Aluminium is found primarily in bauxite ore and is remarkable for its ability to resist corrosion and its light weight. The metal is used in many industries to manufacture a large variety of products and is very important to the world economy.
Structural components made from the metal and its alloys are used extensively in the aerospace industry and in other areas of transportation and building. Production began about 146 years ago, but its production has far surpassed that of all other non ferrous metals. Whether measured in terms of quantity or value, the global use of this metal exceeds that of any other metal except iron, and it is important in virtually all segments of the world economy.
Production of this metal is electricity intensive. Global average electricity use for primary production of the metal is 15,300 kWh per tonne (kWh/t). This average has declined about 0.4% per year over the last twenty-five years.
On a regional basis, the averages range from 14 300 kWh/t in Africa to 15, 600 kWh/t in North America. Africa is the most efficient region due to new production facilities. New smelters tend to be based on the latest technology and energy efficiency is a key consideration in smelter development.
More than half of the energy used in non-ferrous metals is for primary aluminium production. Electricity consumption is particularly significant, with aluminium smelters using 1.9 EJ of electricity in 2006, about 3.5% of global electricity consumption.
Aluminium production can be split into primary production and recycling. Primary production is about 20 times as energy intensive as recycling and represents the bulk of energy consumption. The main primary producers are located in China, Russia, North America, Australia and Latin America.
Most of the energy consumed in alumina refineries is in the form of steam. The calcining (drying) of the alumina requires large amounts of high temperature heat. Due to a high demand for steam, modern plants use combined heat and power systems. The global average energy intensity was 12.0 GJ per tonne of alumina in 2006, with a range amongst different world regions between 11.2 GJ and 14.5 GJ per tonne (International Aluminium Institute, 2008).
The potential for energy efficiency gains in aluminium production is limited. With existing technology, energy use in the key steps of aluminium production can be reduced by 6% to 8% compared with current best practice. This is equivalent to final energy savings of about 0.1 EJ to 0.6 EJ per year.