Non Ferrous Metal

1. BUILDING CONSTRUCTION MATERIALS
Non-Ferrous Metals

2. Introduction
• Although Iron & Steel are the most
commonly used materials in building and
engineering industries many non ferrous
metals & alloys have been used with great
advantage in both this fields.
• However, non ferrous metals are costlier
and used only when they satisfy certain
specific requirement.

3. Introduction

4. Non-Ferrous Metals
Special Advantages over ferrous metals
(a) Civil Engineering Construction – Aluminium & its
alloys alternative material to steel in some special
engineering construction
Wrought aluminium alloys are – (i) Economical
(ii) Resistance to corrosion
(iii) Light in weight
• In the construction of bridges and roofs in situations where
not much strength is required, these alloys have been used.
• In these situations, weight saving is about 50%

5. Non-Ferrous Metals

6. Non-Ferrous Metals
(b) Engineering Industries – Copper, zinc, nickel and chromium
in their pure and alloyed forms have been used as materials in
situations where
(i) High tensile strength is required at elevated temperatures
(ii) High ductility and malleability are required (e.g. screening,
staple, belt, cable, weld, catheter)
(iii) High resistance to heat is required (e.g. aerospace and
petrochemical applications)
(iv) High electrical conductivity is the desired property ( e.g.
wire-wound resistors, rheostats, potentiometers, and shunts.)
(v) Alloys are also used as thermostat metals, radio and
electronic devices, precision devises in aircraft controls,
telecommunications, automotive applications

7. Non-Ferrous Metals

8. ALUMINIUM
Aluminium is very common component 8% of the crust of the earth
• Common ore of aluminium – Bauxite (Al2O3.nH2O)
• First recovered in year 1825 as a metal
• Impurities – oxide, silica, clay, titanium oxide
• Stages of manufacture of aluminium from Bauxite:
Stage 1 – Bauxite is purified from all impurities as silica, titania and
iron and a pure oxide of aluminium is obtained
• To achieve this, two processes are there:
• Bayers Process – powdered ore is treated with sodium hydroxide
solution
• Serpak’s Process – powder is heated with coke at 1800⁰C
• in an atmosphere of nitrogen

9. ALUMINIUM

10. Flow Diagram For
Extraction Of Aluminium

11. Aluminium
Stage II – From the alumina as obtained above, metallic aluminium
is prepared by the Electrolysis process.
• Electrolysis is carried out in a huge electrolytic cell – Hall Heroult
Cell The cell is lined with carbon which acts as a cathode A bath
of alumina dissolved in cryolite (Na3 AlF6) is put in this cell which
acts as an electrolyte. A set of carbon rods are hung down in the
solution which act as anode.
• Electric current is passed through the solution. When temperature
of 953⁰ C is reached, the solution breaks into aluminium and
oxygen . Aluminium gets deposited in the molten form at the
bottom of tank and removed at regular intervals. Impurities get
deposited on the anodes as anode mud.
• Aluminium as obtained above has a purity of 99% and further
electrolysis make it 100% pure.

12. Aluminium

13. Aluminium

14. Properties
• White Metal And Shows Brilliant Lustre When Fresh.
• Lightest Among All Industrial Metals (Except Magnesium And
Beryllium) Having A Specific Gravity Of Only 2.7
• Low Melting Point - 650 ⁰ C, High Boiling Point - 2057 ⁰ C
• High Electrical And Thermal Conductivities
• Tensile Strength – 900 Kg/Cm2 And Can Be Improved To 1600 Kg/Cm2
By Hard-rolling Method
• Very Ductile And Can Be Transformed Into Any Shape
• Cast Into Any Shape By Any Method Of Casting E.G. Die Casting, Chill
Casting
• High Resistant To Corrosion. When Exposed To Moist Air, Aluminium
Forms A Thin Film Of Oxide At Top Which Is Impervious To Air Or
Moisture And Saves Metal From Further Corrosion.
• Forms Excellent Alloys With Number Of Metals Such As Copper,
Magnesium, Silicon, Zinc, Copper, Nickel, Chromium, Manganese

15. Properties

16. Properties

17. Application Of Aluminium As Engineering
Material
• Structural Engineering – frames and railing and roofing material
• Buildings – doors, windows, gates, water reservoirs, ventilating & heating
ducts
• Aircraft industry – as an alloy, super duralumin
• Railway – for fabrication of railway wagons and other body products
• Automobile Industry – for fabrication of bodies of trucks and buses
• Electrical Industry – as an economical conducting material, for overhead
transmission from generating to distribution stations
• Chemical and Food Processing Industry – for making aluminium tanks,
condensers, heat exchangers, containers, aluminium foil
• Cooking Utensils – due to excellent thermal conductivity, it can be used
for making cooking vessels and cooking ranges
• Nuclear Energy Projects – some aluminium alloys are considerably
resistant to nuclear radiation, so used as sheathing materials for uranium
rods

18. Application Of Aluminium As Engineering
Material

19. Anodizing
• Process of making metallic aluminium durable by giving a thin oxide
coating
• In electroplating cell - aluminium as anode and lead as cathode
• Electrolyte consists of dilute sulphuric acid, chromic acid or
phosphoric acid with some selected additives
• Electric current is passed through the circuit, a small thickness of
aluminium part gets converted to aluminium oxide (Al2O3), which is
exceptionally hard and resistant to corrosion
• Aluminium oxide coating of less than 1 mm
• Anodized coatings are porous, so it is dipped in hot water with or without
dyes to seal these pores for better protective covering

20. Anodizing

21. Copper
• Metallic Copper and its various alloys have
been used in engineering industries and
other applications. This is because of a
combination of some very useful properties
shown by this metal and its alloy.
• Among these properties following are more
important.

22. Copper

23. Copper
Following are more Important Properties;
• The metal is very malleable and ductile so
that it can be given any desired shape.
• The metal has a very high electrical
conductivity.
• It forms an Excellent Allows
• It has good resistance against corrosion.

24. Copper

25. Copper
Sulphide ores: Chalcopyrite (Cu Fe S2) – Cu-34.5% and
Chalcocite (Cu2 S) – Cu-79.8%
Oxide ores: Cuprite (Cu2 O) – Cu-88.8%
Manufacture process:
Concentration of the ores: Ores are contaminated with impurities,
called gangue minerals.
• The concentration of copper ore is increased by the process of
Froth flotation – ore is crushed and immersed in a bath containing
water and oil. Air is blown in the bath which rises the oily froth
above the layer of water.
• Most of the copper is concentrated to the extent of 90%
Roasting of the ores: Heating of ore in a suitable furnace to remove
volatile impurities such as sulphur. Ore is crushed to fine powder
and then heated in a current of air in a reverberatory furnace

26. Copper

27. Copper
Smelting: Reverberatory furnace or Blast furnace
• Heating the roasted ore at very high temperature (melting temperature)
in presence of air, coke and silica
• Iron in the ore combines with silica and form a slag
• Copper gets oxidized and sinks below as matte
Converting: Recovery of copper from the matte
• Matte is treated in Bessemer converter
• Air is blown through converter which serves to oxidize
• both iron and a part of copper of the matte
• Iron oxide reacts with silica and forms slag, copper oxide reacts with
sulphide thereby liberating metallic copper (Blister copper)
• 2FeS + 3O2 = 2FeO + 2SO2
• 2Cu2S + 3O2 = 2Cu2O + 2SO2
• 2Cu2O + 2Cu2S = 8Cu + SO2

28. Copper

29. Copper
Refining: Electrolytic method
• Blister copper is first cast into anode plates, pure
copper as cathode plates
• Copper sulphate solution as electrolyte
• On passing current, copper from anode is corroded
and deposited on pure copper cathode where from it
is removed periodically
• Purity is around 99.95% by this process

30. Copper

31. COPPER

32. Copper
Properties:
• It has Reddish colour, bright lustre
• It is Highly malleable, ductile
• If copper is heated to red heat and cooled slowly it becomes
brittle; but if cooled rapidly it becomes soft, malleable, ductile.
The brittleness is due to the coarsely crystalline structure that
developed during slow cooling.
• It has Melting point of 1083 ⁰C, boiling point 2505 ⁰C, specific
gravity 8.93
• Copper has Very high electrical conductivity
• Resistant to corrosion
• Excellent joining properties by welding, soldering, riveting
• Forms excellent alloys like bronze and gun metal
• Tensile strength – 300 to 470 MN/m2.

33. Copper

34. Copper
Applications:
• Electrical Industry (due to high electrical conductivity) – manufacture of
generators, motors, switchboards, communication equipment, wires for
transmission of sound and electricity
• Chemical Industry (due to resistant to corrosion and high thermal
conductivity) – chemical plants, copper tanks and utensils for food
industries, milk processing and refining industries good quality copper
is used for manufacture of copper compounds like copper sulphate, copper
cyanide, copper oxide etc. Copper powder has been used extensively in
powder metallurgy
• Alloys of Copper – Forms very useful alloys with metallic zinc and
metallic tin, which is go under the common names of Brasses and
Bronzes respectively

35. Copper

36. Zinc
Manufacture: Chief ore – sphalerite (Zn S : zinc : 67%)
• Other source minerals – Smithsonite (ZnCO3), Zincite (ZnO) and Calamine
(ZnCO3)
• Two methods of manufacture – pyro metallurgical, hydro metallurgical
Pyro-metallurgical process:
Concentration – Zinc ore is first concentrated by subjecting it to froth floatation.
• The finely powdered ore is immersed in a mixture of oil and water
• Zinc ore particles come up in the froth formed by oil whereas the impurities settle
down in water
Roasting – Ore is subjected to heating in a hearth furnace in presence of air
• Purpose of roasting is expulsion of sulphur and conversion of sulphate into oxide
• 2ZnS + 3O2 = 2ZnO + 2SO2
This sulphur dioxide is used for manufacture of sulphuric acid.

37. Zinc

38. Zinc
Smelting – Roasted zinc ore and powdered coal are charged
into special vessels called retorts and placed in a furnace.
• It is heated at a temperature of 1450 ⁰C
• Zinc is vaporized and collected in condensers attached to
retorts
• ZnO + C = Zn + CO
• Zinc distillate is collected and solidified to give spelter zinc.

39. Zinc

40. Zinc
Refining – The spelter zinc may be refined to 100%
purity by electrolysis
• Hydrometallurgical process: The roasted ore is
leached with sulphuric acid.
• The solution is filtered and treated with lime.
• This treatment precipitated chief impurities like iron
and aluminium.
• The solution left behind contains mainly zinc sulphate.
• Zinc is recovered by Electrolysis method

41. Hydro-metallurgical process

42. Zinc
Properties:
• Whitish in colour, bright lustre
• Density – 7.4 gm/ cm3
• Specific gravity – 6.2
• Melting point 419 ⁰C, boiling point 907 ⁰C
• Tensile strength – 700 to 1400 kg/cm2
• In moist air, zinc surface gets covered by a dull
basic zinc carbonate
• Spelter zinc is easily attacked by acids

43. Zinc
Applications:
Galvanizing – coating iron and steel with a protective layer of
zinc, 40% of total world production of zinc is used in
galvanizing
Die Casting (due to low melting point and resistance to shock) –
zinc in alloy form is used for die casting
Zinc die-casting alloys use in automotive industries and
electrical industries such as for carburettors, speedometer
frames, parts of hydraulic brakes, wipers, grills for
radiators, in washing machines, vacuum cleaners, motor
housing
Brass Making – copper alloys with zinc forms group of alloys –
Brasses 20% of zinc production is consumed in manufacture
of brasses

44. Galvanizing

45. Die Casting

46. Brass Making

47. Corrosion of Metals
• Introduction: Corrosion is the deterioration of
a metal as a result of chemical reactions
between it and the surrounding environment.
• Both the type of metal and the environmental
conditions, particularly what gases that are in
contact with the metal, determine the form and
rate of deterioration.
• The corrosion process is undesirable and
changes produced during corrosion may be
considerably harmful in the service life of
metal.

48. Corrosion of Metals

49. Corrosion of Metals
• Corrosion is a matter of chemical affinity of a metal with a
particular environment.
• Many metals may remain unaffected in water for many years
and some other metals may destroy from surface inwards in a
much shorter time.
• Metals wasted through this process is 2% of the metal quantity used
in a year.
• Corrosive Environments:
(a) Atmosphere
(b) Water
(c ) Soil
(d) Industrial gases
(e) Chemicals

50. Corrosion of Metals

51. Corrosion of Metals
Atmospheric Corrosion – Metals get quickly oxidized because of their
strong affinity for oxygen and atmospheric moisture acts as a
destructive agent.
• In industrial area, atmosphere is polluted with industrial gases
which react easily with exposed surfaces of metals producing
undesired compounds.
• Atmospheric corrosion form thin film of oxide which may be thin
and uniform, thick and non-uniform or porous or non-porous
• If this film is of non-porous nature, it will protect metal below
from further corrosion
• If this film is of porous nature, oxygen may further penetrate
deeper and corrosion may continue
• Example: Chromium – thin and non-porous layer
• Aluminium – strong and non-porous layer (layer of
aluminium oxide Al2O3)

52. Corrosion of Metals

53. Corrosion of Metals
Rusting of Iron: Special significance in engineering practice
• Corrosion cells are formed in those areas where there is some
difference in composition of iron or steel
• The humid air causes the rusting of steel (the formation of oxides on the
surface of steel), also the atmospheric conditions along with rain produces
oxidation and corrosion.
• The physical and mechanical properties are affected and cracks and
discontinuities may form in the oxide film, due to electro-chemical action
on the metal surface
• Once rusting is initiated, it gradually increases and corrodes iron.
• Rusts are peeled off from the swelled surface of iron. It is serious problem
as the surface becomes rough with rusted iron projections. This may injure
users. Also, the loss of steel sectional area may cause failure of structural
elements.
4Fe + 6H2O + 3O2 = 4Fe(OH)3
• When water is removed from ferric hydroxide, there is a change in
composition from ferric hydroxide to the red oxide or rust:
4Fe(OH)3 = Fe2O3 + 3H2O

54. Corrosion of Metals

55. Corrosion of Metals
Underwater Corrosion – the attack of water on the surface of the
metal for considerable time
• This takes place when metal products remain in contact with
water
• Example: Pipes, tanks, submerged parts of ships in which
dissolved oxygen is the important factor for corrosion
Corrosion Under Soil – In metallic structures which is embedded
within soil for long time show corrosion.
• This is due to acidity of soil, electrical conductivity of the soil
and moisture content in the soil
Chemical Corrosion – Metal undergoes destruction due to chemical
reaction between metal and liquids or gases with which it has come
in contact. Chemical environment may be by acids, bases, salts,
gases and solvents and behaviour of metal depends on its affinity
for these chemical environments.

56. Underwater Corrosion

57. Prevention of Corrosion
Selection of Metals – All metals are not stable in all environments.
For selection of metal there is no set rules but it becomes useful
by
(i) Analysing the exact nature of the environment in which the metal is
to be used
(ii) Obtaining information about behaviours of different metals in
particular environment
(iii) Selecting the one which will give the best performance
Example: Use of metal as a sheeting material in boiler feed water valves – choices
are iron, plain steel and special stainless steel
• Iron and plain steel may be cheap at initial stage but will rust fast in this
situation. Stainless steel may be costly but best suited for a trouble free surface
• Aluminium and its alloys are quickly destroyed by fresh water or salt water
corrosion, so they should not be used for under water situations

58. Prevention of Corrosion
Reducing Corrosiveness of the Environment – Poor drainage of
rainwater may be responsible for accelerated corrosion of pipes
• Corrosion reducing chemicals called inhibitors may be added to boiler-
feed water, which increase the life of boilers
• Suitable treatment may be given to municipal water supply which is
often corrosive to pipes carrying the water
Application of Protective Coating – Coating serves both the purpose -
decoration and protection against corrosion
• Coating material may provide an inactive or an active covering over
the metal
Inactive coating: enamel painting, plastic coating, bituminous paints, oils
and greases
Function: To provide an insulation to the underlying material and does not
undergo a chemical change after its application on metal

59. Prevention of Corrosion

60. Prevention of Corrosion
Active coating: zinc coating on iron or steel (called galvanizing)
Function: To provide the underlying metallic surface by entering
into chemical reaction with the atmosphere
• Metallic zinc forms a thin layer of zinc carbonate, an insoluble film
and sticks at the surface and make it safe from corrosion
Methods of Giving Protective Coating
Dipping: Heating the coating metal to its melting point in a dipping
tank The metal is to be protected is then dipped into this tank and
a thin layer of the molten material gets deposited over it
• Example – Galvanizing in which zinc coating is given over iron
and steel, Tinning in which a coat of tin is given over brass and
other metals

61. Prevention of Corrosion

62. Prevention of Corrosion
Electroplating: Common method used for coating delicate products
• Electrolytic cell – (i) the metal to be deposited is made into an anode
• (ii) the metal which is to be coated is made to act as cathode
• As the electricity is passed through this cell, anode starts dissolving
and material released from anode gets deposited in the form of a
uniform layer over the metal acts as a cathode
• Examples: silver plating, gold plating, nickel plating, chromium plating
Spraying: Protective coat is applied by spraying over the metal to be
coated
• The coating material is first heated to atomizing temperature to convert to
a vapours state and then sprayed from a spray gun on to a warmed surface
of metal
• Example: Coating of zinc, tin, aluminium and copper on other metal

63. Electroplating

64. Prevention of Corrosion
Cementation: Sophisticated method of protective coating over delicate metal
• Metal objects are placed in a drum in which coating is fed in dust or
powder form
• Both materials are heated together for several hours
• Example: Coating of zinc on iron or steel objects
Cladding: Covering the metal surface to be protected with a thin sheet of the
coating metal
• Cladding is achieved by passing both the metal and the protective
cover through rollers at high temperatures and both are bonded
together
Anodizing: Oxide layer over the surface of aluminium metal sheet
• This oxide layer acts as a protective coating and saves the aluminium from
atmospheric corrosion

65. Prevention of Corrosion

66. References
• Building Construction : Dr B.C. Punmia
• Civil Engineering Material : Prof. Singh
• Internet Web Sites

67. Non-Ferrous Metals

68. Thanks…