Modeling of Potassium Sulfate Production from Potassium Chloride by Electrodialytic Ion Substitution

An experimental study was carried out on the preparation of potassium sulfate from potassium chloride by electrodialytic ion substitution. Effects of sulfate species, current density, and molar ratio of ammonium sulfate to potassium chloride were investigated. Results showed that ammonium sulfate was regarded as the optimum sulfate source because of the lowest energy consumption and cheap raw materials. When current density was set as 20 or 30 mA/cm2, the generated products can conform to the Chinese Government standard (GB20406-2006). A higher molar ratio can promote the substitution reaction more completely but results in larger loss of K+ ions and more increment of NH4+ ions in products. Moreover, a mathematical model was established to predict the product concentration. Results showed that there is a good agreement between experimental and computational concentrations.