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extraction of metals. Metals can be extracted from their ores by electrolysis. Electrolysis is an expensive method and is used to extract very reactive metals such as aluminium, calcium and sodium. extraction of aluminium. aluminium is extracted from its ore, bauxite (A l 2 O 3 ). +.
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extraction of metals Metals can be extracted from their ores by electrolysis. Electrolysis is an expensive method and is used to extract very reactive metals such as aluminium, calcium and sodium. extraction of aluminium • aluminium is extracted from its ore, bauxite (Al2O3). + giant crucible for holding molten aluminium molten Al2O3 and cryolite to electric power supply - carbon electrodes steel tank lined with carbon molten aluminium produced from the decomposition of Al2O3 industrial electrolysis of aluminium
extraction of metals extraction of aluminium • the electrolyte is molten aluminium oxide and molten cryolite • electrolyte contains Al3+ and O2- ions • at the anode, O2- ions are discharged as O2 gas; O2 burns away the carbon anodes; C electrodes must be replaced 2O2-(l) O2(g) + 4e- • at the cathode, Al3+ ions are discharged as molten aluminium; collected in a crucible Al3+(l)+ 3e- Al(l) • overall reaction 2Al2O3(l) 4Al(l) + 3O2(g)