How can you separate alumina from silica in a bauxite ore associated with silica? Give equations, if any.

Explanation

Pure alumina can be separated from silica in bauxite by Baeyer's process .The bauxite ore associted with solica is heated with a comcentrated solution of NaOH at 473 -523 K and 35-36 bar oressure under these conditions .alumina dissovless as sodium meta -aluminate and silca as sodium sicate leving behind the impurties .
`Al_(2)O_(3) (s) +2NaOH (aq) +3H_(2)O(l) to`
` 2Na[Al(OH)_(4)](aq) `
sodium meta-alumina
`SiO_(2)(s) +2NaOH (aq) overset(473-523 K) to `
`underset(Sodium silicate")NI_(2)SiO_(3)(aq) +H_(2) O(l)`
teh resulting solution is filtered to remove the undissolved impurities sodium meta - aluminate can be precipited as hydroated ali=uminum oxide by passing `CO_(2)` vapours the sodium silcate fromed connot be precipited and can be filered off.
`2Na[Al(OH)_(4)](aq) +Co_(2)(g) to`
`Al_(a)O_(3) .xH_(2)O (s) +A2NaOHCO_(3) (aq) `
the hydroted alumina thus precipitated isfitered,
dried and heated to give hack pure `Al_(2) O_(3)`
`underset("hydroted alumina")(Al)_(2)O_(3) .xH_(2)O(s) overset(1473 K) to underset("Pure alumina")Al_(2)O_(3) (s) +xH_(2)O`