Aluminiu m is the world’s most abundant metal and is the third most common element, comprising 8% of the earth’s crust. The versatility of aluminiu m makes it the most widely used metal after steel.
compounds have been used for thousands of years, aluminiu m aluminiu m metal was first produced around 170 years ago.
In the 100 years since the first industrial quantities of
aluminiu m were produced, worldwide demand for aluminiu m has grown to around 29 million tons per year. About 22 million tons is new aluminiu m and 7 million tons is recycled aluminiu m scrap.
The use of recycled
aluminiu m is economically and environmentally compelling. It takes 14,000 kWh to produce 1 tonne of new aluminiu m. Conversely it takes only 5% of this to remelt and recycle one tonne of aluminiu m. There is no difference in quality between virgin and recycled aluminiu m alloys.
aluminiu m is soft, ductile, corrosion resistant and has a high electrical conductivity. It is widely used for foil and conductor cables, but alloying with other elements is necessary to provide the higher strengths needed for other applications. Aluminiu m is one of the lightest engineering metals, having a strength to weight ratio superior to steel.
By utilising various combinations of its advantageous properties such as strength, lightness, corrosion resistance, recyclability and formability,
aluminiu m is being employed in an ever-increasing number of applications. This array of products ranges from structural materials through to thin packaging foils. Properties
The major advantages of using
are tied directly to its remarkable properties. Some of these properties are outlined in the following sections. aluminiu m Strength to Weight Ratio
Aluminiu m has a density around one third that of steel and is used advantageously in applications where high strength and low weight are required. This includes vehicles where low mass results in greater load capacity and reduced fuel consumption. Corrosion Resistance
When the surface of
aluminiu m metal is exposed to air, a protective oxide coating forms almost instantaneously. This oxide layer is corrosion resistant and can be further enhanced with surface treatments such as anodising. Electrical and Thermal Conductivity
Aluminiu m is an excellent conductor of both heat and electricity. The great advantage of aluminiu m is that by weight, the conductivity of aluminiu m is around twice that of copper. This means that aluminiu m is now the most commonly used material in large power transmission lines.
The best alternatives to copper are
aluminiu m alloys in the 1000 or 6000 series. These can be used for all electrical conduction applications including domestic wiring.
Weight considerations mean that a large proportion of overhead, high voltage power lines now use
aluminiu m rather than copper. They do however, have a low strength and need to be reinforced with a galvanised or aluminiu m coated high tensile steel wire in each strand. Light and Heat Reflectivity
Aluminiu m is a good reflector of both visible light and heat making it an ideal material for light fittings, thermal rescue blankets and architectural insulation. Toxicity
Aluminiu m is not only non-toxic but also does not release any odours or taint products with which it is in contact. This makes aluminiu m suitable for use in packaging for sensitive products such as food or pharmaceuticals where aluminiu m foil is used. Recyclability
The recyclability of
aluminiu m is unparalleled. When recycled there is no degradation in properties when recycled aluminiu m is compared to virgin aluminiu m. Furthermore, recycling of aluminiu m only requires around 5 percent of the input energy required to produce virgin aluminiu m metal. Aluminium Production
Aluminiu m is extracted from the principal ore, bauxite. Significant bauxite deposits are found throughout Australia, the Caribbean, Africa, China and South America. Open cut techniques are commonly used to mine the bauxite.
The bauxite is purified using the Bayer process. This process involves dissolving
aluminiu m trihydrate to leave alumina plus iron and titanium oxides. The iron and titanium oxides are by-products of the process and are often referred to as ‘red mud’. Red mud must be disposed of with strong consideration given to environmental concerns.
Approximately two tonnes of bauxite are required to yield one tonne of alumina.
The extraction of
from alumina is achieved using an electrolytic process. A cell or pot is used that consists of a carbon lined steel shell. This shell forms a cathode. A consumable carbon anode is suspended in liquid cryolite (sodium aluminium fluoride) held within the pot at 950°C. Alumina is dissolved in the cryolite by passing low voltages at high amperages through the pot. This results in pure aluminiu m aluminiu m being deposited at the cathode. Environmental Considerations
aluminiu m industry is very conscious of the environmental impact of its activities. The mining and smelting of aluminiu m, plus the disposal of red mud can have a major environmental impact if not done properly.
The industry is proud of its efforts and achievements in rehabilitating open cut mine sites and the restoring flora and fauna to these sites. Such efforts have been rewarded with awards from the United Nations Environment Programme and red mud disposal areas are now being successfully revegetated.
Environmental requirements are met on pot line emissions through the use of specialist scrubbing system.
The combination of two remarkable properties of
aluminiu m makes the need to recycle the metal obvious. These first of these factors is that there is no difference between virgin and recycled aluminiu m. The second factor is that recycled aluminiu m only uses 5% of the energy required to produce virgin material.
Currently around 60% of
aluminiu m metal is recycled at the end of its lifecycle but this percentage can still be vastly improved. Applications
The properties of the various
aluminiu m alloys has resulted in aluminiu m being used in industries as diverse as transport, food preparation, energy generation, packaging, architecture, and electrical transmission applications.
Depending upon the application,
aluminiu m can be used to replace other materials like cooper, steel, zinc, tin plate, stainless steel, titanium, wood, paper, concrete and composites.
Some examples of the areas where
aluminiu m is used are given in the following sections Packaging
Corrosion resistance and protection against UV light combined with moisture and odour containment plus the fact that
aluminiu m is non-toxic and will not leach or taint the products has resulted in the widespread use of aluminiu m foils and sheet in food packaging and protection.
The most common use of
aluminiu m for packaging has been in aluminium beverage cans. Aluminiu m cans now account for around 15% of the global consumption of aluminiu m. Transport
After the very earliest days of manned flight, the excellent strength to weight ratio of
aluminiu m have made it the prime material for the construction of aircraft.
These same properties of
aluminiu m mean various alloys are now also used in passenger and freight rail cars, commercial vehicles, military vehicles, ships & boats, buses & coaches, bicycles and increasingly in motor cars.
The sustainable nature of
aluminiu m with regards to corrosion resistance and recyclability has helped drive the recent increases in demand for aluminium vehicle components. Marine Applications
Aluminiu m plate and extrusions are used extensively for the superstructures of ships. The use of these materials allows designers to increase the above waterline size of the vessel without creating stability problems. The weight advantage of aluminiu m has allowed marine architects to gain better performance from the available power by using aluminiu m in the hulls of hovercraft, fast multi-hulled catamarans and surface planing vessels.
Lower weight and longer lifecycles have seen
aluminiu m become the established material for helidecks and helideck support structures on offshore oil and gas rigs. The same reasons have resulted in the widespread use of aluminiu m in oil rig stair towers and telescopic personnel bridges. Building and Architecture
use in buildings covers a wide range of applications. The applications include roofing, foil insulation, windows, cladding, doors, shop fronts, balustrading, architectural hardware and guttering. Aluminiu m
Aluminiu m is also commonly used as the in the form of treadplate and industrial flooring. Foils
Aluminiu m is produced in commercial foils as thin as 0.0065 mm (or 6.5 µm). Material thicker than 0.2mm is called sheet or strip.
Aluminiu m foil is impervious to light, gases, oils and fats, volatile compounds and water vapour. These properties combined with high formability, heat and cold resistance, non toxicity, strength and reflectivity to heat and light mean aluminium foil is used in many applications. These applications include:
Food protection and packaging
The above applications account for approximately 85% of the
aluminiu m consumed annually. The remaining 15% is used in applications including:
High pressure gas cylinders
Road barriers and signs
Lithographic printing plates
Typical Forms Available
is typically supplied by Aalco in the following forms: Aluminiu m
Square box section
Rectangular box section
Rice grain treadplate
This Data is indicative only and must not be seen as a substitute for the full specification from which it is drawn. In particular, the mechanical property requirements vary widely with temper, product and product dimensions. The information is based on our present knowledge and is given in good faith. However, no liability will be accepted by the Company is respect of any action taken by any third party in reliance thereon.
As the products detailed may be used for a wide variety of purposes and as the Company has no control over their use; the Company specifically excludes all conditions or warranties expressed or implied by statute or otherwise as to dimensions, properties and/or fitness for any particular purpose.
Any advice given by the Company to any third party is given for that party’s assistance only and without liability on the part of the Company. Any contract between the Company and a customer will be subject to the company’s Conditions of Sale. The extent of the Company’s liabilities to any customer is clearly set out in those Conditions; a copy of which is available on request.
This information has been sourced, reviewed and adapted from materials provided by Aalco - Ferrous and Non-Ferrous Metals Stockist.
For more information on this source, please visit
Aalco - Ferrous and Non-Ferrous Metals Stockist.