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EUROCHEMIC ASSISTANCE: CHEMICAL TECHNOLOGY DIVISION UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT, DECEMBER 1958. (SECTIONS 5.0, 6.0, 8.0)

Description: A study of the equiibrium sorption isotherms and rates of U sorption on Dowex 21K is in progress. Data which show the effects of uranium concentration in solution on resin loading are presented Fuel reprocessing experiments are reported in which efforts were made to reduce Cl- in Darex dissolver solution to < 350 ppm for the extraction phase. The best method of Cl/sup -/ reduction appears to be operation with a down draft condenser and an air sparge. A check- out dissolution min in the 6 in. glass dissolver with a prototype APPR fuel element is reported, and data on dissolution time and composition of reacted products are given. Data on filtration rates for Darex solutions expected in large-scale operations are tabulated, and graphs illustrating the effects of pressure drop and filter aids on filtering rates are presented. Tests on washing U from filter cakes indicate that U can be removed to any desired level. Viscosity, density. and boiling points as a function of temperature or pressure were determined for two Darex solvent extraction feed solutions; data are presented grahically, and results of chemical analyses are tabuated. Demonstation runs for Sulfex and Zirflex dejacketing flowsheets were made. Results indicate that parts of the Sulfex flowsheet map have to be changed to prevent core losses from fluoride contamination. Results from the Zirflex demonstration are being compiled. Design of the SRE decanning device was completed and sub mitted to vendors for bids; also the design of a prototype fuel bundle to serve as an inexpensive substitute in chopping and leaching studies is reported. Preliminary shearing studies with the 120 ton hydraulic Manco shear indicate that its usefulness is limited, and criteria for a large shear for spent fuel bundles are being written. Darex-type solvent extraction studies using hexane are reported, and U ...
Date: May 1, 1959
Creator: Shank, E M
Partner: UNT Libraries Government Documents Department

PROCESS DEVELOPMENT QUARTERLY REPORT. II. PILOT PLANT WORK

Description: Progress is reported on the gross solubility of U in digestions of Mallinokrodt feed materials, studies of variables affecting U purity in a TBP hexane extraction cycle, low-acid flowsheet for TBP--hexane extraction process based on a 440 g U/liter in lM HNO/sub 3/ digest liquor, hacking studies in the pilot plant pumperdecanter system, recovery of U from residues from the dingot process, lowering the H level in dingot metal, forging of dingot bar stock, dingot extrusion, fubrication of UO/sub 2/ fuel elements, and the determination of H content of derby and ingot metal. (W.L.H.)
Date: May 1, 1957
Creator: Kuhlman, N. ed.
Partner: UNT Libraries Government Documents Department

Recovery of semi-volatile organic compounds during sample preparation: Compilation for characterization of airborne particulate matter

Description: Semi-volatile compounds present special analytical challenges not met by conventional methods for analysis of ambient particulate matter (PM). Accurate quantification of PM-associated organic compounds requires validation of the laboratory procedures for recovery over a wide volatility and polarity range. To meet these challenges, solutions of n-alkanes (nC{sub 12} to nC{sub 40}) and polycyclic aromatic hydrocarbons PAHs (naphthalene to benzo[ghi]perylene) were reduced in volume from a solvent mixture (equal volumes of hexane, dichloromethane and methanol), to examine recovery after reduction in volume. When the extract solution volume reached 0.5 mL the solvent was entirely methanol, and the recovery averaged 60% for n-alkanes nC{sub 12} to nC{sub 25} and PAHs from naphthalene to chrysene. Recovery of higher MW compounds decreased with MW, because of their insolubility in methanol. When the walls of the flasks were washed with 1 mL of equal parts hexane and dichloromethane (to reconstruct the original solvent composition), the recovery of nC{sub 18} and higher MW compounds increased dramatically, up to 100% for nC{sub 22}-nC{sub 32} and then slowly decreasing with MW due to insolubility. To examine recovery during extraction of the components of the High Capacity Integrated Gas and Particle Sampler, the same standards were used to spike its denuders and filters. For XAD-4 coated denuders and filters, normalized recovery was &gt; 95% after two extractions. Recovery from spiked quartz filters matched the recovery from the coated surfaces for alkanes nC{sub 18} and larger, and for fluoranthene and larger PAHs. Lower MW compounds evaporated from the quartz filter with the spiking solvent. This careful approach allowed quantification of organics by correcting for volatility- and solubility-related sample preparation losses. This method is illustrated for an ambient sample collected with this sampler during the Texas Air Quality Study 2000.
Date: May 1, 2002
Creator: Swartz, Erick; Stockburger, Leonard & Gundel, Lara
Partner: UNT Libraries Government Documents Department

Liquid chromatographic fractionations of mixtures of polystyrene oligomers

Description: Oligomer mixtures of 800, 2200, and 4000 molecular weight polystyrene have been fractionated using silica and bonded phase columns under similar conditions of solvent gradient and flow rate. Using a hexane/tetrahydrofuran gradient, the silica and nitro phases were best in that they separated 41 and 43 oligomers, respectively. At the other extreme, a phenyl bonded phase column gave virtually no resolution using a water/THF gradient and a cyano bonded phase column, using the earlier hexane/tetrahydrofuran system, resolved only 10 oligomers. Amino and octadecyl bonded phase columns gave results intermediate between these two extremes. The strength of the solvent used to dissolve the sample was found to be of critical importance. Use of too good a sample solvent seriously degraded the attainable resolution. When number average and weight average molecular weights for an 800 molecular weight polystyrene sample were calculated from the oligomer distribution, the silica column gave values which were most consistent with those reported from other methods.
Date: May 24, 1980
Creator: Curtis, M A; Webb, J W; Warren, D C; Brandt, V O; Gerberich, F G; Raut, K B et al.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

Description: Initial synthesis work has focused on preparation of fine-particle iron-based compounds using an Fe(CO){sub 5} precursor. Fe(CO){sub 5} was chosen because of the liability of the carbonyl ligands with respect to substitution under either moderate thermal or photochemical reaction conditions. Six synthesis attempts have been carried out with Fe(CO){sub 5} using CS{sub 2} as the sulfur source; they are outlined here.
Date: May 21, 1991
Creator: Klein, M.T.
Partner: UNT Libraries Government Documents Department

THE DISTILLATION OF URANIUM HEXAFLUORIDE AND BROMINE PENTAFLUORIDE IN A 0.5- INCH-DIAMETER PACKED COLUMN

Description: The efficiency of a 0.5 in. dia packed column with 1/16 in. nickel helices for the separation of the binary system UF/sub 6/-- BrF/sub 5/ was investigated. Several distlllations were performed wlth the system methylcyclohexane and nheptane for purposes of callbration. For both systems, pressure-drop measurements at various flow rates were determined and the flooding rates were determined from these. Experiments to determlne the equilibrium time were also conducted with both the organic and inorganic systems used for calibration. The separation efficiency was calculated as Htu/sub g/. The flooding rates determined were 570 for methylcyclohexane, 2680 for uranlum hexafluoride, and 2200 lb/(hr) (ft//sup 2/) for bromine pentafluoride. Equilibrium times of 34 and 24 hr were found for the organic and inorganic systems, respectively. The Htu/sub g/ was found to be 1.2 in. for flows of 50 to 450 lb/(hr)(ft//sup 2/) for the organic system. The Htu/sub g/ for the inorganic system was 1.3 in. at flow rates above 285 lb/(hr)(ft/sup 2/) and was found to increase to almost 3 in. at flow rates below this. (P.C.H.)
Date: May 1, 1962
Creator: Ivins, R.O.
Partner: UNT Libraries Government Documents Department

Inhalation developmental toxicology studies: Teratology study of n-hexane in mice: Final report

Description: Gestational exposure to n-hexane resulted in an increase in the number of resorbed fetuses for exposure groups relative to the control group; however, the increases were not directly correlated to exposure concentration. The differences were statistically significant for the 200-ppM with respect to total intrauterine death (early plus late resorptions), and with respect to late resorptions for the 5000-ppM group. A small, but statistically significant, reduction in female (but not male) fetal body weight relative to the control group was observed at the 5000-ppM exposure level. There were no exposure-related increases in any individual fetal malformation or variation, nor was there any increase in the incidence of combined malformations or variations. Gestational exposure of CD-1 mice to n-hexane vapors appeared to cause a degree of concentration-related developmental toxicity in the absence of overt maternal toxicity, but the test material was not found to be teratogenic. This developmental toxicity was manifested as an increase in the number of resorptions per litter for all exposure levels, and as a decrease in the uterine: extra-gestational weight gain ratio at the 5000-ppM exposure level. Because of the significant increase in the number of resorptions at the 200-ppM exposure level, a no observable effect level (NOEL) for developmental toxicity was not established for exposure of mice to 200, 1000 or 5000-ppM n-hexane vapors. 21 refs., 3 figs., 9 tabs.
Date: May 1, 1988
Creator: Mast, T.J.; Decker, J.R.; Stoney, K.H.; Westerberg, R.B.; Evanoff, J.J.; Rommereim, R.L. et al.
Partner: UNT Libraries Government Documents Department