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How can you obtain pure alumina from bauxite ore? Write the chemical equations involved. |
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Answer» Solution :Powdered ore is digested with a concentrated solution of NaOH at 473-523 K and 35-36 bar pressure. Alumina is leached out assodium ALUMINATE. `Al_(2)O_(3)+2NaOH+3H_(2)O to 2NA[Al(OH)_(4)]` The aluminate solution is neutralised by passing `CO_(2)` gas. Hydrated alumina is precipitated. `2Na[Al(OH)_(4)]+CO_(2) to Al_(2)O_(3).xH_(2)O+2NaHCO_(3)` Hydrated alumina is HEATED to get PURE `Al_(2)O_(3)`. `Al_(2)O_(3).xH_(2)O overset(1470K)(to) Al_(2)O_(3)(s) + xH_(2)O`. |
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