| dc.description.abstract | Sodium hydrogen carbonate is used extensively in the
baking and pharmaceutical industries, where it is required in
very high purity. Commercially, it is prepared through the
solvay process.
In this project methods of preparing high purity grade
sodium hydrogen carbonate from Magadi soda have been
investigated. The method studied involves the carbonation of
soda ash at varying temperatures, pressures and stirring times.
Determinations of sodium carbonate and sodium hydrogen
carbonate concentrations were carried out titrimetrically using
methyl orange-indigo carmine and thymol blue-cresol red mixed
indicators at pH 3.8 and pH 8.3 respectively. This method gave
an accuracy of 97% ± 1.9% for concentrations upto 10 ppm.
Factors affecting the separation of sodium hydrogen
carbonate from the sodium carbonate solution have also been
studied. The solubility lities of the two salts differ greatly at 40°C
and this has been shown to be the best temperature at which
pure crystals of sodium hydrogen carbonate are formed. It has
also been shown, through mutual solubility studies, that solubility
of sodium hydrogen carbonate in saturated sodium carbonate
solution is very low, 0.23g NaHC03 in 51g Na2C03/100g H20. | en_US |
