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Spectrophotometric Determination of Cerium With Tiron

Description: A spectrophotometric method for the determination of cerium and Tiron (disodium-1,2-dihydroxybenzene-3,5disulfonate) was applied to the determination of cerium in samples which contain uranium and zirconium. The ceriumTiron complex in solutions of pH 8 or greater exhibits an absorption maximum of 500 m mu . This reagent does not react with any other lanthanive element. The interference of iron, uranium, and zirconium was eliminated by extracting these interfering elements with a solution of trioctylphosphine oxide in cyclohexane. (auth)
Date: June 14, 1957
Creator: McDowell, B. L.; Meyer, A. S., Jr. & White, J. C.
Partner: UNT Libraries Government Documents Department

DIRECT SPECTROPHOTOMETRIC DETERMINATION OF URANIUM IN CYCLOHEXANE SOLUTIONS OF TRI-n-OCTYLPHOSPHINE OXIDE

Description: A method for the direct determination of uranium in a cyclohexane solution of tri-n-octylphosphine oxide (TOPO) is presented. The adduct, UO/sub 2/ Cl/sub 2/ x 2TOPO, that is formed when uranium(VI) is extracted from hydrochloric acid solutions by tri-n-octylphosphine oxide absorbs light in the ultraviolet region. This absorbance is measured at 230 m mu vs. a TOPO-cyclohexane solution that was contacted with hydrochloric acid of the same concentration as that in the test aliquot. The molar absorbance index is 5500. The method is not selective; of the elements that are extracted by TOPO from hydrochloric acid, iron(III), zirconium, molybdenum, tin and thorium, only thorium can be tolerated. (auth)
Date: April 21, 1959
Creator: White, J. C.
Partner: UNT Libraries Government Documents Department

Automated fluorometer for uranium analysis

Description: An utomated fluorometer has proven to be a valuable analytical tool for analyzing natural waters for the Uranium Resource Evaluation (URE) project. Uranium is isolated from potential quenching ions and concentrated by extraction with tri-n-octylphosphine oxide (TOPO) in Varsol. A portion of the extract is placed on a sodium fluoride pellet which is then dried, sintered, and cooled. Sixteen samples can be analyzed in about 1.5 hours. The lower reporting limit has been set at 0.20 micrograms per liter (..mu..g/l).
Date: March 1, 1978
Creator: McElhaney, R. J.; Caylor, J. D.; Cole, S. H.; Futrell, T. L. & Giles, V. M.
Partner: UNT Libraries Government Documents Department

THE USE OF TRI-n-OCTYLPHOSPHINE OXIDE IN THE SOLVENT EXTRACTION OF THORIUM FROM ACIDIC SOLUTIONS

Description: Thorium is readily extracted by a solution of tri-noctylphosphine oxide in cyclohexane from either acidic nitrate or chloride solutions. The maximum extraction coefficient in a nitrate medium is 380 as compared to 1300 for a chloride solution. In nitrate media the extraction coefficient is relativelv unaffected by changes in the anion concentration. In chloride media the coefficient varies directly with increasing chloride concentration, i.e., from about 0.4 in one molar chloride to the maximum in 7 to 10 molar. The acid concentration should be at least one molar. Thorium is not appreciably extracted from sulfate solutions. The extraction coefficient is of the order of 0.3. The addition of nitrate or chloride increases the coefficient sufficiently so that essentially 99% of the thorium can be extracted in a single equilibration. In perchlolate systems the extractlon is most efficient in one molar acid. The maximum (The above was unscabble material)
Date: November 20, 1958
Creator: Ross, W.J. & White, J.C.
Partner: UNT Libraries Government Documents Department

Actinide removal from nitric acid waste streams

Description: Actinide separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve plutonium secondary recovery and americium removal from nitric acid waste streams generated by plutonium purification operations. Capacity and breakthrough studies show anion exchange with Dowex 1x4 (50 to 100 mesh) to be superior for secondary recovery of plutonium. Extraction chromatography with TOPO(tri-n-octyl-phosphine oxide) on XAD-4 removes the final traces of plutonium, including hydrolytic polymer. Partial neutralization and solid supported liquid membrane transfer removes americium for sorption on discardable inorganic ion exchangers, potentially allowing for non-TRU waste disposal.
Date: January 1, 1986
Creator: Muscatello, A.C. & Navratil, J.D.
Partner: UNT Libraries Government Documents Department

Hybrid chemical and nondestructive-analysis technique

Description: A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities.
Date: January 1, 1982
Creator: Hsue, S.T.; Marsh, S.F. & Marks, T.
Partner: UNT Libraries Government Documents Department

Uranium from phosphate ores

Description: Phosphate rock, the major raw material for phosphate fertilizers, contains uranium that can be recovered when the rock is processed. This makes it possible to produce uranium in a country that has no uranium ore deposits. The author briefly describes the way that phosphate fertilizers are made, how uranium is recovered in the phosphate industry, and how to detect uranium recovery operations in a phosphate plant. Uranium recovery from the wet-process phosphoric acid involves three unit operations: (1) pretreatment to prepare the acid; (2) solvent extraction to concentrate the uranium; (3) post treatment to insure that the acid returning to the acid plant will not be harmful downstream. There are 3 extractants that are capable of extracting uranium from phosphoric acid. The pyro or OPPA process uses a pyrophosphoric acid that is prepared on site by reacting an organic alcohol (usually capryl alcohol) with phosphorous pentoxide. The DEPA-TOPO process uses a mixture of di(2-ethylhexyl)phosphoric acid (DEPA) and trioctyl phosphine oxide (TOPO). The components can be bought separately or as a mixture. The OPAP process uses octylphenyl acid phosphate, a commercially available mixture of mono- and dioctylphenyl phosphoric acids. All three extractants are dissolved in kerosene-type diluents for process use.
Date: January 1, 1983
Creator: Hurst, F.J.
Partner: UNT Libraries Government Documents Department

Polonium-210 assay using a background-rejecting extractive liquid-scintillation method

Description: This paper describes a procedure which combines solvent extraction with alpha liquid scintillation spectrometry. Pulse shape discrimination electronics are used to reject beta and gamma pulses and to lower the background count to acceptable levels. Concentration of /sup 210/Po and separation from interferring elements are accomplished using a H/sub 3/Po/sub 4/-HCl solution with TOPO combined with a scintillor in toluene. (DLC)
Date: January 1, 1981
Creator: Case, C.N. & McDowell, W.J.
Partner: UNT Libraries Government Documents Department

Hybrid chemical and nondestructive analysis technique

Description: A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities.
Date: January 1, 1983
Creator: Hsue, S.T.; Marsh, S.F. & Marks, T.
Partner: UNT Libraries Government Documents Department

Recovery of protactinium-231 and thorium-230 from cotter concentrate: pilot plant operatins and process development

Description: The equipment and methods used to recover and purify 339 g of thorium-230 and 890 mg of protactinium-231 from 22 of the 1251 drums of Cotter Concentrate are described. The process developed was (1) dissolution at 100/sup 0/C in concentrated nitric acid and dilution to 2 to 3 molar acid, (2) filtration to remove undissolved solids (mostly silica filter aid), (3) extraction of uranium with di-sec-butyl-phenyl phophonate (DSBPP) in carbon tetrachloride, (4) extraction of both thorium and protactinium with tri-n-octylphosphine oxide (TOPO) in carbon tetrachloride followed by selective stripping of the thorium with dilute of sulfuric acid, (5) thorium purification using oxalic acid, (6) stripping protactinium from the TOPO with oxalic acid, and (7) protactinium purification through a sequence of steps. The development of the separation procedures, the design of the pilot plant, and the operating procedures are described in detail. Analytical procedures are given in an appendix. 8 figures, 4 tables.
Date: February 10, 1983
Creator: Hertz, M.R.; Figgins, P.E. & Deal, W.R.
Partner: UNT Libraries Government Documents Department

Identification and separation of the organic compounds in coal-gasification condensate waters. [5,5 dimethyl hydantoin, dihydroxy benzenes, acetonitrile]

Description: A substantial fraction of the organic solutes in condensate waters from low-temperature coal-gasification processes are not identified by commonly employed analytical techniques, have low distriution coefficients (K/sub C/) into diisopropyl ether (DIPE) or methyl isobutyl ketone (MIBK), and are resistant to biological oxidation. These compounds represent an important wastewater-treatment problem. Analytical techniques were developed to detect these polar compounds, and the liquid-liquid phase equilibria were measured with several solvents. A high-performance liquid - chromatography (HPLC) technique was employed to analyze four condensate-water samples from a slagging fixed-bed gasifier. A novel sample-preparation technique, consisting of an azeotropic distillation with isopropanol, allowed identification of compounds in the HPLC eluant by combined gas chromatography and mass spectrometry. 5,5-dimethyl hydantoin and related compounds were identified in condensate waters for the first time, and they account for 1 to 6% of the chemical oxygen demand (COD). Dimethyl hydatoin has a K/sub D/ of 2.6 into tributyl phosphate (TBP) and much lower K/sub D/ values into six other solvents. It is also resistant to biological oxidation. Phenols (59 to 76% of the COD), dihydroxy benzenes (0.02 to 9.5% of the COD), and methanol, acetonitrile, and acetone (15% of the COD in one sample) were also detected. Extraction with MIBK removed about 90% of the COD. MIBK has much higher K/sub D/ values than DIPE for dihydroxy benzenes. Chemical reactions occurred during storage of condensate-water samples. The reaction products had low K/sub D/ values into MIBK. About 10% of the COD had a K/sub D/ of nearly zero into MIBK. These compounds were not extracted by MIBK over a wide range of pH. 73 references, 6 figures, 35 tables.
Date: August 1, 1983
Creator: Mohr, D.H. Jr. & King, C.J.
Partner: UNT Libraries Government Documents Department

Separation techniques for the clean-up of radioactive mixed waste for ICP-AES/ICP-MS analysis

Description: Two separation techniques were investigated for the clean-up of typical radioactive mixed waste samples requiring elemental analysis by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) or Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). These measurements frequently involve regulatory or compliance criteria which include the determination of elements on the EPA Target Analyte List (TAL). These samples usually consist of both an aqueous phase and a solid phase which is mostly an inorganic sludge. Frequently, samples taken from the waste tanks contain high levels of uranium and thorium which can cause spectral interferences in ICP-AES or ICP-MS analysis. The removal of these interferences is necessary to determine the presence of the EPA TAL elements in the sample. Two clean-up methods were studied on simulated aqueous waste samples containing the EPA TAL elements. The first method studied was a classical procedure based upon liquid-liquid extraction using tri-n- octylphosphine oxide (TOPO) dissolved in cyclohexane. The second method investigated was based on more recently developed techniques using extraction chromatography; specifically the use of a commercially available Eichrom TRU[center dot]Spec[trademark] column. Literature on these two methods indicates the efficient removal of uranium and thorium from properly prepared samples and provides considerable qualitative information on the extraction behavior of many other elements. However, there is a lack of quantitative data on the extraction behavior of elements on the EPA Target Analyte List. Experimental studies on these two methods consisted of determining whether any of the analytes were extracted by these methods and the recoveries obtained. Both methods produced similar results; the EPA target analytes were only slightly or not extracted. Advantages and disadvantages of each method were evaluated and found to be comparable.
Date: March 17, 1993
Creator: Swafford, A.M. & Keller, J.M.
Partner: UNT Libraries Government Documents Department

Recovery and purification of nickel-63 from HFIR-irradiated targets

Description: The production of large quantities of high-specific-activity [sup 63]Ni (>10 Ci/g) requires both a highly enriched [sup 62]Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at [sup 51]Cr, and scandium, present as [sup 46]Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.
Date: June 1, 1993
Creator: Williams, D.F.; O'Kelley, G.D.; Knauer, J.B.; Porter, C.E. & Wiggins, J.T.
Partner: UNT Libraries Government Documents Department