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Preparation of pure alumina (Al2O3) from...

Preparation of pure alumina `(Al_2O_3)` from bauxide ore.

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Pure alumina from bauxite ore can be extracted by the process of leaching . During leaching the powdered bauxite ore is heated with a cone (45%) solution ofNaOH at 473-523 K, when alumina dissolves as sodium meta aluminate and silica as sodium silicate leaving behind `Fe_2O_3, TiO_2` and other fmpufities behind. The impurities are filtered off and the solution of sodium meta aluminate is neutralized by passing `CO_2` when hydrated alumina separates out the hydrated alumina thus obtained is filltered, dried and heated to give back pure alumina.
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