3.5 Aluminium

Similar to steel, aluminium is a metal that has a multitude of uses. The difference is that aluminium is much less dense than steel, so is useful in applications when weight is an issue. For this reason it is popular in the aviation and automobile industry. These and other common uses of aluminium are listed below:

Table 3.5.1 Worldwide usage of aluminium

Category	Example of application	Worldwide usage	Millions of tonnes per year (Mt)
Transport
Cars	Wheels, gears, engine parts	18%	8
Trucks	Chassis, cab structure	7%	3
Other	Planes	2%	1
Industrial Equipment
Electrical Equipment	Conduit, sheathing, bus bar	4%	2
Mechanical Equipment	Heat exchangers, enclosures	7%	3
Electric Cable	As a substitute for copper	9%	4
Construction
Buildings	Extruded frames in for windows and doors, roofing and cladding	24%	11
Metal Products
Consumer Packaging	Drinks cans, food pouches, foil	1%	9
Domestic Appliances	Fridges, washing machines	7%	3
Other	Paints, powders and pigments	9%	4

(Source Sustainable Materials With Both Eyes Open [see reference 2])
Figure 3.3.1 sourced with permission from Sustainable Materials With Both Eyes Open. This book is available free to view online
http://withbotheyesopen.com/index.html

Again the biggest use is in the construction industry, but unlike steel which is mixed with concrete for foundations and infrastructure, aluminium is used for cladding windows, doors and roofing.

Aluminium's lower density and versatility comes at a cost; the manufacturing process to produce it requires increased energy – an order of magnitude higher than steel.

For this reason it may seem unintuitive for packaging and other “use-once” applications to be made from aluminium which requires so much energy to be manufactured but enters the waste stream immediately in this form. However the cost benefits of aluminium's versatility and low density outweigh the energy costs of producing it and the environmental costs when it becomes a waste.