Aluminium oxide or alumina is a naturally occurring compound of aluminium and oxygen made from bauxite, a dull and earthy rock with high aluminium content. Bauxite is the most common ore of aluminium and you can find it in tropical areas Most of the bauxite mined end up producing aluminium with specific aluminium oxide equipment. Statistics have shown that Australia and Guinea have the largest bauxite deposits in the world. Countries like China, Brazil, and India also have a large amount of the rock.
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Aluminium oxide equipment, tailored around the unique properties of alumina
The key process in making aluminium oxide from bauxite is the Bayer process, that dates back to 1888 and crushes and mixes bauxite. The digestion of bauxite involves the use of concentrated sodium hydroxide or caustic soda to make aluminium hydroxide precipitate. To remove water and produce alumina, heat in a kiln at 1000-1200 °C (1832-2192 °F). Aluminium oxide making equipment such as a pneumatic conveying system ensures the passage of the mixture during production. It also makes sure of little or no loss of the mixture powder when passing through the blow-off tanks. It is important to carry out the Bayer process at appropriate conditions to ensure high production yield. Temperature and NaOH concentration, for example, affects the process digestion efficiency.
Different applications of aluminium oxide
The downstream process of aluminium oxide may involve further electrolytic reduction into pure aluminium. You may opt to smelt the alumina depending on your project. Despite being the most abundant metal on earth, aluminium does not occur naturally. The key process to making aluminium involves high electric power. This is why it is important to take measures such as using renewable energy sources like hydroelectric power plants to reduce air pollution.
Alumina is versatile and suitable for the chemical and medical industries, protective equipment and other applications. Engineers or manufacturers use aluminium oxide equipment to make alumina for ceramics, refractories, polishes, abrasives, and high temperature appliances like crucibles.
Environmental impact: from bauxite to alumina
The aluminium oxide making, from the extraction process of bauxite to smelting aluminium oxide into pure aluminium, consumes high energy. There is also a high emission of chemicals into the environment during production. Toxic chemicals like carbon and fluorine are released into the atmosphere, land and water, causing acute to severe health issues depending on level of exposure.
Asides from the adverse effect on humans, environmental pollutants can cause damage to plants, animals and even buildings. Studies have shown that it’s possible to reduce/remove airborne pollutants by condensation and incineration, amongst other methods. To remove pollutants in gases like hydrocarbons, by condensation, convert them to liquid vapour by lowering their temperature and increasing their pressure.
Note that aluminium is considered a “green metal” because of its recyclability. The European Union regulations aim to reduce 55% of greenhouse gases emission by 2030. They intend to achieve this by efficient refining and constant recycling of aluminium. They also encourage aluminium consumption replacement with alternatives such as zirconia instead of aluminium oxide for abrasives.