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SUBJECT: Engineering Materials

INSTRUCTOR: Engr. Nazeer Ahmed Anjum

Students Name: Saad Sharif Saleemi UW-13-ME-BSc-002

Haseeb Tariq UW-13-ME-BSc-014

DEPARTMENT OF MECHANICAL ENGINEERING

3 TOPICS OF PRESENTATION

Refining of Aluminum Properties Applications

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Aluminum

Refining

Introduction to refining of aluminum

Bayer process

Hall process

Properties

Applications

Question/answers

5 Aluminum

Aluminium is a silvery-white, soft, nonmagnetic, ductile metal

6 What is refining?

7 Refining of aluminum:

Introduction

Alumina is the common name given to aluminum oxide (Al2O3). Alumina is produced from bauxite, an ore that is mined from topsoil in various tropical and subtropical regions.

The Bayer process is the primary process by which alumina is extracted from bauxite.

To produce pure aluminum, alumina is smelted using the Hall–Héroult electrolytic process. This process is referred to as primary production.

8 Scheme for refining of aluminum

bauxite• Bayer

process

alumina• Product

of Bayer process

aluminum

• Hall heroult

9 Bayer process:

The Bayer process is carried out in four steps

1. Digestion

2. Clarification

3. Precipitation

4. Calcination.

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11 Hall–Héroult process

The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) in molten cryolite, and electrolysing the molten salt bath, typically in a purpose-built cell

12 Principle of Hall process

“when the alumina solution is electrolyzed in molten cryolite (), pure aluminium is produced.”

The reduction cell bottom serves as a cathode, and coal bars immersed in cryolite serve as anodes. Molten aluminium is deposited under a cryolite solution with 3-5% alumina. During this process, temperatures reach 950°C, considerably higher than the melting point of the metal itself, which is 660°C

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Properties of Aluminium

15 Physical Properties

•Symbol: Al•Melting point: 1,221°F (660.3°C)•Electron configuration: [Ne] 3s2 3p1•Atomic number: 13•Boiling point: 4,566°F (2,519°C)•Atomic mass: 26.981539 ± 0.0000008 u•Discoverer: Hans Christian Ørsted

16 Mechanical Properties

Young's modulus 70 GPa Shear modulus 26 GPa Bulk modulus 76 GPa Poisson ratio 0.35 Vickers hardness 160–350 MPa Brinell hardness 160–550 MPa

17 Some Other Properties

Corrosion resistance Thermal expansion 23.1 (at 25°C) Thermal conductivity 237 Electrical resistivity 28.2 nΩ·m (at 20

°C) Light weight Recyclable

18 Application of Aluminum

Building and structure

19 Transport

transportation hardware such as aircraft, trains, ships and motor

20 Air Craft

In aircraft construction, aluminum is used for frames, exteriors, wiring and electrical systems;

21 Automobile

automotive industry it is used for frames, bodies, blocks, pistons, valves, bumpers, wheels and other parts.

22 Pakages

aluminum has few rivals when it comes to the packaging of food, beverages and pharmaceuticals

23 Electrical equipment

Aluminum has almost entirely replaced copper. Aluminum is also increasingly replacing copper in transformers.

Casing, mountings and other parts or equipment used in communications and electronics.

General office equipment, fuse boxes, satellite dishes, household appliances, television sets and sound systems

24 Different products

furniture and household fittings

Transportation containers, gas cylinders, masts, bicycles and caravans

25 ANY QUESTION??

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