Study of parameters involved in the protection of caustic soda from soda ash using lime-soda process

Abstract

This work is a study of the parameters involved in the production of caustic soda by the lime-soda process. Experiments were performed to determine the effect of reaction temperature on the per cent conversion of sodium carbonate . using both analytical grade reagents and commercial grade reagents. A temperature range of 60 to 100 DC was used for the experiments. The maxImum conversIOn was found to be at 90 DC, corresponding to 93.4% conversion using AR grade reagents and 82.0% conversion using commercial grade reagents. Moreover, at this temperature filtration of the reaction products was found to be easier than that produced at lower temperatures. Therefore this temperature is considered to be the optimum temperature for carrying out the reaction. Literature survey revealed that initial concentration of sodium carbonate of 10% to 20% (by weight) is used in industries. In these experiments the initial concentration of sodium carbonate was 20%. This was found to be satisfactory. The per cent conversion is also dependent on the initial concentration being higher at lower concentration of sodium carbonate. The caustic soda produced contained unreacted sodium carbonate. No calcium residue could be detected. Separation ofthe carbonate from the caustic and the concentrating of the caustic were not performed experimentally.