Uranyl compounds solvent extraction

The uranium ore concentrate or yellowcake is not a very pure substance. But, the dissolution, filtering, solvent extraction, and evaporation processes in the production of uranyl nitrate result in a reasonably pure uranium compound such as specified by the American Society for Testing and Materials standards. Thus, a chemically pure form of natural uranium is available as uranyl nitrate or UO3 prior to introduction of safeguards. Because of the high neutron-capture cross section for " N, uranyl nitrate is not a likely candidate as a fuel for a natural uranium reactor. However, pure UO3 could potentially be used as a ready source for fuel in a specially designed plutonium production reactor thus raising a potential diversion concern. 

Sclents differ greatly in their ability to extract compounds of metals from aqueous solution. For example, uranyl nitrate is strongly extracted by dieth ether, hexone, TBP, and many other oxygenated organic solvents, but it is not extracted at all by benzene, kerosene, or other... 

Because of the complications introduced by ferric iron, Audsley et al. concluded that a solvent that would be selective for thorium in the presence of ferric iron and that would not be inhibited by phosphate would be preferable to the Dapex solvent. They concurred with the conclusion of Crouse and co-workers at Oak Ridge National Laboratory [CS], that long-chain primary amines selectively extract thorium in the presence of uranyl, ferric, and phosphate ions. Compounds of this type are now the preferred extractant for thorium in such systems. Application of this so-called Amex process to thorium extraction from monazite is described in Sec. 8.6. 

TRLIF has a range of potential applications to other ScF investigations. The methods discussed in the chapter are not limited to uranyl chelates in ScF CO2 and are applicable to other ScFs and other compounds such as polyaromatic hydrocarbons, lanthanide complexes, and luminescent chemical probes. Future investigations with TRLIF in ScFs could involve work on analytical and industrial extraction processes, determination of physical parameters such as solubility, or fundamental studies of solvent-solute interactions in ScF systems. 

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