Numerical Modeling for Coextraction of Tc(VII) with U(VI) by n-Octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine Oxide from Nitric Acid Solution

Abstract

The coextraction model of Tc(VII) and U(VI) from nitric acid solution was developed on a tributyl phosphate (TBP)/n-dodecane system involving n-octyl(pheny1)-N, N-diisobutylcarbamoyl-methylphosphine oxide (CMPO). Technetium was considered to be extracted by the formation of Tc-CMPO and U-Tc-CMPO complexes in the presence of uranium. The distribution coefficient of technetium in the presence of uranium was defined by taking these complexes into account, and expressed as a function of nitric acid concentration, free CMPO concentration, and distribution coefficient of uranium. The equation of the distribution coefficient derived was applied to the previous data obtained in the mixed system of CMPO-TBP-dodecane at the low nitric acid concentration. It was found that the distribution behavior of technetium in the presence of uranium could be successfully simulated by the present coextraction model.

KEYWORDS:

• coextraction
• technetium ions
• uranium ions
• nitric acid
• distribution coefficient
• n-octyl(pheny1)-N
• N-diisobutylcarbamoylmethylphosphine oxide
• TBP
• Tc-CMPO complex
• U-Tc-CMPO complex
• dodecane