word equation for this reaction.
Calcium carbonate  calcium oxide + carbon dioxide
3. What is the chemical equation for this reaction?
CaCO3 (s)  CaO (s) + CO2 (g)
4. Calcium oxide reacts with the impurity silicon dioxide. Write the
chemical equation for this chemical reaction.
CaO (s) + SiO2 (s) CaSiO3 (l)

32. Questions :
1 a) Why is steel more suitable than iron in most uses ?
Iron is too malleable for most uses as the orderly layers of
atoms can slide over each other easily.
Steel is an alloy consisting of different sized atoms, which
disrupts the orderly arrangement of atoms, preventing the
layers from sliding over each other easily. Hence, steel is
harder and stronger for most uses.
b) Why is stainless steel popularly used for making cutlery ?
Stainless steel is corrosion resistant and does not rust.

33. 1c) Why is recycling aluminium easier than recycling scrap
iron?
Aluminium metal is very resistant to
corrosion. This is because aluminium reacts with
oxygen in the air to form a protective layer of
aluminium oxide. Iron has poor resistance to
corrosion and corrodes easily when exposed to air
and water. It Hence it is difficult to recycle.

34. Extraction and Uses of Metals
C h a p t e r 13 Rusting
•The corrosion of iron and steel is called rusting.
•The brown solid product formed during rusting is
called rust. It is mainly iron(III) oxide, Fe2O3.
T H E M E F O U R : P E R I O D I C I T Y

35. RC hu a ps tt ei rn1g 3 : Conditions for Rusting
Extraction and Uses of Metals
• Oxygen,
• Water, and
• Dissolved salt speeds up rusting.
T H E M E F O U R : P E R I O D I C I T Y

36. Extraction and Uses of Metals
PC hr ae p vt ee r n1ti3ng Rusting
• Surface Protection
1. Paint. e.g. street poles
2. Oil or grease e.g. machinery
Street poles are made of steel. These are protected from rusting by paint
T H E M E F O U R : P E R I O D I C I T Y

37. Extraction and Uses of Metals
C h a p t e r 13
• Surface Protection
Preventing Rusting
3. Plastic. e.g. metal clips
4. Metal plating. e.g. food cans
T H E M E F O U R : P E R I O D I C I T Y
Steel clips covered with a
layer of plastic.
Food cans are made of iron
covered with a thin layer of tin.
Most parts of the motorcycle is
plated with chromium.

38. Extraction and Uses of Metals
C h a p t e r 13
Ways to prevent rusting
Coating the object with a more reactive
metal that corrodes in place of iron. This
is called “sacrificial protection”.
E.g. zinc (galvanized iron)
T H E M E F O U R : P E R I O D I C I T Y

39. C h a p t e r 13
Sacrificial Protection
Extraction and Uses of Metals
• The sacrificial metal can
be bolted directly on
ship hull …..
T H E M E F O U R : P E R I O D I C I T Y
… or be connected
to the pipeline or
oil rig by
conducting
cables.

40. Extraction and Uses of Metals
C h a p t e r 13
Sacrificial Protection
How this work.. ?
• The more reactive metal corrodes in
place of iron, hence iron is spared
from rusting.
T H E M E F O U R : P E R I O D I C I T Y

41. Extraction and Uses of Metals
C h a p t e r 13
Sacrificial Protection
Advantages:
• Economical and most effective
protection.
• Minimal maintenance is required.
Disadvantages:
• The sacrificial metal must be replaced
before it all dissolves.
T H E M E F O U R : P E R I O D I C I T Y

42. Extraction and Uses of Metals
C h a p t e r 13
• Iron and steel rust in the presence of
water and oxygen.
• Rusting can be prevented by coating the
iron object with a layer of substance. This
can be paint, oil, grease or another metal.
It prevents air and water from reaching
the iron.
T H E M E F O U R : P E R I O D I C I T Y

43. C h a p t e r 13 Uses of Metals
Extraction and Uses of Metals
• The choice of one metal over another
depends on:
- Its physical properties
- Its chemical properties
- Its cost
Aluminium used in trains
T H E M E F O U R : P E R I O D I C I T Y

44. C h a p t e r 13 Uses of Metals
Extraction and Uses of Metals
T H E M E F O U R : P E R I O D I C I T Y

45. Extraction and Uses of Metals
C h a p t e r 13
T H E M E F O U R : P E R I O D I C I T Y