Novel Technique for Purification of Fertilizer Phosphoric Acid with Simultaneous Uranium Extraction

A process codenamed PHOSPURIN is described for the purification of Fert Phosphoric acid with simultaneous extraction of Uranium compounds from acid. This includes maintaining the acid stream at different redox potentials for the necessary extraction of all the metals & rare earths using Solvent Extraction technique. Details are also provided on the extraction behavior of various cations and rare earths from fert acid media employing redeveloped Phosphate reagent (codenamed KROPHOS-18) in kerosene system.The effects of various parameters, such as the concentration of acid, metal ion and extractant, nature of the diluents etc., on the extraction of various cations have been investigated. Based on the extraction data, most of the cations like Fe (II) & (III), Al, Mg, Ca, Mn, Na, K, heavy metals like Arsenic / Cadmium, rare earths including Uranium etc., are all being extracted with high to very high separation factors from all molar fertilizer phosphoric acids.The practical utility of the extractant & the process has been demonstrated by tests on commercial fert phosphoric acid. It has been conclusively found that KROPHOS-18 has good properties, such as high distribution coefficient, good stability, acceptable kinetics, good phase separation etc.