Solvent extraction IFuelreprocessinglCentrifugal contactors! Ruthenium jZirconiumThe contactor was also tested for application to the Civex and Thorex processes. SummaryA miniature short-residence-time centrifugal solvent extraction contactor and an eight-stage laboratory minibank of centrifugal contactors were used for testing the possibility of utilizing kinetic effects for improving the Separation of uranium from ruthenium and zirconium in the Purex process. Results of these tests showed that a small improvement found in ruthenium and zirconium decontamination in single-stage solvent extraction tests was lost in the multistage extraction tests -in fact, the extent of Saturation of the solvent by uranium, rather than the stage residence time, controlled the extent of ruthenium and zirconium extraction. In applying the centrifugal contactor to the Purex process, the primary advantages would be less radiolytic damage to the solvent, high throughput, reduced solvent inventory, and rapid attainment of steady-state operating conditions. The multistage mini contactor was also tested to determine the suitability of short-residence-time contactors for use with the Civex and Thorex processes and was found to be compatible with the requirements of these processes.

The alkaline leach and electrolysis process for zinc production is compared to the conventional acid sulfate process in terms of both energy saving and technical merit. In addition, the potential for industrial application of the alkaline process is discussed on the basis of present market conditions, possible future zinc market scenarios, and the probability of increased secondary zinc recovery.

Zirconium/TBP/Solvent extraction /Fuel reprocessing /Degradation SummaryRetention of zirconium in 30% TBP/nDD as a function of the age of zirconium organic solutions was studied by comparing distribution coefficients obtained from forward extraction and back extraction. The results of extraction studies showed that, although in freshly prepared zirconium organic solution zirconium is present only in scrubbable form, with the passage of time it undergoes conversion to a non-scrubbable form; scrubbing after 15 days of aging leaves ~40% of the zirconium in the organic phase. Zirconium that precipitated from aged organic solutions was identified as zirconium monobutyl phosphate or zirconium dibutyl phosphate.

Zirconium /Infrared spectra/TBP/Fuel reprocessing /Degradation SummaryThe retention of zirconium in 30% TBP/nDD as a function of the age of zirconium organic solutions was studied by observing spectra in the infrared region of 3700 cm" 1 to 220 cm" 1 . Fourier Transform infrared spectra of the system zirconium/nitric acid/ tributyl phosphate /n-dodecane and its components are presented along with assignment of the functional groups. During four months of aging, no new absorption bands developed in the spectra of zirconium tributyl phosphate/n-dodecane solutions. Zirconium that precipitated from aged organic solutions exhibited an infrared spectrum that was almost identical with the spectrum of zirconium nitrate dibutyl phosphate.

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