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Aluminium production

    1. Geologists examine the rock and establish how much bauxite it contains.
    2. Bauxite deposits are usually right under the surface, facilitating excavation.
    3. The mine ore is transported to a reprocessing plant where impurities are eliminated and thus aluminium oxide or alumina is obtained.
    4. Alumina is then transported to electrolysis plants.
    5. Electrolysis is conducted in large steel tubs, which are all coated with graphite that also serves as a cathode. Large graphite blocks floating in the middle of the tub constitute anodes. Electrolysis is conducted on alumina melted in melted cryolite (an aluminium compound that significantly reduces the melting point). When electric current passes through the installation, oxygen contained in aluminium oxide is collected on the carbon anode, producing carbon dioxide; the emerging metal is heavier and collected at the bottom of the container. Two tonnes of aluminium oxide are obtained from four tonnes of bauxite and, consequently, one tonne of aluminium is obtained from two tonnes of aluminium oxide. After electrolysis is completed, aluminium is refined to an about 99.9% purity rate.
    6. The metal is then reprocessed into forms suitable for the needs of other industries. 

      Interesting Facts

        • 4 tonnes of bauxite ore → 2 tonnes of alumina → 1 tonne of aluminium
        • By applying 1 kg of aluminium in the construction of an average-size lorry, 28 kg less carbon dioxide is emitted into the environment.
        • By applying 1 kg of aluminium in the construction of a city bus, 40–45 kg less carbon dioxide is emitted into the environment.
        • Aluminium products are easy to repair.
        • Opel Vectra is made of 180 kg of aluminium.
        • Audi A8 is made of 231 kg of aluminium.