Aluminum profiles – sustainable and environmentally friendly
After oxygen and silicon, aluminum is the third-commonest element on Earth. On account of its strong tendency to react with non-metals, especially oxygen, aluminum does not occur naturally in metallic form. The raw material for producing primary aluminum is bauxite, itself a product of weathered limestone and silicate minerals. The production of aluminum from bauxite is a two-stage process. First, aluminum oxide – a white powder also known as alumina – is extracted from the bauxite. The aluminum oxide is then reduced to pure aluminum by means of fused-salt electrolysis, a major cost factor in the production of primary aluminum. Having an economically and environmentally viable source of energy for the production of primary aluminum is vitally important today. In Europe, the energy required for producing aluminum thus comes predominately from hydroelectric power.
An important criterion in assessing the environmental sustainability of aluminum is the continued existence of the energy originally invested in producing the metal. Melting down aluminum requires just 5 percent of the amount of energy first used in smelting it. Aluminum is the ideal recycling metal. Recycled aluminum retains its material-specific characteristics and can be produced over and over again for the same application. Aluminum can circulate in an environmentally sustainable cycle virtually forever. Secondary aluminum is produced either by melting down capital scrap metal (i.e. old aluminum products) or with factory scrap metal leftover from the production process. Factory scrap normally goes right back into the smelting process used for making aluminum. Secondary aluminum is a reusable material that can be employed in the production of cast aluminum alloys or – together with primary aluminum – for manufacturing new products.
Aluminum recycling has been a standard practice for a hundred years. The high price of scrap makes recycling an attractive proposition. Metal dealers, processors and aluminum smelting plants all engage in recycling. In the construction industry, recycling organizations such as the A.U.F. have emerged to assure economic recycling of aluminum profiles from windows and façades, which are then used for producing new profiles.
The steps in recycling an aluminum window or façade are as follows:
- Removal of the unit
- Shredding and sorting
- Melting down the aluminium
Secondary aluminum obtained in this way can be used for manufacturing new profiles.
A recycling ratio of 93 percent can be achieved for aluminum profiles. The figure below shows the recycling loop for aluminum profiles.
When dismantling or demolishing a building, every effort should be made to maximize the profitable continued use or reuse of recovered materials and to minimize waste. Given the durability of products made of aluminum and the excellent possibilities for recycling them, it is entirely legitimate to view aluminum as an efficient, environmentally sustainable material.