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Analytical Method for Inline Plutonium Analyses

Description: Laboratory studies demonstrated the feasibility of a colorimetric method for the in-line analysis of plutonium(III) and plutonium(IV) in the Purex process. Negligible interference was caused by normal variations in the concentration of nitric acid, nitrous acid, or ferric sulfate. (auth)
Date: August 1, 1961
Creator: Overman, R. F.
Partner: UNT Libraries Government Documents Department


Description: We propose a process that uses sulfur dioxide from coal combustion as a raw material to synthesize polymeric ferric sulfate (PFS), a water treatment agent. The process uses sodium chlorate as an oxidant and ferrous sulfate as an absorbent. The major chemical mechanisms in this reaction system include oxidation, hydrolysis, and polymerization. Oxidation determines sulfur conversion efficiency while hydrolysis and polymerization control the quality of product. Many factors, including SO{sub 2} inlet concentration, flow rate of simulated flue gas, reaction temperature, addition rate of oxidant and stirring rate, may affect the efficiencies of SO{sub 2} removal. Currently, the effects of SO{sub 2} inlet concentration, the flow rate of simulated flue gas and addition rate of flue gas on removal efficiencies of SO{sub 2}, are being investigated. Experiments shown in this report have demonstrated that the conversion efficiencies of sulfur dioxide with ferrous sulfate as an absorbent are in the range of 60-80% under the adopted process conditions. However, the conversion efficiency of sulfur dioxide may be improved by optimizing reaction conditions to be investigated. Partial quality indices of the synthesized products, including Fe{sup 2+} concentration and total iron concentration, have been evaluated.
Date: December 1, 2001
Creator: Brown, Robert C. & Fan, Maohong
Partner: UNT Libraries Government Documents Department

Exploratory coprocessing research. Quarterly report Number 9, September 1--November 30, 1990

Description: The objectives of this project are to: (1) study the scope of hydrothermal pretreatment of coal on subsequent conversion, (2) identify and study the chemical or physical causes of this effect, and (3) attempt to elucidate the chemistry responsible for any coal-resid synergisms. This project is divided into three tasks. This quarter the authors concentrated on Tasks 2 and 3 as described below. Task 2: chemistry of pretreatment. This Quarter they continued their investigation of the chemistry of pretreatment using an iron catalyst, (ferrous sulfate), both with and without aqueous pretreatment on Wyodak coal. The combination of iron and hydrothermal pretreatment gave the best results, as long as the pretreated coal was not dried prior to conversion. However, the combination of iron and pretreatment gave similar conversions as with pretreatment alone. Task 3: chemistry of synergy. To help provide a baseline for distinguishing between the benefits resulting from chemical and physical solvency factors, the authors decided to conduct some experiments in homogeneous systems, from which they can easily extract the impact due to chemical changes. They synthesized a series of benzyl aromatics and studied their cleavage in a mixture of anthracene and dihydroanthracene. Cleavage rates for the different substrates increase in the order diphenylmethane < benzylnaphthalene < benzylphenanthrene < benzylpyrene. The log of observed first-order rate constants correlate linearly with the exothermicity of H-addition to the aromatic bearing the benzyl group, and are in excellent agreement with previously modeled results. The experimental results further show the generality of induced bond cleavage, and buttress the view of the possible chemical basis of improvements resulting from increased aromaticity.
Date: May 1, 1991
Creator: Hirschon, A.S.; Tse, D.T.; Malhotra, R.; McMillen, D.F. & Ross, D.S.
Partner: UNT Libraries Government Documents Department

Extracellular iron-sulfur precipitates from growth of Desulfovibrio desulfuricans

Description: The authors have examined extracellular iron-bearing precipitates resulting from the growth of Desulfovibrio desulfuricans in a basal medium with lactate as the carbon source and ferrous sulfate. Black precipitates were obtained when D. desulfuricans was grown with an excess of FeSO{sub 4}. When D. desulfuricans was grown under conditions with low amounts of FeSO{sub 4}, brown precipitates were obtained. The precipitates were characterized by iron K-edge XAFS (X-ray absorption fine structure), {sup 57}Fe Moessbauer-effect spectroscopy, and powder X-ray diffraction. Both were noncrystalline and nonmagnetic (at room temperature) solids containing high-spin Fe(III). The spectroscopic data for the black precipitates indicate the formation of an iron-sulfur phase with 6 nearest S neighbors about Fe at an average distance of 2.24(1) {angstrom}, whereas the brown precipitates are an iron-oxygen-sulfur phase with 6 nearest O neighbors about Fe at an average distance of 1.95(1) {angstrom}.
Date: December 20, 1999
Creator: Antonio, M. R.; Tischler, M. L. & Witzcak, D.
Partner: UNT Libraries Government Documents Department

Moessbauer investigation of materials used in Sandia`s DCL catalyst testing program

Description: Moessbauer spectroscopy has been used to determine the iron-bearing phases in the coal, catalysts, and IOM products used and generated in the Direct Coal Liquefaction (DCL) catalyst testing program at Sandia National Laboratories, New Mexico. DCL experiments were conducted with a Blind Canyon, Utah, coal both thermally and with three different iron-based catalysts: (1) a sulfated hematite catalyst (Fe{sub 2}O{sub 3}/SO{sub 4}{sup 2{minus}}), (2) a 6-line ferrihydrite catalyst, and (3) iron-oxide impregnated directly into coal. The catalysts were added to the coal at both a 0.5 and a 1.0 wt% level and sufficient sulfur was added to ensure complete sulfidation of the iron. The Moessbauer spectrum of the Blind Canyon coal revealed that the major iron-bearing mineral present was ankerite, Ca(Fe,Mg)(CO{sub 3}){sub 2}, which converts firs to {gamma}-Fe (austenitic iron) before undergoing partial sulfidation to pyrrhotite in the thermal runs. The percentages of pyrrhotite formed in the catalytic runs were higher than those in the thermal runs indicating that sulfidation of the added iron occurs more rapidly than with the ankerite. Moessbauer data on the amount of pyrrhotite present does not correlate well with THF and heptane conversion percentages, indicating that other parameters like catalyst dispersion must also be considered.
Date: July 1, 1996
Creator: Rao, K.R.P.M.; Huggins, F.E.; Huffman, G.P. & Stohl, F.V.
Partner: UNT Libraries Government Documents Department


Description: Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. Characterizations of dry PFS synthesized from SO{sub 2} show the PFS possesses amorphous structure, which is desired for it to be a good coagulant in water and wastewater treatment. A series of lab-scale experiments were conducted to evaluate the performance of PFS synthesized from waste sulfur dioxide, ferrous sulfate and sodium chlorate. The performance assessments were based on the comparison of PFS and other conventional and new coagulants for the removal of turbidity and arsenic under different laboratory coagulant conditions. Pilot plant studies were conducted at Des Moines Water Works in Iowa and at the City of Savannah Industrial and Domestic (I&amp;D) Water Treatment Plant in Port Wentworth, Georgia. PFS performances were compared with those of conventional coagulants. The tests in both water treatment plants have shown that PFS is, in general, comparable or better than other coagulants in removal of turbidity and organic substances. The corrosion behavior of polymeric ferric sulfate (PFS) prepared from SO{sub 2} and ferric chloride (FC) were compared. Results showed that ...
Date: November 1, 2004
Creator: Brown, Robert C.; Fan, Maohong & Cooper, Adrienne
Partner: UNT Libraries Government Documents Department


Description: Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. The PFS product was used in pilot-scale tests at a municipal water treatment facility and gave good results in removal of turbidity and superior results in removal of disinfection byproduct precursors (TOC, DOC, UV-254) when compared with equal doses of ferric chloride.
Date: October 1, 2002
Creator: Brown, Robert C.; Fan, Maohong & Cooper, Adrienne
Partner: UNT Libraries Government Documents Department


Description: The objective of this NETL sponsored bench-scale study was to demonstrate the efficacy of enhanced anaerobic reductive precipitation (EARP) technology for precipitating uranium using samples from contaminated groundwater at the Fernald Closure Project (FCP) in Cincinnati, Ohio. EARP enhances the natural biological reactions in the groundwater through addition of food grade substrates (typically molasses) to drive the oxidative-reductive potential of the groundwater to a lower, more reduced state, thereby precipitating uranium from solution. In order for this in-situ technology to be successful in the long term, the precipitated uranium must not be re-dissolved at an unacceptable rate once groundwater geochemical conditions return to their pretreatment, aerobic state. The approach for this study is based on the premise that redissolution of precipitated uranium will be slowed by several mechanisms including the presence of iron sulfide precipitates and coatings, and sorption onto fresh iron oxides. A bench-scale study of the technology was performed using columns packed with site soil and subjected to a continuous flow of uranium-contaminated site groundwater (476 {micro}g/L). The ''treated'' column received a steady stream of dilute food grade molasses injected into the contaminated influent. Upon attainment of a consistently reducing environment and demonstrated removal of uranium, an iron sulfate amendment was added along with the molasses in the influent solution. After a month long period of iron addition, the treatments were halted, and uncontaminated, aerobic, unamended water was introduced to the treated column to assess rebound of uranium concentrations. In the first two months of treatment, the uranium concentration in the treated column decreased to the clean-up level (30 {micro}g/L) or below, and remained there for the remainder of the treatment period. A brief period of resolubilization of uranium was observed as the treated column returned to aerobic conditions, but the concentration later returned to below the clean-up ...
Date: August 1, 2003
Creator: Lutes, Christopher C.; Angela Frizzell, PG; Thornton, Todd A. & Harrington, James M.
Partner: UNT Libraries Government Documents Department

Coal liquefaction process streams characterization and evaluation: Investigation of the forms of sulfur in five Wilsonville resid samples by XAFS and moessbauer spectroscopy

Description: This study demonstrated the feasibility of using XAFS and Moessbauer spectroscopy for the examination of distillation resid materials derived from direct coal liquefaction. The least-squares analysis of the XANES region of the K-shell XAFS spectra was shown to be technique which can be used to determine the sulfur forms in coal liquefaction-derived resid samples. The large amount of pyrrhotite in the resid samples (71 to 99% {plus_minus}10% of the total sulfur) interfered with the precise quantitative analysis of the organic sulfur. However, a spectral subtraction routine was successfully used to provide semi-quantitative results for sulfur species other than the pyrrhotite. Moessbauer spectroscopy, considered a more accurate method than XAFS for the quantitative analysis of inorganic iron-sulfur species (pyrite, pyrrhotite, iron sulfates), was successfully used to speciate these materials in the coal liquefaction resids. Further application of XAFS and Moessbauer spectroscopy as process development tools appears justified by these results.
Date: November 1, 1992
Creator: Huffman, G. P.; Huggins, F. E. & Shah, N.
Partner: UNT Libraries Government Documents Department

Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Technical report, December 1, 1992--February 28, 1993

Description: The purpose of this project are to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE process developed by the Midwest Ore Processing Co.(MWOPC), to verify the forms-of-sulfur determination using the ASTM method for evaluation of the PCE process, and to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. The objectives for year-2 study are to verify the possible effect of PCE treatment on coal-derived FeS{sub 2}, FeSO{sub 4}, and Fe{sub 2}(SO{sub 4}){sub 3} on ASTM coal analysis, to investigate the behavior of sulfur during oxidation and PCE desulfurization using the isotopically signatured coal sample to investigate the proprietary reagent on the oxidation of the organic sulfur model compounds with and without additives, to evaluate this new oxidation on the organic sulfur removal by PCE desulfurization, and to study other innovative pretreatment processes for the removal of organic sulfur from coal under mild conditions. Oxidation study on the organosulfur model compounds alone was completed in first quarter. The oxidation reactions were repeated on the organosulfur model compounds with the presence of hydrocarbon additives. These additives are known to easily produce hydroperoxides during air oxidation. Analysis of the reaction products is in progress.
Date: May 1, 1993
Creator: Chou, M. I. M.; Lytle, J. M.; Ruch, R. R.; Kruse, C. W.; Chaven, C.; Hackley, K. C. et al.
Partner: UNT Libraries Government Documents Department

Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, October 1994--December 1994

Description: Coal liquefaction involves cleavage of methylene and dimethylene and ether-type bridges connecting polycyclic aromatic units. The selected compounds for model coal liquefaction reactions are 4-(l-naphthylmethyl)bibenzyl (NMBB) and several oxygen-containing compounds. This report mainly describes the synthesis and screening of selected iron and molybdenum compounds as precursors of dispersed catalysts for hydrocracking of NMBB and oxygen-containing compounds. Experiments using NMBB were carried out at 400{degrees}C for 30 min. under 6.9 MPa H{sub 2} pressure. All catalyst precursors converted NMBB predominately into naphthalene and 4-methylbibenzyl. Generally, ferrocene demonstrated very low activity as catalyst. Even sulfur addition did not increase activity. Hydrated iron sulfate FeSO{sub 4} x 7 H{sub 2}O gave similar conversion like ferrocene. In order to clarify the effect of sulfur alone on model compound conversion, NMBB was treated with sulfur in concentrations of 1.2 to 3.4 wt %, corresponding to conditions present in catalytic runs with sulfur. It was found that increasing sulfur concentrations lead to higher NMBB conversion. Furthermore, sulfur had a permanent influence on the reactor walls. It reacted with the transition metals in the steel to form a microscopic black iron sulfide layer on the surface, which could not be removed mechanically. Non catalytic runs after experiments with added sulfur yielded higher conversion than a normal run with a new reactor. The objective of the work on oxygen-compounds is to investigate the utility of highly dispersed catalysts, from organometallic precursors, in the removal of heteroatom functionality from the products of a reaction performed under liquefaction conditions. The bimetallic catalytic precursor CoMo-T2 exhibited a sizable increase in the yield of non-O-containing products, compared to the run using a standard inorganic catalyst precursor (ATTM) or a non-catalytic reaction.
Date: February 1995
Creator: Schmidt, E.; Kirby, S. & Song, Chunshan
Partner: UNT Libraries Government Documents Department


Description: A scavenging-precipitation ion-exchange process using phenolic resins was developed to decontaminate lowradioactivity-level process water waste prior to discharge to the environment. In laboratory and small engineeringscale tests, greater than 99.9% of the cesium and strontium, the principal biological hazards were removed from ORNL low-level waste, and the total activity level was lowered to less than the maximum permissible concentration recommended for populations in the neighborhood of atomic energy installations. The water was treated by a scavenging-precipitation with sodium hydroxide, pH 11.7, and ferrous sulfate, copperas-5 ppm Fe, to remove suspended solids and soluble hardness, clarified, and then passed through a carboxylic-phenolic ion-exchange resin to sorb the remaining radionuclides. After passage of 1,500 to 2,000 resin-bed volumes, the resin was eluted with 10 volumes of 0.5 M HNO/sub 3/. Sodium carbonate can be added in the precipitation step to aid the quantitative precipitation of calcium for wastes that contain small amounts of phosphates, or alternatively, an extra ion-exchange column of carboxylic resin can be used to remove calcium and thus conserve the capacity of the phenolic resin for cesium and strontium. Three kinds of studies were made: batch laboratory-scale studies, continuous nonradioactive runs at 15 liters/hr, and runs with radioactive waste at 60 liters/ hr. These studies led to a pilot-plant demonstration of the process. The process is similar to that reported in ORNL-3036, which describes the use of a sulfonic-phenolic resin and a 5 M HCl regenerant. (auth)
Date: July 10, 1963
Creator: Holcomb, R.R.
Partner: UNT Libraries Government Documents Department

Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

Description: Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} &lt; 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.
Date: March 15, 2008
Creator: Seol, Yongkoo & Javandel, Iraj
Partner: UNT Libraries Government Documents Department

Froth flotation of oil-bearing metal sulfide wastes

Description: An industrial wastewater, including plating wastes, is treated with sodium sulfide and ferrous sulfate to form a sulfide-oxide precipitate containing chromium and other toxic metals. Hydrocarbons, in the water, coat the sulfide-oxide particles, impeding metal recovery. Froth flotation, without reagent addition, was found to recover 93.9% of the solids from the sludge with simultaneous rejection of 89% of the water. Methyl isobutyl carbinol (MIBC) improved recovery and potassium amyl xanthate improved both recovery and grade. The process design has wastewater feed (without MIBC) to the rougher circuit. The rougher concentrate is conditioned with MIBC and fed to a cleaner circuit to achieve a high grade concentrate. About 95% of the water is recirculated to the waste treatment plant. 3 refs., 3 figs., 4 tabs.
Date: December 1, 1991
Creator: Miller, R. L.; Atwood, R. L. & Ye, Yi
Partner: UNT Libraries Government Documents Department

H{sub 2}S-removal and sulfur-recovery processes using metal salts

Description: Scrubbing a sour gas stream with a solution of copper sulfate allows the clean-up temperature to be increased from ambient to the adiabatic saturation temperature of the gas. The copper ion in solution reacts with the H{sub 2}S to produce insoluble CuS. The choice of copper sulfate was set by the very low solubility of CuS and the very rapid kinetics of the Cus formation. Since the copper sulfate solutions used are acidic, CO{sub 2} will not be co-absorbed. In a subsequent step the solid CuS is oxidized by a solution of ferric sulfate. The copper sulfate is regenerated, and elemental sulfur is formed together with ferrous sulfate. The ferrous sulfate is reoxidized to ferric sulfate using air. Since the copper sulfate and ferric solutions are regenerated, the overall reaction in this process is the oxidation of hydrogen sulfide with oxygen to form sulfur. The use of copper sulfate has the further advantage that the presence of sulfuric acid, even as concentrated as 1 molar, does not inhibit the sorption of H{sub 2}S. Furthermore, the absorption reaction remains quite favorable thermodynamically over the temperature range of interest. Because the reaction goes to completion, only a single theoretical stage is required for complete H{sub 2}S removal and cocurrent gas/liquid contacting may be employed. The formation of solids precludes the use of a packed column for the contacting device. However, a venturi scrubber would be expected to perform satisfactorily. The kinetics of the oxidation of metal sulfides, in particular zinc and copper sulfide, is reported in the literature to be slow at near-ambient temperatures. The proposed process conditions for the oxidation step are different from those reported in the literature, most notably the higher temperature. The kinetics of the reaction must be studied at high temperatures and corresponding pressures. An important goal ...
Date: November 1, 1992
Creator: Lynn, S. & Cairns, E. J.
Partner: UNT Libraries Government Documents Department

Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings. Final report

Description: Fireside corrosion, caused by liquid alkali-iron trisulfates, has been an obstacle to higher steam temperatures and to efficient utilization of high-sulfur coals. Tests simulating the environment in the superheater bank of a pulverized-coal-fired boiler were conducted on several promising new alloys and claddings. Alloys were exposed to a variety of synthetic ash and simulated flue gas compositions at 650 and 700{degrees}C for times ranging up to 800 hours. Included in the testing program were new high-chromium/high-nickel alloys, modified commercial alloys, lean stainless steels (modified Type 316) clad with high-chromium/high-nickel alloys, and intermetallic aluminides. Thickness loss measurements indicated that resistance to attach improved with increasing chromium level. Silicon and aluminum were also helpful in resisting attack, while molybdenum was detrimental to the resistance of the alloys to attack. Three different attack modes were observed on the alloys tested. Alloys with low resistance to attack exhibited uniform wastage, while pitting was observed in more resistant alloys. In addition to surface fluxing by molten alkali-iron trisulfates, subsurface sulfur penetration and intergranular attack also occurred.
Date: August 1, 1991
Creator: Van Weele, S.
Partner: UNT Libraries Government Documents Department

Catalyst dispersion and activity under conditions of temperature- staged liquefaction. Technical progress report, July--September 1991

Description: The general objectives of this research are (1) to investigate the use of highly dispersed catalysts for the pretreatment of coal by mild hydrogenation, (2) to identify the active forms of catalysts under reaction conditions and (3) to clarify the mechanisms of catalysis. The ultimate objective is to ascertain if mild catalytic hydrogenation resulting in very limited or no coal solubilization is an advantageous pretreatment for the transformation of coal into transportable fuels. The experimental program will focus upon the development of effective methods of impregnating coal with catalysts, evaluating the conditions under which the catalysts are most active and establishing the relative impact of improved impregnation on conversion and product distributions obtained from coal hydrogenation.
Date: February 1, 1992
Creator: Davis, A.; Schobert, H. H.; Mitchell, G. D. & Artok, L.
Partner: UNT Libraries Government Documents Department


Description: The volume of H/sub 2/ evolved on dissolving screened nonroasted U- bearing scrap, slag, and liner in HCl were determined; the values were found to indicate the degree of removal of metallic particles by screening. Digestions of nonroasted plant-pulverized scrap with HNO/sub 3/, NaNO/sub 3/, or Fe/sub 2/(SO/ sub 4/)/sub 3/ in HCl and with HNO/sub 3/ or NaNO/sub 3/ in H/su b 2/SO/sub 4/ were not so effective as digestion with NaClO/sub 3/ in HCl. Doubling the free acid content and addition of FeSO/sub 4/ improved the efficiency of the latter digestion. Removal of CaF/sub 2/ from crude (NH/sub 4/)/sub 2/ UO/sub 4/ by solution of the uranate in acetic acid, HCl, or Hsub 2SO/sub 4/ was limited by slow filtration rates. (W.L.H.)
Date: July 20, 1951
Creator: Fleck, H.
Partner: UNT Libraries Government Documents Department