Ores and minerals

1. CONTENT:CONTENT:
ORES AND MINERALSORES AND MINERALS

2. EXTRACTION EXTRACTION
OF MINERALSOF MINERALS

3. Very reactive metalsVery reactive metals can only be extracted from their ores by can only be extracted from their ores by
electrolysis such as K, Na, Ca, Mg, and Al.electrolysis such as K, Na, Ca, Mg, and Al.
Pb is less reactive metal but extraction through electrolysis.Pb is less reactive metal but extraction through electrolysis.
Discussion on the extraction of the following:Discussion on the extraction of the following:
i. Aluminium from molten aluminium oxide (Bauxite) i. Aluminium from molten aluminium oxide (Bauxite)
ii. Sodium from molten sodium chloride (Halite).ii. Sodium from molten sodium chloride (Halite).
iii. Iron from iron (III) oxide Feiii. Iron from iron (III) oxide Fe
22OO
33, (Hematite)., (Hematite).
iv. Lead from Lead (II) sulphid (Galena).iv. Lead from Lead (II) sulphid (Galena).
v. Tin@Stanum from Tin (IV) Oxide SnOv. Tin@Stanum from Tin (IV) Oxide SnO
22 (Cassiterite). (Cassiterite).

4. K
Na Very reactive metals
Ca Their ores require strong reduction which is
Mg done through electrolysis of molten ores
Al
Carbon
Zn Fairly reactive metals
Fe Their ores can be reduced by heating
Sn strongly with carbon
Pb
Hydrogen
Cu Their ores can easily be reduced by heating
Hg directly in air
Ag Less reactive metal
Au They exist as free metals in nature

5. EXTRACTION OF EXTRACTION OF
TIN@STANUM, SnTIN@STANUM, Sn

6. Roasted
Roasted
Heated with
coke and
limestone in
blast furnace
Heated with
coke and
limestone in
blast furnaceMolten tin is
draw n off and
moulded
Molten tin is
drawn off and
moulded
Tin block
CassiteriteC R S N : A D O M A D
I O N : A
Crushed and
washedL X F E O E T F M D E F D
V F M V : M E R O E : D E : D
F R :
Flotation to
concentrate the
ore
Flow-chart below summarises the extraction of tin / stanum

7. The main ore of tin is cassiterite which contains tin The main ore of tin is cassiterite which contains tin
(IV) oxide, SnO(IV) oxide, SnO
22. .
The ore is first crushed, grounded and washed.The ore is first crushed, grounded and washed.
Then the ore is concentrated by mixing it with oil Then the ore is concentrated by mixing it with oil
and water. In this flotation method, the tin and water. In this flotation method, the tin
minerals, which are less dense, are trapped in the minerals, which are less dense, are trapped in the
floating form. floating form.
The impurities such as soil and sand which are The impurities such as soil and sand which are
denser, sink to the bottom.denser, sink to the bottom.

8. The concentrated ore is then roasted in the The concentrated ore is then roasted in the
air. This converts the sulphide of tin to air. This converts the sulphide of tin to
oxide. At the same time, impurities such as oxide. At the same time, impurities such as
sulphur and oil are burnt off.sulphur and oil are burnt off.
The reduction of tin (IV) oxide to extracted The reduction of tin (IV) oxide to extracted
tin takes place in the blast furnace by tin takes place in the blast furnace by
carbon monoxide and coke.carbon monoxide and coke.
SnOSnO
22 + 2CO → Sn + 2CO + 2CO → Sn + 2CO
22
SnOSnO
22 + 2C → Sn + 2CO + 2C → Sn + 2CO
SnOSnO
22 + C → Sn + CO + C → Sn + CO
22
The molten tin is drained off into moulds to The molten tin is drained off into moulds to
become blocks.become blocks.

9. Photograph shows extraction of stanum in
factory.

10. Properties of Stanum, SnProperties of Stanum, Sn
–Melting point 232Melting point 232
oo
CC
–Boiling point 2603Boiling point 2603
oo
CC
–Silvery in colourSilvery in colour
–Highly ductile and malleable at Highly ductile and malleable at
temperature 100temperature 100
oo
CC

11. Uses of Stanum, Sn in daily lifeUses of Stanum, Sn in daily life
Stanum/tin is widely used in alloy making for Stanum/tin is widely used in alloy making for
example:example:
i.i.Produce bronze as alloy (70% Cu + 30% Sn).Produce bronze as alloy (70% Cu + 30% Sn).

ii.ii.Industrial processes as in the form of:Industrial processes as in the form of:
Tinplate, pewter (96% Sn + 3 % Cu and 1% Sb) and Tinplate, pewter (96% Sn + 3 % Cu and 1% Sb) and
solders (70% Pb + 30% Sn)solders (70% Pb + 30% Sn)
iii. In aerospace industry ( Stanum +Titanium ).iii. In aerospace industry ( Stanum +Titanium ).
iv. Ingredients in some insecticides.iv. Ingredients in some insecticides.

12. EXTRACTION OF EXTRACTION OF
ALUMINIUMALUMINIUM

13. Aluminium is extracted from its ore, bauxite which Aluminium is extracted from its ore, bauxite which
contains aluminium oxide Alcontains aluminium oxide Al
22OO
33 but not from but not from
aluminium chloride because aluminium chloride aluminium chloride because aluminium chloride
does not melt when heated.does not melt when heated.
Aluminium oxide is mixed with cryolite, NaAluminium oxide is mixed with cryolite, Na
33AlFAlF
66
to lower the melting point of aluminium oxide from to lower the melting point of aluminium oxide from
20452045
oo
C to about 900C to about 900
oo
CC. .
4000A current is used to keep the temperature of 4000A current is used to keep the temperature of
the electrolysis cell at 900the electrolysis cell at 900
oo
C.C.
Block of carbon act as anodesBlock of carbon act as anodes
Carbon lining act as cathode.Carbon lining act as cathode.

14. EXTRACTION OF ALUMINIUM
Block carbon
Carbon lining

15. CCathodeathode, the aluminium ions are discharged to , the aluminium ions are discharged to
form aluminium metal.form aluminium metal.
AlAl
3+3+
+ 3e → Al + 3e → Al
AAnodenode, the oxide ions are discharged to form , the oxide ions are discharged to form
oxygen gas.oxygen gas.
2O2O
2-2-
→ O → O
22 + 4e + 4e
--
The overall chemical reaction is:The overall chemical reaction is:
2Al2Al
22OO
33 → 4Al + 3O → 4Al + 3O
22
The oxygen liberated at the anode will react The oxygen liberated at the anode will react
with the carbon electrode to produce carbon with the carbon electrode to produce carbon
dioxide gas.dioxide gas.
The anode is corroded slowly and must be The anode is corroded slowly and must be
replaced form time to time.replaced form time to time.

16. Physical Properties of AluminiumPhysical Properties of Aluminium
1) Is strong.1) Is strong.
2) 2) malleablemalleable . .
3) Low 3) Low densitydensity..
4) Resistant to 4) Resistant to corrosioncorrosion because the presence because the presence
of an impervious oxide layer on the surface ofof an impervious oxide layer on the surface of
aluminium.aluminium.
5) G5) Good conductorood conductor of heat and electricity. of heat and electricity.
6) Can be polished to give a highly reflective6) Can be polished to give a highly reflective
surface.surface.

17. Chemical properties of aluminiumChemical properties of aluminium
Reaction with non-metallic elementsReaction with non-metallic elements
Aluminium reacts directly with non-metallic elements Aluminium reacts directly with non-metallic elements
when heated.when heated.
4Al + 3O4Al + 3O
22 2Al2Al
22OO
33
2Al + 3S 2Al + 3S AlAl
22SS
33
2Al + N2Al + N
22 2AlN2AlN
4Al + 3C 4Al + 3C AlAl
44CC
33
2Al + 3Cl2Al + 3Cl
22 AlAl
22ClCl
66

18. Chemical properties of AluminiumChemical properties of Aluminium
React with hydrochloric acid and sulphuric React with hydrochloric acid and sulphuric
acidacid
Aluminium react with dilute hydrochloric acid to Aluminium react with dilute hydrochloric acid to
liberate hydrogen gas. The reaction is more liberate hydrogen gas. The reaction is more
vigorous as the acid becomes hotter and more vigorous as the acid becomes hotter and more
concentrated.concentrated.
2Al + 6HCl → 2AlCl2Al + 6HCl → 2AlCl
33 + 3H + 3H
22
However, with hot dilute or concentrated sulphuric However, with hot dilute or concentrated sulphuric
(VI) acid, sulphur dioxide gas is liberated(VI) acid, sulphur dioxide gas is liberated
2Al + 6H2Al + 6H
22SOSO
44 → Al → Al
22(SO(SO
44))
33 + 3SO + 3SO
22 + 6H + 6H
22OO

19. Chemical properties of aluminiumChemical properties of aluminium
Reaction with nitric (V) acidReaction with nitric (V) acid
No reactionNo reaction because nitric acid makes because nitric acid makes
aluminium passive by increasing the aluminium passive by increasing the
thickness of the oxide layer on aluminium thickness of the oxide layer on aluminium
surface.surface.

20. Chemical properties of aluminiumChemical properties of aluminium
Reaction with alkalisReaction with alkalis
When dilute sodium hydroxide is added to aluminium at When dilute sodium hydroxide is added to aluminium at
room temperature, a violent reaction occur with the room temperature, a violent reaction occur with the
evolution of hydrogen gas. The reaction is highly evolution of hydrogen gas. The reaction is highly
exothermic and is accelerated by heat.exothermic and is accelerated by heat.
2Al + 2NaOH + 6H2Al + 2NaOH + 6H
22O → 2NaAl(OH) + 3HO → 2NaAl(OH) + 3H
22

21. Uses of AluminiumUses of Aluminium
Low density and strength make it ideal forLow density and strength make it ideal for
construction of aircraft, lightweight vehicles, and construction of aircraft, lightweight vehicles, and
ladders.ladders.
An alloy of aluminium called An alloy of aluminium called duraluminduralumin and and
magnaliummagnalium is often used instead of pure is often used instead of pure
aluminium because of its improved properties.aluminium because of its improved properties.
Easy shaping and corrosion resistance make it a Easy shaping and corrosion resistance make it a
good material for drink cans and roofing good material for drink cans and roofing
materials materials

22. EXTRACTION OF IRONEXTRACTION OF IRON

23. Two important ores used in extracting iron are Two important ores used in extracting iron are
hematite, Fehematite, Fe
22OO
33 and magnetite, Fe and magnetite, Fe
33OO
44..
First, these ores undergo several processes to First, these ores undergo several processes to
remove the impurities.remove the impurities.
Then, the concentrated ores are reduced by Then, the concentrated ores are reduced by
carbon in the form of coke in a very large and carbon in the form of coke in a very large and
hot furnace called blast furnace. Its hot furnace called blast furnace. Its
temperature can reach up 2000temperature can reach up 2000
oo
C.C.

25. A small charge is introduced from the A small charge is introduced from the
top of the blast furnace at intervals of top of the blast furnace at intervals of
10 to 15 minutes. 10 to 15 minutes.
The charge consists of concentrated The charge consists of concentrated
iron ores, coke and limestone.iron ores, coke and limestone.

26. Blast of extremely hot air are pumped through the furnace via the
bottom. The oxygen in the hot air reacts with coke to form
carbon dioxide .
C + O
2
→ CO
2
Blast of extremely hot air are pumped through the furnace via the
bottom. The oxygen in the hot air reacts with coke to form
carbon dioxide .
C + O
2
→ CO
2
Excess carbon reacts with carbon dioxide producing carbon
monoxide ( the main reducing agent) in the furnace.
C + CO
2
→ 2CO
Excess carbon reacts with carbon dioxide producing carbon
monoxide ( the main reducing agent) in the furnace.
C + CO
2
→ 2CO
Carbon monoxide and carbon reduce the iron oxides to iron.
Fe
2
O
3
+ 3CO → 2Fe + 3CO
2
2Fe
2
O
3
+ 3C → 4 Fe + 3CO
2
Fe
3
O
4
+ 4CO → 3Fe + 4CO
2
Fe
3
O
4
+ 2C → 3Fe + 2CO
2
Carbon monoxide and carbon reduce the iron oxides to iron.
Fe
2
O
3
+ 3CO → 2Fe + 3CO
2
2Fe
2
O
3
+ 3C → 4 Fe + 3CO
2
Fe
3
O
4
+ 4CO → 3Fe + 4CO
2
Fe
3
O
4
+ 2C → 3Fe + 2CO
2
The following flow chart outlines the reduction of the iron ores The following flow chart outlines the reduction of the iron ores

27. The molten iron is collected at the bottom of the The molten iron is collected at the bottom of the
furnace. It is drained off periodically into moulds furnace. It is drained off periodically into moulds
and is allowed to cool. The product known as cast and is allowed to cool. The product known as cast
iron.iron.
At the same time, the intense heat in the blast At the same time, the intense heat in the blast
furnace causes the limestone to decomposes.furnace causes the limestone to decomposes.
CaCOCaCO
33 → CaO + CO → CaO + CO
22
The calcium oxide then reacts with the impurities The calcium oxide then reacts with the impurities
in the ores, which consist mostly of sand, SiOin the ores, which consist mostly of sand, SiO
22 to to
form calcium silicate, CaSiOform calcium silicate, CaSiO
33 or slag. or slag.
CaO + SiOCaO + SiO
22 → CaSiO → CaSiO
33(l)- slag(l)- slag

28. Properties and Uses of IronProperties and Uses of Iron
Cast iron is very brittle (it cracks easily) Cast iron is very brittle (it cracks easily) butbut it it
has a greater resistance to corrosion than either has a greater resistance to corrosion than either
pure iron or pure iron or steelsteel..
Cast iron is used for manhole covers on roads Cast iron is used for manhole covers on roads
and pavements and as engine blocks for and pavements and as engine blocks for petrolpetrol
and and dieseldiesel engines. engines.
Pure iron is called wrought iron. Wrought iron is Pure iron is called wrought iron. Wrought iron is
malleablemalleable and is mainly used in ornamental work and is mainly used in ornamental work
for gates.for gates.
React as catalyst in the Haber Process.React as catalyst in the Haber Process.

29. EXTRACTION OF LEAD, PbEXTRACTION OF LEAD, Pb

30. Main source of Lead metal is the ore Main source of Lead metal is the ore
galena.galena.
Lead is a soft metal.Lead is a soft metal.
Lead bromide must be heated until it is Lead bromide must be heated until it is
molten before it will conduct electricity.molten before it will conduct electricity.
Electrolysis separates the molten ionic Electrolysis separates the molten ionic
compound into its elements compound into its elements

31. EXTRACTION OF LEAD THROUGH
ELECTROLYSIS

32. The reactions at each electrode are called half The reactions at each electrode are called half
equations.equations.
The half equations are written so that the same The half equations are written so that the same
number of electrons occurs in each equation.number of electrons occurs in each equation.
PbPb
2+2+
+ 2e- → Pb + 2e- → Pb (cathode) (cathode)
2Br2Br
--
→ Br → Br
2 2 + 2e+ 2e (anode ) (anode )
Lead ions gain electrons (reduction) to form lead Lead ions gain electrons (reduction) to form lead
atoms.atoms.
Bromide ions lose electrons (oxidation) to form Bromide ions lose electrons (oxidation) to form
bromine atoms.bromine atoms.
The bromine atoms combine to form molecules of The bromine atoms combine to form molecules of
bromine gas.bromine gas.
The overall reaction isThe overall reaction is
PbBrPbBr
22(l) → Pb(s) + Br(l) → Pb(s) + Br
22(g)(g)

33. Properties of Lead, PbProperties of Lead, Pb
–Melting point 327.4Melting point 327.4
oo
CC
–boiling point 1750boiling point 1750
oo
CC
–Soft metal.Soft metal.
–Easily Easily malleabilitymalleability or can be shaped. or can be shaped.
–Grey in colour.Grey in colour.
–Resistance to corrosion.Resistance to corrosion.

34. THANK YOUTHANK YOU