Showing papers in "Industrial & Engineering Chemistry Process Design and Development in 1963"

Holdup Studies in a Pulsed Sieve-Plate Solvent Extraction Column

Abstract: The total holdup of dispersed organic phases in a pulsed sieve-plate solvent extraction column was intensively studied in one-column geometry to determine the actual phase velocities. The column was 2 inches in diameter and contained 43 plates with a 2-inch plate spacing. The plates were made of 19- gage, Type 304 stninless steel perforated with 1/8-inch-diameter holes to give a 23% free area. Hexane, benzene, and methyl isobutyl ketone were used as the individual dispersed phases with water as the continuous phase. The effects of pulse amplitude, phase flow rates, and pulsation frequency on the dispersed phase holdup were studied. Dispersed phase holdup was found to be a minimum at the transition frequency between mixer-settler and exaulsion types of column operation. For the system studied, this frequency can be predicted from a simple empirical correlation. The results have been used in the analysis of continuous phase longitudinal mixing data to be reported later. (auth)

Polymeric Ligands. Separation of Uranium from Solutions and Ore Leaches with Salicylic Acid-Formaldehyde Polymers

Abstract: Uranium is extracted as uranyl ion from solutions, using salicylic acid- formaidehyde polymers. Use of the technique described gave uranium of good purity in high yields. (auth)

Plutonium metal from trifluoride

Abstract: Plutonium trifluoride can be precipitated from a plutonium(III) nitrate solution, dried, and reduced to metal using calcium with an iodine booster. This system, with variations, has been in routine use at the Savannah River Plant for several years to produce 2000-gram buttons of plutonium metal. Criteria that determine crystal size and filtrate loss during precipitation in a two-stage unit appear applicable to the design and operation of multistage units for the precipitation of other compounds. The low heat of reduction of the trifluoride requires 0.6 mole of iodine per mole of plutonium as a booster for good yields. Problems caused by iodine are eliminated by oxidizing anhydrous PuFg with dry oxygen to a mixture of PuF/su 4/ and PuO/sub 2/, which has sufficient heat of reduction to be reduced with calcium alone, in 96% yield. General relationships between plutonium fluorides and oxides, the role of hydrated tetrafluorides, and filtrate recovery are discussed. (auth)

Solvent Extraction Recovery and Purification of Strontium-90

Abstract: A solvent extraction process was developed to produce high-purity Sr/sup 90/ from an irradiated U reprocessing waste solutlon. The extractant is D2EHPA diluted with TBP and Shell Spray Base. The process uses an acetic acid-acetate huffered aqueous phsse which is countercurrently contracted with the D2EHPA organic phase. Calcium and some Ce/sup 144/ extract with the Sr/sup 90/; extraction of other contaminants (Zr/sup 95/, Nb/sup 95/, Ru/sup 106/, and inert lead and iron) is prevented by adding either DTPA or EDTA to the feed solution. Decontamination from Ca and Ce/sup 144/ is provided by back extraction of the Sr/ sup 90/ into an aqueous 1M citric acid solution. The process was used to isolate and purify about one megacurie of Sr/sup 90/ for subsequent use in the fabrication of thermoelectric power generators as part of the Systems for Nuclear Auxiliary Power (SNAP) program. (auth)

Mutual Separation of Yttrium-91 and Promethium-147 by Countercurrent Solvent Extraction in Pulse Column

Abstract: Continuous solvent extraction was proved satisfactory in separating Y/ sup 91/ from Pm/sup 147/, using synthetic mixtures of the pair of nuclides. The separation was conducted in a compound perforated plate pulse column using 10% di(2-ethyl hexyl) phosphoric acid in toluene against an aqueous solution of HNO/ sub 3/. One column volume change per hour was realized by appropriate choice of flow rates. Pulse frequency was maintained at 50 cycles per minute and pulse amplitude at 1 cm. The Pm: Y ratio in the feed was varied from 0.08 to 135. Pm in excess of 99% and Y in excess of 97% purity were obtained. Steady state was reached in 12 hours. The approach to steady state was the same for any one component in all runs conducted, but was much slower than that predicted by calculations reported in the literature for discrete stages. (auth)

Multicycle Reprocessing and Refabrication Experiments on Sintered UO2-Fissia Pellets

Abstract: A multicycle reprocessing and refabrication scheme was simulated (using UO/sub 2/ spiked'' with fissia) to evaluate the feasibility of refabricating high-burnup UO/sub 2/ to a cumulative level of 10/sup 5/ Mwd/MTU. Various powder characteristics were studied, using oxidation-reduction methods as the reprocessing scheme. Processing conditions were established for the multicycle tests. Fissia, typical fission products (mostly oxides), were added to the reprocessed powder prior to compacting operations. There should be no difficulty in refabricating pellets from high-burnup material; conversely, the sinterability of UO/sub 2/ containing comparatively iarge concentrations of fissia is even enhanced. Well-formed pellets of density near 98% of theoretical were made for simulated burnups of 60,000, 80,000, and 100,000 Mwd/MTU. Cesium was the only fission element removed during processing.