Extraction of Copper and Aluminium

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The Extraction Process of Copper and Aluminum Aluminum is difficult to extract from its ores, compared to other metals such as copper or iron. Because of its high reactivity it forms strong bonds with oxygen. Smelting with carbon cannot remove the oxygen as aluminum is a stronger reducing agent than carbon. Electrolysis has to be used currently as an economical industrial extraction process. Copper being much less reactive can be easily extracted by heating with various substances to remove its impurities. Copper compounds are heated to react with oxygen and pure copper is left, and can be refined with electrolysis. Copper ores used for commercial production of copper metal are typically chalcopyrite (CuFeS2) and chalcocite (Cu2S), which are sulfides of copper. Due to the low concentration of copper, raw minerals are crushed to small sizes and concentrated by froth flotation. The resulting material is heated with silica (SiO2) in flash smelting to remove the iron as slag. 2 CuFeS2 + 3 O2 → 2 CuS + 2 FeO + 2 SO2 FeO + SiO2 → FeSiO3 (slag) The copper matte (CuS) produced contains high concentration of copper, the sulfur is removed by blowing air through the molten matte. CuS + O2 → Cu + SO2 2 CuS + 3 O2 → 2 CuO + 2 SO2 This product is 98% pure copper but due to the broken surface created by the escaping sulfur dioxide gas, it is known as blister copper. To remove the oxygen, natural gas is blown through the molten copper oxide, and oxygen is burned off. The copper is then fed to electrolysis for refining. In an aqueous solution copper is dissolved at the anode, the ion moves across the electrolyte to the cathode and plates out. Cu → Cu2+ + 2 e- (anode) Cu2+ + 2 e → Cu (cathode) Aluminum are commercially extracted mainly from bauxite, which is mostly gibbsite (Al(OH)3). The Bayer process is used to refine the bauxite into alumina or aluminum oxide, which

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