To lear about Metals and pruifications

2. Occurrence of Metals
Generally, metals occur in nature as their compound
(except less active metals like Cu, Ag, Au etc. which
found native state).
The metallic compounds
that in the earth are called minerals. The minerals
from which metals can be extracted readily and
profitably are called ores.

3. Types of ores
Ores are found in the form of oxides, sulphate
carbonates, sulphates, chlorides and silicates.
Ore Example
 Oxide ore Al,Fe, Ti
 Sulphide ores Cu, Zn, Hg
 Carbonate ores Mg, Zn Ca
 Sulhate ores Mg, Ca, Ba
 Chloride ores Na, Mg, Ag
 Silicate ores Mg, Al

4. Flux
The earthy impurity or gangue is generally infusible.
But it can be converted into a fusible mass called
slag by the addition of a compound called flux.
Being light. The slag floats on the molten metal and
can skimmed off.
Gangue + Flux --------> Slag
The nature of flux used depends upon
the nature of the impurity to be
removed. A basic flux
An acidic flux

5. Refining of Metal
 Vapour phase refining
Ultra-pure metals like titanium, zirconium,
vanadium, thorium etc. are obtained by this
method.
 Electrolytic refining
 This is the most convement method for refining metals like
copper, silver, gold, tin, chromium and nickel. By electrolytic
refining 99.9 percent pure metal can be obtained.
 Zone refining
 Pure metals (with impurities < 10-9atom percent) to obtained
by the zone refining technique.

6. EXTRACTION OF METALS
TITANIUM
 Occurrence
 Titanium does not occur fee in nature. In the
combined state, it occurs in sands and rocks. Its main
ores are:
 Rutile TiO2
 Ilmenite FeTiO3

7. Extraction
Titanium metal is commercially
obtained from ilmenite ore. The
extraction consists of three steps:
 Purification of Ti (van Arkel method)
 Reduction of TiCl4 (kroll’s process)
 Preparation of TiCl4 (Chlorination process)
 Modern method
 Conversion of the ore in to TiO2
 Reduction of TiO2 (Alumino-thermite process)

8. Uses
As metal
 Titanium cathode is used in special photoelectric
cells.
 Pure titanium metal is used in making incandescent
titament.
As alloys
 Alloys of Ti with Co and Ni are used in making
filaments in vacuum tubes in place of Pt-Ir alloy
which is very costly.
 Ferrotitanium, an alloy of Ti with Fe is used as
scavenger in steel industry. It removes adsorbed
oxygen and nitrogen.

9. THORIUM
Occurrence
 Thorium is widely distributed in nature is
association with uranium and rare earths (mainly La
and Ce). Its chief ores are:
 Thorite ThO2. SiO2
 Thorianite ThO2.UO2.SiO2
 Monazite Th3(PO4)4. (La.Co)PO4

10. Extraction
 Preparation of Thoria
 Purification of Thoria
 Conversion of ThO2 to ThCl4
 Reduction of ThCl4
 Purification of Th (Van Arkel method)

11. Uses
As metal
Thorium is a redicative element. Bombardment of
thorium with thermal neutrons leads to the formation
of u233 isotope.
Equation
As alloys
 Thorium alloys are used as reducing agents in
metallurgy.

12. Molybdenum
 OCCURRENCE
 Molybdenum never occurs in native state. Its
chief ores are:
 Molybdenite MoS2
 Wulfenite PbMoO4
 Molybdite Fe2O3 3MoO3 7.5 H2O

13. EXTRACTION
 Concentration
 concentrated by froth flontation process.
 Roasting
 a current of air in a reverberatory furnace when crude MoO3 is
formed.
 Purification of MoO3:
 The crude MoO3 is boiled with excess of concentrated
ammonia when ammonium molybdate is formed
 Metallurgy:
 Molybdenum inetal is obtained by the reduction of pure
MoO3 by hydrogen at 11000C.
 Refining:
 The metal is heated in a current of carbon monoxide at 2000C
under pressure.

14. Uses
As metal
 Molybdenum metal is used as an anticathode in X-ray
tubes.
 With tungsten, it is used as thermocouple for high
temperature measurements.
 It is used as a support for tungsten filament incandescent
bulbs.
As alloys
 Molybdenum steels are used for making rifle barrel, high
speed lathe tools etc.
 Stainless steel containing 2-4% molybdenum is corrosion
resistant and used to make surgical instruments.

15. COBALT
 Occurrence: Cobalt occurs mainly as arsenides and
sulphides. The principal ores are:
 Smaltite (Co, Ni, Fe) As2
 Cobaltite (Co, Fe, As) S

16. Extraction
 Concentration
 Roasting
 Smelting
 Roasting the spies with NaCl
 Removal of Cu and Fe
 Separation of Ni from Co
 Formation of Co3O4
 Reduction of Co3O4

17. Uses
 In electroplating
 For making blue glasses, tiles and enamels
 For the manufacture of special steels.
 Stellites (55% Co, 15% Cr, 22% W and 5% Mo). It is
used for making cutting tools, lathe tools and surgical
instruments.
 Cochrome (60% Co, 14% Cr and 24% Fe). It is used for
making resistance wires.

18. PLATINUM
 Occurrence:Platinum mostly occurs in the native
state.
 The metal is obtained as a by-producing during the
extraction of nickel by Mond’s process.
 The production of platinum metal from the Mond’s
process residue involves two steps:
 Preparation of the platinum metals concentrate
 Separation of platinum form the concentrate.

19. Separation of platinum from the concentrate
 Treatment of concentrate with Aqua-regia:
 Separation of Gold:
 Recovery of Pt:
 Separation of Pd:
Uses
As metal
 Platinum metal resists corrosion and hence used in making
laboratory apparatus such as erucibles, basins, boats, dishes
and incinerating pans.
As alloys
 Platinum is a silvery white noble metal. A alloy of platinum
with irridium or palladium has been used in jewellery.
 An alloy of platinum with iridium is used in fountain pen
nibs.