Reaction of Sodium hydroxide & Sulfur Dioxide leads to generation of Sodium Sulfite. Because of limited market potential need is felt to convert Sodium Sulfite to marketable Sodium Sulfate.

Oxidation of Sodium Sulfite yields Sodium Sulfate. According to conventional process Sodium Sulfite is treated with oxidizing agents. Even though the process is simple, it is not cost effective & environment friendly. High value oxidizing agent gets consumed during the process. Since the value of Sodium Sulfate is low, any additional cost incurred will drastically increase the raw material cost & in turn reduce the profit margin. Also the by-products generated should be treated which again leads to increase in treatment cost.

Alternatively Sodium Sulfite can be oxidized by air in presence of catalyst. The atmospheric oxygen gets absorbed in aqueous phase. This oxygen reacts with Sodium Sulfite in presence of catalyst to give Sodium Sulfate. The catalyst can be recovered completely by extraction. The catalyst thus recovered can be reused without loss of its catalytic activity.

Recovered Sodium Sulfate stream then taken for Antisolvent Crystallization for getting saleable quality of Sodium Sulfate. Antisolvent is the entity, which reduces the solubility of the solute. Antisolvents are generally organic substances, which reduces solubility of solute by binding the water. Proper application of Antisolvent can reduce the solubility of the solute to such an extent that solute will crystallize out from the solution. Thus energy intensive evaporation technology can be replaced by Antisolvent technology.

Applications:

Generation of Stream with mixture of Sodium Sulfite and Sodium Sulfate from Sodium Fusion reactions.

Benefits: