Raw aluminium comes from bauxite ore which once produced can be further processed and fabricated into various products used in construction, such as for architectural façades, brise soleil and rainscreen cladding.
In a nutshell:
- Raw aluminium predominantly comes from bauxite ore which is mined in various parts of the world, such as Australia and China.
- The process of extracting aluminium involves five stages: mining, refining, alumina production, electrolysis and casting.
- Molten aluminium can be cast into billets which is a popular resource in the construction industry thanks to its recyclable nature and malleability.
Raw aluminium primarily comes from bauxite ore, which is mined from various locations around the world such as Australia, Brazil, and China. Bauxite is primarily composed of aluminium oxide minerals such as gibbsite, along with other minerals such as quartz.
The process of extracting aluminium from bauxite involves several stages:
1. Mining: Bauxite ore is extracted from the earth's crust through open-pit or underground mining methods. The ore is then transported to processing plants for further treatment.
2. Refining: The bauxite ore undergoes refining to extract alumina, also known as aluminium oxide. This is typically done through the Bayer process, where the bauxite ore is crushed and mixed with a solution of sodium hydroxide under high temperature and pressure. This process dissolves the alumina content of the bauxite, leaving behind impurities such as iron oxide and silica.
3. Alumina Production: The dissolved alumina is then precipitated out of the solution, washed, and calcined to produce pure alumina.
4. Electrolysis: The alumina is then smelted using the Hall-Héroult process, which involves passing an electric current through a molten mixture of alumina and cryolite (a mineral used as a solvent). This process reduces the alumina to aluminium metal, which collects at the bottom of the electrolytic cell.
5. Casting: The molten aluminium is then cast into other forms such as billets for further processing and use in various industries. The use of aluminium billets is very popular in the façade industry because of the metal’s malleability, corrosion resistance, recyclability and lightweight properties making it suitable for a range of projects.