Zirconium extraction into octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide and tributyl phosphate

Classical slope analysis techniques were used to determine the octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and nitrate stoichiometries for the extraction of zirconium by CMPO diluted with diisopropylbenzene (DIPB). The equilibrium constant for the extraction of zirconium by CMPO was also determined using classical slope analysis techniques. The extraction of zirconium by TBP in n-dodecane was used as a control to verify the zirconium species as Zr⁺⁴, and to verify the experimental methodology. Equilibrium [CMPO]_org and [TBP]_org concentrations were determined by accounting for the extraction of HNO₃ into both TBP and CMPO solvents. Nitric acid dissociation and aqueous phase activity coefficients were also taken into consideration. Organic activity coefficients, Zr⁺⁴ activity coefficients, Zr⁺⁴ hydrolysis, and consumption of TBP or CMPO by water were neglected. Nitrate and CMPO dependencies for the extraction of zirconium have been determined from this work to be: [see original abstract for formula]. An equilibrium constant of 1.13 × 10⁵ ± 1.48 × 75⁴ at 25°C was also determined for this reaction.