Abstract

The extraction of Eu(III) was investigated from nitrate medium by CYANEX921 (C921). It was found that the chemical formula of the main extracted species in the organic phase is Eu(NO₃)₃.3[C921] for extraction by C921. It was found that the Eu(III) percent extracted from toluene, n-hexane, cyclohexane and kerosene was nearly similar but with faster phase separation in favor of toluene. The relation between the shaking time and the percent of extracted C921 (%E) was studied at different pH. It was found that the best shaking time is 20 min at pH between 0.5-1.0, whereas at pH 2.0 the best shaking time is 15 min. The maximum extraction of Eu(III) was found to be after 5 min at pH 3.0. The extraction of Eu(III) increase with increasing of pH, however, the extraction precent increase from 28.5% at pH 0.5 to 98% at pH 3.0 The calculated average for the extraction constant is 6.58 at pH 3.0 under various C921 concentrations. From the data obtained, it was found that arsenazoIII (AIII) is a good stripper for Eu from organic phase which reach to 65% at pH 2. The stripping of Eu decreased from 57% to 2% when rising the pH from 0.5 to 11.

Key word: Solvent extraction, europium(III), CYANEX92, nitrate media, stripping.