1. The Processing Steps to
Extract Light Metal from
Ore

2. Titanium Extraction
• The production of titanium beginning with a
report in 1887 by Milsen and Pettersen using
sodium ,which was optimised into commercial
Hunter process.
• Kroll process is invented by William J.Kroll in
Luxemburg around the mid 1930's.
• Extracted by Kroll process to obtain
commercially pure titanium metal.
• Rutile (TiO2) are the major ores of titanium.

3. • Process:
i)Conversion of titanium (IV) oxide,TiO2 into titanium (IV)
chloride,TiCl4
-The ore rutile(impure TiO2 ) is heated with chlorine and
coke at a temperature of about 900◦C.
TiO2 + 2Cl2 +2C TiCl4 + 2CO
-Titanium tetrachoride, TiCl4 and other metal chlorides
are formed because of other metal compounds in the
ore.
-Very pure liquid titanium (IV) chloride can be separated
from other chlorides by fractional distillation under an
argon or nitrogen atmosphere and it is stored in totally
dry tanks.
-As titanium is very reactive, oxygen must be kept out of the
reaction vessel so the reaction is done in an atmosphere of
argon.
-Besides that,titanium chloride is a typical covalent chloride
which fumes in moist air due to reaction with water to give
titanium (IV) oxide and fumes of hydrogen chloride.

4. ii)Reduction of Titanium (IV)chloride
A. Reduction by Sodium
 Used by UK.
 Titanium (IV) chloride is added to the reactor in which pure
sodium has been heated to about 550◦C.
 The temperature increased to about 1000 ◦C during the
reaction.
TiCl4 + 4Na Ti + 4 NaCl
 After the reaction is complete and everything has
cooled(several day in total) the mixture is crushed and
washed with dilute hydrochloric acid to remove the sodium
chloride.

5. B. Reduction by Magnesium
 Used in the rest of the world except UK.
 In a separator reactor,TiCl4 is reduced by liquid Magnesium
(15-20% excess) at 800-850 ◦C in a stainless steel retort to
ensure complete reduction.
TiCl4 + 2Mg (l) Ti(s) + 2 MgCl2(l)
 MgCl is removed from titanium by distillation under low
pressure at high temperature.

6.  MgCl2 can be further refined back to Mg by electrolysis.
 The resulting porous metallic titanium sponge is purified by
leaching or heated vacuum distillation.
 The sponge is jackhammered out ,crushed and processed
before it is melted in a consumable electrode vacuum arc
furnace.
 The melted ingot is allowed to solidify under vacuum.
 It is often remelted to remove inclusions and ensure
uniformity.
 This melting steps add to the cost of product.

7. Disadvantages
 Titanium is about 6 times as expensive as stainless steel.
 Titanium is expensive because it cannot extracted by
reducing the ore using carbon as a cheap reducing agent.
 Titanium form a carbide ,TiC , if heated with carbon, so pure
titanium cannot be obtain.
 Carbide also makes the titanium brittle.
 The reducing agents such as sodium and magnesium have
to be extracted from their ores by expensive process.

8. Process of Titanium Extraction

9.  Other technologies are competing with the
Kroll process:
 Electrolysis of a molten salt
• Problems with this process include "redox recycling," the
failure of the diaphragm, and dendritic deposition in the
electrolyte solution.
 Pyrometallurgical
• route that involves the reduction of an intermediate form
of titanium with aluminium has combines the advantages
of pyrometallurgy and a cheap reductant.

10. Aluminium
 Aluminium is the most widely used metal after iron.
 it is mostly used in an alloy with another metal . Eg: stainless steel.
 The primary ore of aluminum is bauxite, which forms when high
volumes of rain water move through soils.
 Typically the water dissolves and removes elements such as
sodium, potassium, and calcium, leaving altered soils called
laterites that contain significant amounts of highly insoluble metals
such as aluminum.
 Bauxite varies greatly in physical appearance, depending on its
composition and impurities. It ranges in colour from yellowish white
to gray or from pink to dark red or brown if high in iron oxides.

12. Extraction of Aluminium
 Aluminum is extracted from its oxide ore "Bauxite".
 Bauxite contains aluminium oxide, water, iron oxide and other
impurities.
 The purified dry ore, called alumina, is aluminium oxide ,Al2O3.
 The extraction of aluminum involves the following steps.
a) Purification of Bauxite
b) Electrolysis of Alumina (Aluminium Oxide)
c) Refining

13. Purifying the aluminium oxide - the
Bayer Process
 Bauxite contains two main impurities Fe2O3 and SiO2.
 These impurities must be removed in order to get good quality
aluminum. These impurities make the aluminum brittle and
liable to corrosion.
 The process occurs in two main steps.
 Firstly the aluminum ore is mixed with the sodium hydroxide in
which the oxides of aluminum and silicon will dissolve, but
other impurities will not.
 These impurities can then be removed by filtration.

14.  Carbon dioxide gas is then bubbled through the
remaining solution, which forms weak carbonic acid
neutralising the solution and causing the aluminum oxide
to precipitate, but leaving the silicon impurities in
solution.
 After filtration, and boiling to remove water, purified
aluminum oxide can be obtained.

15. Formation of pure aluminium oxide-
Electrolytic) Cell

16.  The aluminum oxide is mixed with cryolite (made of sodium fluoride
and aluminum fluoride) and then heated to about 980 °C to melt the
solids.
At the Cathode:
• The molten mixture is then electrolyzed with a very large current and
the aluminum ions are reduced to form aluminum metal which sinks
to the bottom of the cell.
Al3+ + 3e- ® Al
At the Anode:
• Oxygen gas is formed, where it reacts with the carbon the anode is
made from to give carbon dioxide gas.
2O2- ® O2 + 4e-
 More oxide is added as it is used up, and molten aluminum is
tapped off the bottom of the cell from time to time.

17. Diagram showing cell for Aluminium extraction:

18. Summary
• Aluminium is extracted from the ground in compounds, it
is the purified to alumina (aluminium oxide) in the Bayer
process
• The metal is finally obtained after electrolysis in a cryolite
solution.

19. Drawback of Aluminium Extraction:
 Aluminium extraction is expensive because the process is so
long and needs a lot of electrical energy.
 It generates large quantities of greenhouse gases. Emissions
come from extracting aluminum from bauxite and then
smelting the ore to get the aluminum.
 Life cycle assessment shows that aluminium production
produces more greenhouse gases than steel production.
 However when used in vehicles, aluminium’s lighter weight
leads to better fuel efficiency, and reduces greenhouse gas
emissions from transport.

20. Environmental problems
 Loss of landscape due to mining, processing and
transporting the bauxite.
 Noise and air pollution (greenhouse effect, acid rain)
involved in these operations.
 Atmospheric pollution from the various stages of
extraction.
 For example: carbon dioxide from the burning of the
anodes (greenhouse effect); carbon monoxide
(poisonous); fluorine (and fluorine compounds) lost
from the cryolite during the electrolysis process
(poisonous).
 Pollution caused by power generation (varying
depending on how the electricity is generated.)

21. Advantages of Aluminium:
 It is high strength to weight properties.
 Does not corrode in the same way as steel, because of
the strong thin layer of aluminium oxide on its surface.
This layer can be strengthened further by anodising the
aluminium.
 Light, and has high electrical conductivity.
 Can be recycled in a more efficient manner that is less
detrimental to the environment.

22. Recycling
 Saving of raw materials and particularly electrical energy by
not having to extract the aluminium from the bauxite.
 Recycling preserves limited resources and requires less
energy, so it causes less damage to the environment.
 Recycling aluminum also helps to decrease greenhouse gas
emissions, which pollute the air.
 Recycling aluminum conserves natural resources by
preventing the steady depletion of bauxite and other metal
ores.

23. WAYS TO IMPROVE ORE
EXTRACTION

24. Aluminium
• Indirect carbothermic reduction
• can be carried out using carbon and Al2O3,
• which forms an intermediate Al4C3 and this
can further yield aluminium metal at a
temperature of 1900–2000 °C.
• it requires less energy and yields less
CO2 than the Hall-Héroult process.

25. Cont..

26. Cont..
• The aluminum trichlorid precipitate is purifi
ed by dissolution and re-precipitation. The
final product is calcined to form alumina
• the alumina so produced has a higher
purity than alumina produced from bauxite
by the Bayer process.

27. Beryllium

28. • Sulphate extraction method.
• Acidic method for decomposing the ore.
• Based on the reactivity of beryll enhance by
the heat treatment.
• The resulting granular is readily to separated.
• Subsequently dewatered to 15wt% free water.
• The overall extraction are approximately
85wt%.

29. Lithium
• Fusion method
• powdered silicate mineral is fused
with CaCO3 and the fused mass is
extracted with HCl and filtered.
• The filtrate contains chlorides
Li, Al, Ca, Na and K whereas silicon is
removed as insoluble residue.
• The filtrate is evaporated to dryness and
the residue is extracted with pyridine in
which only LiCl dissolves.