Uranium(VI) extraction from concentrated Egyptian wet-process phosphoric acid using a synergistic organophosphorous solvent mixture

Ahmed F Abdel-Magied,Mostafa I Amin

doi:10.1007/s40090-015-0056-6

Ahmed F Abdel-Magied, Mostafa I Amin

Open Access

https://doi.org/10.1007/s40090-015-0056-6

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Abstract

Uranium(VI) recovery from concentrated Egyptian hemi-dihydrate wet-process phosphoric acid, 9.2 M, is investigated using synergistic organophosphorous solvent mixture of dinonyl phenyl phosphoric acid (DNPPA) and tris(2-ethylhexyl)phosphate (TEP). The effect of various factors such as [DNPPA] concentration, [TEP] concentration, phosphoric acid concentration, shaking time, aqueous: organic phase’s ratio (V aq/V org), stability of the solvent, the diluents effect, and temperature on the degree of extraction has been established. The effect of different stripping agents was investigated. The enthalpy change of the uranium extraction process was determined and the extracted uranium is further subjected to a second cycle of extraction [0.3 M D2EHPA + 0.075 M TOPO], scrubbing impurities (5 M sulfuric acid), and finally stripping with 1 M (NH4)2CO3 solution. Precipitation of uranium in highly pure UO3 product using hydrogen peroxide and heat treatment at 375 °C were carried out.

Highlights

Uranium plays an important role in the generation of nuclear power but has limited resources
We have shown that synergistic mixtures of D2EHPA-TOPO [16], PC88A-DBBP [17], and D2EHPA-DBBP [18] are suitable for successful extraction of hexavalent uranium from wet phosphoric acid (WPA)
The addition of tris (2-ethylhexyl) phosphate (TEP) to the organic phase lead to an enhancement in the uranium(VI) extraction distribution coefficient

Summary

Introduction

Uranium plays an important role in the generation of nuclear power but has limited resources. Solvent extraction has been found to be a successful process for industrial recovery of uranium from phosphate [2, 5,6,7,8,9,10,11], other different methods such as ion-exchange [12], membrane separation [13], and precipitation [14] have been extensively investigated. The two extractants are interacting with one another to some extent in the organic phase, and the formation of mixedextractant metal product species must be strong enough for net synergism to be observed. We have shown that synergistic mixtures of D2EHPA-TOPO [16], PC88A-DBBP [17], and D2EHPA-DBBP [18] are suitable for successful extraction of hexavalent uranium from wet phosphoric acid (WPA). The synergistic combination of DNPPA with TEB for the extraction of uranium from concentrated WPA is described

Experimental procedures

Results and discussion

M 6 M HCl 8 M

Conclusion