Fluorinated carbonates as new diluents for extraction and separation of f-block elements

The fluorinated carbonate BK-1 solvent was studied as a diluent in extraction systems with different extracting agents – CMPO, THDGA, CyMe4-BTBP, and CyMe4-BTPhen, which are the most promising molecules for separation of minor actinides and lanthanides. Dependence of the extraction properties of the system on the concentrations of HNO3 or extracting compound, kinetics of trivalent metal extraction and extraction of the ions by neat diluent (without the addition of extracting agent) were investigated. Based on the obtained results, BK-1 is a promising candidate diluent for f-block metal separation

DIAMIDE DERIVATIVES OF DIPICOLINIC ACID AS ACTINIDE AND LANTHANIDE EXTRACTANTS IN A VARIATION OF THE UNEX PROCESS

The Universal Extraction (UNEX) process has been developed for simultaneous extraction of cesium, strontium, and actinides from acidic solutions. This process utilizes an extractant consisting of 0.08 M chlorinated cobalt dicarbollide (HCCD), 0.007-0.02 M polyethylene glycol (PEG-400), and 0.02 M diphenyl-N,N-di-n-butylcarbamoylmethylphosphine oxide (Ph2CMPO) in the diluent trifluoromethylphenyl sulfone (CF3C6H5SO2, designated FS-13) and provides simultaneous extraction of Cs, Sr, actinides, and lanthanides from HNO3 solutions. The UNEX process is of limited utility for processing acidic solutions containing large quantities of lanthanides and/or actinides, such as dissolved spent nuclear fuel solutions. These constraints are primarily attributed to the limited concentrations of CMPO (a maximum of ~0.02 M) in the organic phase and limited solubility of the CMPO-metal complexes. As a result, alternative actinide and lanthanide extractants are being investigated for use with HCCD as an improvement for waste processing and for applications where higher concentrations of the metals are present. Our preliminary results indicate that diamide derivatives of dipicolinic acid may function as efficient actinide and lanthanide extractants. The results to be presented indicate that, of the numerous diamides studied to date, the tetrabutyldiamide of dipicolinic acid, TBDPA, shows the most promise as an alternative actinide/lanthanide extractant in the UNEX process