Process for production of dialkali metal phosphates by ion exchange

摘要

A process for the production of dialkali metal phosphates by ion exchange is disclosed. The process is carried out by first ammoniating a water-soluble phosphate source such as phosphoric acid or monocalcium phosphate. The resulting ammoniated phosphate solution is then contacted with a weak cation exchange resin in the alkali metal form to produce the dialkali metal phosphate as well as an ammonium-loaded weak cation exchange resin. The cation exchange resin is regenerated by contacting it with an alkali metal salt solution which effects an exchange of alkali metal from ammonium to produce a rgenerated weak cation exchange resin in the alkali metal form as well as a water-soluble ammonium salt corresponding to the initial alkali metal salt. The process may be carried out in conventional fixed or pulsed bed ion exchange systems although it is most advantageously carried out in an Advanced Separation Device which is a multi-chambered device which enables the process to be carried out both continuously and with a greater degree of efficiency than is possible using conventional ion exchange systems.