Desalination, 235 (2009), 9-32.

This work was carried out under the specific collaboration agreement between the Bhabha Atomic Research Centre (BARC) from India and the Commissariat à l’Energie Atomique (CEA) from France. This paper summarises first results of review and research on the possible extraction of uranium from the concentrated brine rejected by integrated nuclear desalination systems, which both partners are currently developing in the two organisations. Three innovative and efficient methods of uranium extraction have been proposed: 1) Resin grafted with calixarene: this method has the advantage of very high selectivity. Its performances, especially for large-scale extraction, still need further R&D and optimisation; 2) Magnetic separations: yet another method with high selectivity, easy separation and affording high degree of material recovery. The method, however, is in developmental stage; 3) Canal system with Braid adsorbents: high selectivity. Appears to be feasible in conjunction with existing technology. It would nonetheless require large amounts of adsorbents and adequate infrastructure.

Desalination, 182 (2005), 449-460

Seawater usually contains sixty elements from the Periodic Table. The brine, rejected by a desalination unit, is a concentrate of all compounds contained by seawater. However, some of the elements are very scarce on land and/or are very expensive. There is thus a strong motivation for extracting these materials. Current practice in countries using large-scale desalination is to reject brine back to the sea. Increasing ecological objections are now being voiced since this rejection leads to a degradation of local fauna and flora. Extraction of materials and subsequent brine conditioning for surface storage would therefore be also another advantage for these integrated desalination plants, making them more environmentally friendly. This paper summarizes our preliminary investigations to achieve the above objectives. Elements of interest were first selected on the basis of several economic, physical-chemical and technical criteria. Research was then undertaken to elaborate a common extraction method. After several different solutions, the protocol finally retained comprises a first extraction of Phosphorus through purification by alum. The next step is the recovery of Caesium through an innovative liquid–liquid extraction approach, based on the use of Calixarenes. Indium is then recovered by another liquid–liquid extraction with the help of organic acids. In the final phase germanium and magnesium are extracted. The remaining solution is principally composed of sodium and potassium chlorides, which are separated by hot lixiviation techniques, using the different solubilities of NaCl and KCl. The protocol of extraction thus elaborated would now require exhaustive economic evaluation and experimental verification. These are currently in progress.