Strontium Isotope Effect in Liquid-Liquid Extraction of Strontium Chloride Using a Crown Ether

Abstract

Isotope effects in a liquid-liquid extraction of strontium with dicyclohexano-18-crown-6 (DC18C6) were investigated. Unit mass enrichment factors were observed to increase with concentrations of strontium salt in an aqueous phase. Isotope distinguishing ability of DC18C6 to strontium isotopes was calculated as an intrinsic separation factor to be K c =1.00051±0.00004. An odd mass number isotope, 87Sr, was recognized to behave differently from even mass number isotopes, 84Sr, 86Sr and 88Sr. The enrichment factor induced by a nuclear property (odd or even mass number) other than the mass difference was εO/E = −8.0 × 10−4 which was observed with 3.2M Sr aqueous solution. Isotope shift of energy state for 5S-orbital of strontium produces the isotope shift in vibrational energy between the strontium ion and the DC18C6.