Aluminium oxide
About Aluminium oxide
Aluminium oxide is a chemical compound consisting of aluminum and oxygen. It is obtained in both primary and secondary aluminum production.
In primary production, aluminum is made from bauxite, an ore consisting mainly of aluminum minerals. Bauxite is mined, crushed and treated with lye to extract aluminum oxide. This process requires significant energy and resource investment.
In secondary production, aluminum is obtained from recycled aluminum. Scrap aluminum is melted down and cleaned to obtain aluminum. This process saves energy and resources compared to primary production.
The smelting process produces so-called drosses, which consist mainly of smelting salt, aluminum and aluminum oxide, and ammonia. In addition to the other components, aluminum oxide is recovered.
Cement industry
An important application of alumina is the production of cement clinker. The composition of the cement clinker is modified by the selective addition of alumina to a cement raw meal low in aluminum, and the clinker is given improved properties. The alumina is ground with limestone, clay, iron oxide and other raw materials during the cement manufacturing process to form a raw meal and burned at temperatures of about 1450 °C to produce cement clinker. Cement clinker is ground together with calcium sulfate and other admixtures to form cement, which is used in the construction industry. Cement is the binder in concrete and mortar used to build foundations, building structures and roads.
Another important application of alumina is the production of mineral wool, an insulating material. Alumina, silica and calcium magnesium silicates are used in the production of mineral wool. The alumina serves as a melting point lowering agent to facilitate the melting of the raw materials. The melted materials are spun into fibers and made into mats or boards, which are used in the construction industry for thermal, sound and fire protection.
The use of alumina from secondary aluminum production in these applications has several advantages in terms of sustainability. Recycling aluminum saves energy and resources, as the process of primary aluminum production is very energy intensive and requires large quantities of raw materials such as bauxite. In addition, recycling aluminum helps to reduce waste and reduce the environmental impact of aluminum extraction, including the release of greenhouse gases.
The use of alumina made from recycled aluminum also supports the circular economy by converting waste into valuable resources. By recycling aluminum products such as beverage cans, scrap metal or components, the alumina can be reused in new products instead of being disposed of as waste.
Overall, the use of alumina from secondary production in the manufacture of cement and mineral wool offers a sustainable solution. Recycling and reuse reduce energy consumption and environmental impact, while at the same time utilizing the valuable properties of alumina to produce high-quality and durable building materials. This helps to conserve resources and promote sustainable development.