Extraction of Cesium and Strontium Into Hydrocarbon Solvents Using Tetra-C-Alkyl Cobalt Dicarbollide

Tetra-C-alkyl derivatives of cobalt dicarbollide, CO(C2R2B9H9)2- (CoB2-R4 -R; = CH3, C6H13) are examined as potential cesium and strontium extractants for acidic and alkaline solutions. The mechanism of cobalt dicarbollide extraction is characterized, and extended into new non-toxic solvent systems. Extractions using 0.01 M H+CoB2-hexyl4 - in mesitylene and iethylbenzene are compared to 0.01 M H+CoB2 - in nitrobenzene. H+CoB2-hexyl4 - in diethylbenzene shows improved selectivity (104) forCs over Na in acidic solution. In dilute alkaline solution (0.01 M NaOH), H+CoB2 -hexyl4 - extracts Cs less efficiently, but more effectively removes Sr at higher base concentrations (1.0 M NaOH). Other aspects of the H+CoB2-hexyl4 -/hydrocarbon performace are comparable to the previously known H+CoB2 -/nitrobenzene extractant.