Production of potassium phosphates by ion exchange

Abstract

A process for producing potassium phosphates by ion exchange using an Advanced Separation Device (ASD) is disclosed. The process is carried out by supplying a phosphate salt solution, a washing solution and a potassium salt regeneration solution to respective fixed feed ports in periodic fluid communication with a plurality of resin-filled chambers moving about a circular path. Passage of the phosphate salt solution through potassium loaded resin forms potassium phosphates and cation loaded resin by ion exchange. After washing out residual salts, the cation loaded resin is regenerated by adding a potassium salt which loads the resin with potassium and strips it of the cation in the form of a soluble cation salt. By virtue of the ASD, potassium phosphate may be produced continuously and with greater efficiency than is possible with conventional ion exchange processes since the potassium salt and phosphate salt feed solutions may be fortified in an intra-stage fashion, i.e. during the course of the ion exchange or regeneration stages. In similar fashion, the pH may be adjusted in an intra-stage fashion.