A technique for the removal of iron from wet process phosphoric acid during manufacture utilizing chelating reagents was demonstrated. The process will benefit the phosphoric acid producer by reducing and/or eliminating the phosphate-containing solids formed as the phosphoric acid is concentrated and by allowing the production of DAP without the addition of supplemental nitrogen. Techniques for the recovery and recycling of the chelating agents were developed. Utilization of the process will be an economic decision by the individual phosphoric acid producer.
Hassan El-Shall and El-Sayed A. Abdel-Aal, University of Florida. February 2001.