Production of Aluminium – Making a Material for Eternity
Strange parallel Discovery on the Road to Mass ProductionIn 1846, Henri Sainte-Claire Deville optimised the process described by Wöhler and published the process in book form in 1859. Apparently the remarkable parallel discovery of the fused-salt electrolysis process occurred as a result of this book. Charles Martin Hall developed the process in the United States while Paul Héroult did so in France. Both laid claim to the discovery as they foresaw its future economic value. Hall patented his idea in the USA and Héroult was granted patent rights for the rest of the world.
The electrolysis process laid the foundation stone for the large-scale economic production of aluminium. The price of aluminium fell by 90 per cent within ten years and aluminium was predestined for use in many fields of application.
Resource-Conserving ExtractionNowadays, a large part of the bauxite is processed to aluminium oxide in its country of origin today. The powdery oxide is then broken down into aluminium and oxygen in alumina-reduction cells using an electric current. Although 21 kWh of energy used to be needed to extract a kilogram of aluminium, the figure is now only 13-14 kWh. Today hydroelectric power is used to produce about 60 per cent of the electricity used in aluminium production.
Optimal Energy Balance over the whole Life CycleThe fact that only 5 per cent of the energy used for primary production is needed to recycle is important. It improves the impact assessment of aluminium considerably.
Furthermore, there is no loss in quality as a result of recycling. At the same time, aluminium’s properties help make many applications and articles much more economical and allow them to use resources more sparingly.