Extraction-atomic-absorption determination of Rb and Cs in calcium chloride brines

The possibilities of using the mixture of ammonium di-2-ethylhexyldithiophosphate (NH4R) (0.5 M) and tributylphosphate (TBP) (2 M) in heptane for extraction separation of CaCl2 basis in the course of atomic-absorption analysis of Rb and Cs in calcium chloride brines are investigated. Study of the effect of the extracting agent composition on Ca, Li, Rb, Cs extraction is shown that synergetic (Ca, Li) and antisynergetic (Rb, Cs) effects observed in the system are maximum for an extracting agent of the composition NH4R:TBP=1:4. Substitution of the CaCl2 basis for NH4Cl with subsequent sublimation of NH4Cl permits to concentrate alkali elements and eliminate the effect of alkaline-earth ones. The proposed techniques permits to determine (0.5-3)x10-3 g/l Rb and Cs in calcium chloride brines with the total content of salts up to 500 g/l with the relative standard deviation not exceeding 0.07