PREPARATION OF POTASSIUM CARBONATE BY ELECTRODIALYSIS TECHNIQUE

A new process is developed on laboratory scale for the preparation of potassium carbonate employing electrodialysis technique by the metathesis reaction of sodium carbonate and potassium sulphate solutions. Interpolymer ion-exchange membranes based on polyethylene and styrene-DVB copolymer are packed in a 19-compartment unit having 12 cm multiplied by 12 cm effective cross-sectional area. A novel built-in flow system to handle eight flows is incorporated in the electrode housings. Operating parameters such as current density, concentration of reactants, concentration of products and anode material are studied. Under optimised conditions 1. 5 N solution is obtained with 98% purity of the product. The power consumption is congruent 1. 3 kWh/kg of potassium carbonate with a current efficiency greater than 95%. Sodium sulphate is obtained as a byproduct.