Bauxite to Aluminium

Aluminium

Introduction

Bauxite is the source material of aluminium. Global demand growth for aluminium in 2007 was 10.4%. The key global aluminium growth driver is China’s significant appetite for light metals such as aluminium, particularly for use in construction and engineering followed by transport.

Major uses of aluminium

Transport is more important to the aluminium industry than the simple tonnage figures indicate because (particularly in the aerospace segment) it is a market for highly specified products that command premium prices.

As the world’s leading automobile producing countries, the USA and Japan both show transportation as their most important end-use of aluminium.

Automobile manufacture dominates this sector, although the aviation, railway and marine sub-sectors are all important consumers of the metal.

Regional Differences in Estimated Aluminium Consumption by End Use, 2007

Automotive

The use of aluminium in automotive construction continues to increase.

After the oil crises of the 1970s, growth was largely driven by the incentive to reduce the weight of vehicles in order to improve their fuel efficiency. With petroleum and gasoline prices now at high levels, many manufacturers have dramatically reduced production of SUVs in favour of smaller more fuel-efficient cars that rely on greater use of aluminium.

Light motor vehicles (including passenger cars, SUVs, vans, etc.) constructed in North America in 2007 contain on average almost 150kg of aluminium, up 27% since 2000.

In 2000, aluminium overtook plastic to become the third most-used material in automobiles (with an average content of 100kg per vehicle), predominantly due to improved fuel economy, reduced emissions and enhanced vehicle performance. The amount of aluminium used in new European cars was 50kg in 1990 and is predicted to grow to 130kg by 2010. Elsewhere, it is expected that 145kg of aluminium will go into the average light automobile by 2010, with Chinese vehicles projected to contain as much as 170kg by that time.

The drivers of the increasing aluminium content in automobiles are:

the potential to reduce global greenhouse gas (GHG) emissions over the lifetime of the vehicle through fuel savings, even allowing for the CO₂ generated in the primary aluminium production process.

Fuel savings of 6–8% for every 10% reduction in weight.

Lighter vehicles have lower inertia, reducing stopping distances, and improving overall performance. Moreover, vehicles with aluminium frames are better crash energy absorbers than those with steel frames.

Aerospace

Over the last decades of the 20th century, aerospace was second only to the automotive industry as aluminium’s main area of growth.

Consumption of metal for the aerospace industry accounts for 10% of aluminium consumed by the transport sector (that is, 2.7% of total aluminium consumption).

The long-term growth rate of aerospace consumption is still forecast to be relatively strong, averaging approximately 5% per annum with industry sources estimating approximately 2,800 planes per year will be required until 2025.

Nevertheless, this growth is still under threat from substitution by non-metallic composites, typically made from glass or carbon fibre bound with epoxy resin.

Aluminium comprises 80–90% of the structural weight of present-generation aircraft such as the Boeing 747-400 jumbo, whose total structural and non-structural 100t mass contains 75t of aluminium.

The new generation double-decker Airbus A380 that made its first flight in April 2005 is 40% larger in terms of maximum take-off weight. Its main structure contains 140 tonnes of aluminium alloys.

But Boeing plans to reduce its aluminium usage by about half in its proposed super-fuel-efficient 250-seat 787 Dreamliner design (to make its first flight in late 2008). The fuselage is to be manufactured from a graphite-epoxy resin composite.

Railway and Marine Sub-sectors

Aluminium’s excellent resistance to corrosion and its ability to stand up to mechanical stress substantially lowers maintenance costs when used in the marine sector.

The use of aluminium in shipping grew substantially in the early 1990’s following a 15% per year growth trend in the European passenger and cargo sea transport sector. This was encouraged predominantly because the use of aluminium effectively limits the running costs of vessels, and enables shipping companies to effect more journeys in less time with reduced fuel consumption.

Aluminium also has applications in offshore construction, with a large part of the superstructures of oil drilling platforms being made entirely of aluminium.

In the railway sub-sector, Aluminium was able to meet certain technical challenges, because its lightweight properties allowed lower running costs and improved acceleration (many high speed trains run at more than 300km/h).

In North America and Africa especially, aluminium railcars offer the ability to carry increased payloads of minerals (such as coal) for transport between mines, production plants and port facilities.