1. GENERAL PRINCIPLES OF EXTRACTION OF METALS
CHAPTER 6
GENERAL PRINCIPLES OF EXTRACTION OF METALS

2. METALLURGY CONTENTS DEFINITION TYPES OF METALLURGY GENERAL METHODS
EXTRACTION OF ALUMINIUM
EXTRACTION OF IRON 2

3. Metallurgy
The extraction of metals from their ores and refining it is known as metallurgy 3

4. Types of metallurgy PYROMETALLURGY by heating the ore eg. Fe
ELECTROMETALLURGY
by passing electric current to the molten or aqueous solution of ore eg. Al
HYDROMETALLURGY
by dissolving the ore in a suitable reagent and precipitating the metal.eg. Au, Ag

5. IMPORTANT TERMS
MINERAL: the substance from which metal can be extracted.
ORE: the mineral from which metal can be extracted profitably and economically.
GANGUE: the earthy impurities found in ore.
FlUX: the substance added to ore to remove gangue particles.
SLAG: the fusible mass formed by the combination of gangue and flux.
GANGUE + FLUX SLAG

6. 6

7. ENRICHMENT/CONCENTRATION OF ORE
Process used for removal of the “GANGUE”
GANGUE – Soil, Sand and Earthy Impurities 7

8. ENRICHMENT/CONCENTRATION OF ORE
4 METHODS ----
GRAVITY SEPARATION METHOD.
FROTH FLOTATION METHOD
MAGNETIC SEPARATION METHOD
CHEMICAL METHOD(LEACHING)

9. Gravity separation 9

10. Froth Floatation 10

11. EXTRACTION OF METAL FROM CONCENTRATED ORE
CONVERSION OF ORE INTO ITS OXIDE FORM
Roasting
Calcination
CONVERSION OF OXIDE ORE INTO METAL
smelting

12. CONVERSION OF ORE INTO ITS OXIDE FORM
Conversion of concentrated ore into a more suitable form in REVERBIRATORY FURNACE
Roasting -- Heating the Sulphide ore in presence of air to form an Oxide ore
2ZnS+3O2  2ZnO + 2SO2
Calcination -- Heating the Carbonate ore in the absence of air to form an Oxide ore
ZnCO3 ZnO + CO2 12

13. Reduction(Smelting) Low in the reactivity series ----
Heating ---- e.g..2HgS + 3O2 2HgO +2SO2
2HgO(S) - 2Hg + O2 (g)
Middle in the reactivity series
Heating with C (Smelting)
ZnO + C --Zn + CO
High up in the reactivity series  Electrolytic reduction 13

14. REFINING OF METAL DIFFERENT METHODS FOR REFINING OF METALS ARE
Liquation
Distillation
Electrolytic refining

15. REFINING OF METAL ELECTROLYTIC REFINING
Used for Metals -Al, Cu, Zn, Sn, Ni, Ag..
CuSO4 + H2SO4 15

16. ALLOY
Alloy is defined as the homogeneous mixture of two or more metals/non-metals.

17. TYPES OS ALLOYS There are three types of alloys
1. FERROUS ALLOY: Fe is the main constituent
2. NON FERROUS ALLOY: Fe is not the main constituent
3. AMALGAM: Hg is the main constituent

18. PURPOSE OF MAKING ALLOYS
1. TO modify the colour
2. To increase the hardness of the metal
3. To increase the tensile strength of metal
4. To decrease the melting point of metal
5. To make the metal more resistance against corrosion

19. THANK YOU