Thu February 14, 2013 By:

what is preparation of Na2CO3 commercial and laboratorycal?

Expert Reply
Thu February 14, 2013
On industrial scale sodium carbonate is prepared by Ammonia Solvay Process.
CO2 reacts with ammonia to form ammonium carbonate.
2NH3 + CO2 + H2è(NH4)2CO3
Ammonium carbonate further reacts with CO2 to form ammonium bicarbonate.
(NH4)2CO3 + CO2 + H2è2NH4HCO3 (aq.)
Ammonium bicarbonate then react with NaCl to form sodium bicarbonate.
NH4HCO3 + NaCl èNaHCO3 + NH4Cl
Due to exothermic nature of above reactions, solubility of NaHCO3 increases. To counter this effect , lower part of Solvay tower is cooled , ppt of NaHCO3 are separated by vacuum filtration and washed to remove ammonium salts.
Dry sodium bicarbonate is heated in rotary furnace called "CALCINER" to give anhydrous sodium carbonate or soda ash. Carbon dioxide is recirculated to carbonation tower.
2NaHCO3 èNa2 CO3 + CO2 + H2 O

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