Uranium extraction from wet process phosphoric acid. A liquid membrane approach

Liquid membrane (LM) technology offers a new approach for extracting mineral values from aqueous streams, such as uranium from Wet Process Phosphoric Acid (WPPA). This approach utilizes a water-in-oil emulsion as the vehicle to simultaneously remove uranium from a WPPA feed and concentrate it in the internal aqueous phase of the LM emulsion. The simultaneous extraction and stripping operation of the LM process resulted in a kinetically controlled uranium separation, removing some of the limitations of the thermodynamically dominated solvent extraction process. This difference in basic mechanism manifested itself in a unique response to variation of the physicochemical parameters affecting the transport and concentration of uranium. In contrast to solvent extraction, LM extraction exhibited an inverse temperature response, insensitivity to phosphoric acid strength of 5 to 8 M, and insensitivity to the concentration of complexing agent in the range of 0.07 to 0.14 M