1. Metallurgy is the extraction of pure metals from their ore. It involves processes like concentration, isolation, and refining. 2. Metals are extracted through processes like calcination, roasting, and electrolysis depending on their reactivity. Highly reactive metals require electrolytic reduction while others can be reduced using carbon or other metals. 3. Alloys are mixtures of two or more metals that have different properties than the pure metals. Common alloys include steel, brass, and bronze. Alloys and other techniques like galvanization and anodization are used to prevent corrosion of metals.

1. METALLURGY

2. Occurrence of Metals
Occurrence of Metals
(It occurs in Earth’s curst,
sea water)
Minerals
Elements or compounds occurring naturally in Earth’s
crust.
Ores
Minerals that contain very high percentage of a
particular metal. These metals can be extracted
economically on large scale.
e.g. Bauxite → Aluminium. Haematite → Iron
Metallurgy – The field
of science dealing with
extraction of pure
metals from their ores.

3. Occurrence of Metals in Nature
Metal Reactivity Series Occurrence Ore Metallurgy
K
Most Reactive Combine State Electrolysis
Na
Ca
Mg
Al
Zn
Moderately
Reactive
Combine State Sulphide,
Oxide ores
Calcination,
Roasting
Fe
Pb
Cu
Least Reactive
Free and
Combine State
Carbonate
Ores
Roasting
Hg
Free State Sulphide or
Oxide Ore
Ag
Au
1.
2.
3.

4. Extraction of metals from their ores :-
Metals are extracted from their ores in three main steps. They are :-
i) Concentration of the ore (Enrichment of the ore).
ii) Isolation of the metal
iii) Refining (Purification of the metal).
Concentration of the ore :- It is the removal of gangue (impurities) from the ore
by different methods.

5. Extraction of Metals

6. Conversion of Ore to Metal Oxide
Calcination Roasting
It is done for Carbonate Ores It is done for Sulphide Ores
Heating of carbonate ores in absence
of oxygen
Heating of Sulphide ores in presence
of oxygen
CO2 gas is released and metal oxide
is obtained
SO2 gas is released and metal oxide
is obtained
ZnCO3 (s) →
Heat
ZnO (s) + CO2 (g) ZnS(s) + 3O2 →
Heat
2ZnO (s) + 2SO2(g)

7. 1. Extraction of Metals Low in Activity
Series
2Cu2O (s) + 2SO2 (g)
2HgO (s) → 2Hg (l) + O2 (g)
Cinnabar
Ore (HgS)
Mercuric
Oxide (HgO)
Mercury
Reduction (on
further heating)
Roasting
Heating
2HgS (s) + 3O2 (g) → 2HgO (s) + 2SO2 (g)
Heating
Copper
Copper
Sulphide
(Cu2S)
Roasting
Copper
Oxide
(Cu2O)
Reduction (on
further heating)
Heating
2Cu2S (s) + 3O2 (g) →
Heating
2Cu2O (s) + Cu2S → 6 Cu (s) + SO2 (g)

8. 2. Extraction of Metals in the Middle of Activity Series
ZnCO3 (s)
2ZnO (s) + C (s) → Zn (s) + CO2 (g)
2ZnO (s) + C (s)
Zinc
Sulphide
(ZnS)
Zinc Oxide
(ZnO)
Zinc
Reduction (on
heating with Coke)
Roasting
Heat
2ZnS (s) + 3O2 (g) → 2ZnO (s) + 2SO2 (g)
Heat
→ Zn (s) + CO2 (g)
Zinc Oxide
(ZnO)
Zinc
Reduction (on
heating with coke)
Zinc
Carbonate
(ZnCO3)
Calcination
Heat
→ 2ZnO (s) + 2SO2 (g)
Heat

9. Thermite Reaction
• Apart from using coke to reduce metal oxides to metals,
displacement reactions can also be used.
• Highly reactive metals such as Sodium, Calcium, Aluminium
are used as reducing agents and displace metals of lower
reactivity than them from the metal oxides.
• For example, when Manganese dioxide is heated with
Aluminium powder,Aluminium displaces Manganese as
follows.
3MnO2 (s) + 4Al (s) 3 Mn (l) + 2Al2O3 (s) + Heat
• These displacement reactions are highly exothermic that the
metals produced will be in molten state.
Fe2O3 (s) + 2Al (s) 2 Fe (l) + Al2O3 (s) + Heat
• This phenomenon is used to join railway tracks.

10. 3. Extraction of Metals in Top of Activity
series
Highly
Reactive
Metals
They have more affinity for
Oxygen than Carbon.
They cannot be obtained
from their compounds by
heating with carbon.
For e.g. Carbon cannot
reduce oxides of Sodium,
Magnesium, Calcium etc.
These metals are obtained
by electrolytic reduction.
At cathode
At anode
Na+ + e- → Na
Cl- → Cl + e-
Molten Chlorides
of Highly reactive
metals
Metals are
deposited at
cathode
Chlorine is
liberated at
anode
Electrolytic
Reduction

11. Electrolytic extraction of Na

12. Refining of Metals - Electrolysis
• A strip of impure metal (to be refined) is taken as anode.
• Pure metal (Small Strip) of same material is taken as Cathode.
• Electrolyte of same metal solution is used.
• When electric current is passed, pure metal is deposited at
Cathode.
• Impurities are collected at the bottom of anode (anode mud)

13. Corrosion
• Metals when left open in air gets corroded.
• Silver + Sulphur in air Silver Sulphide (black coat)
• Copper + Carbon dioxide in air Copper carbonate
(green coat)
• Iron + Air and Moisture Iron oxide (rust) (Brown flaky)

14. Prevention of Corrosion
• By applying paint
• By applying oil / grease
• Galvanizing a metal
• Anodizing a metal
• By making alloys
Coating of zinc on metal
Coating a layer of Aluminium
Oxide on Aluminium

15. Alloys
• An alloy is a homogeneous mixture of two or more metals, or a metal and a nonmetal.
• It is prepared by first melting the primary metal, and then, dissolving the other elements
in it in definite proportions. It is then cooled to room temperature.
• E.g. Steel - (Fe + Ni + Cr)
Brass - (Cu + Zn)
Bronze – (Cu + Sn)
Solder – (Pb + Sn)
Notes-:
• If one of the metals is mercury, then the alloy is known as an amalgam.
• The electrical conductivity and melting point of an alloy is less than that of pure metals.
For example, brass and bronze alloys of copper are not good conductors of electricity
where as copper is a very good conductors.
• Solder, an alloy of lead and tin, has a low melting point and is used for welding
electrical wires together (soldering).

16. Activity – Rusting of Iron Nails
• Take three test tubes A, B, C and place clean Iron
nails.
Test tube A – water
Test tube B – Distilled water
+ 1 ml of oil
Test tube C – anhydrous
Calcium chloride

17. Activity – Rusting of Iron Nails
• Leave these test tubes for a few days and then observe.
Observation:
 Nails in Test tube A rusts.
 Iron Nails in Test tubes B & C does not rust
Reason:
 Nails in Test tube A  exposed to air and water
 Nails in Test Tube B  does not get exposed to air
due to layer of oil
 Nails in Test Tube C  Does not get both air and
water
Conclusion: Both air and water are required for iron nails
to form rust.