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Recovery of Uranium From Wet Process Phosphoric Acid: Final Report

Description: From abstract: "The state of reduction of wet process phosphoric acid determines largely the extractability of its uranium content. This report defines the economic relationships involved over a wide range of reduction of the acid. Reductant consumption, penalties and capital investment as well as solvent consumption are evaluated."
Date: October 1954
Creator: Quinn, Patrick J.
Partner: UNT Libraries Government Documents Department

The Reduction of Uranium(VI) by Ferrous Iron in Phosphoric Acid Solution: The Formal Electrode Potential of the U(IV)/(VI) Couple

Description: Abstract: The extent of the reduction of U(VI) by Fe(II) in phosphoric acid solution has been measured as a function of the phosphoric acid concentration (1.9-7.7M) and as a function of the Fe(II)/Fe(III) ratio. Kinetic measurements of the slow redox equilibrium involved conform to a first order rate law. The introduction of fluoride ion into these solutions considerably increases both the reaction rate and the extent of the reduction. The formal electrode potential of the U(IV)/(VI) couple, E'U₄,₆ has been estimated in the range 1.85-4.8M H₃PO₄, from measured E'Fe₂,₃ values in combination with the redox equilibrium data.
Date: 1953-06-1u
Creator: Baes, Charles F., Jr.
Partner: UNT Libraries Government Documents Department

Wet Chemical Oxidation of Organic Waste Using Nitric-Phosphoric Acid Technology

Description: Experimental progress has been made in a wide range of areas which support the continued development of the nitric-phosphoric acid oxidation process for combustible, solid organic wastes. An improved understanding of the overall process operation has been obtained, acid recovery and recycle systems have been studied, safety issues have been addressed, two potential final waste forms have been tested, preliminary mass flow diagrams have been prepared, and process flowsheets have been developed. The flowsheet developed is essentially a closed-loop system which addresses all of the internally generated waste streams. The combined activities aim to provide the basis for building and testing a 250-400 liter pilot-scale unit. Variations of the process now must be evaluated in order to address the needs of the primary customer, SRS Solid Waste Management. The customer is interested in treating job control waste contaminated with Pu-238 for shipment to WIPP. As a result, variations for feed preparation, acid recycle, and final form manufacturing must be considered to provide for simpler processing to accommodate operations in high radiation and contamination environments. The purpose of this program is to demonstrate a nitric-phosphoric acid destruction technology which can treat a heterogeneous waste by oxidizing the solid and liquid organic compounds while decontaminating noncombustible items.
Date: October 6, 1998
Creator: Pierce, R.A.
Partner: UNT Libraries Government Documents Department

Britz-Heidbrink Inc. Mini-CRADA, Powder Coating of Animal Enclosures

Description: The goal of this CRADA was to combine the powder coating material and application techniques and laboratory testing capabilities of FM and T with the manufacturing, real-world testing, and practical knowledge available to BHI in a limited study to determine if coated stainless steel would provide the durability needed to justify additional work in this area. The coating materials chosen had to have low reflectivity and be easily sanitized, non-toxic, pleasant in appearance, and durable for the lifetime of the stainless steel product. The materials also had to be capable of withstanding the daily abuse of animal contact, impact with walls or other hard surfaces, and exposure to a variety of lighting and climatic conditions. FM and T and BHI worked together to investigate coating materials that under normal conditions would be exposed, at least weekly, to 180 F to 260 F washing and sanitization procedures that include strong detergents and phosphoric acid. After a proper cleaning method for the bare panels was established, six different powder coatings were selected and tested. The coatings were selected for their known resistance to harsh chemicals. Sample panels of each coating passed 1000 hours of continuous salt fog exposure and 24-hour constant submersion in heated disinfectant solutions. Actual cage panels were then coated and installed in a high-pressure spray washer at a medical research facility for accelerated real-world testing. In the high-pressure spray washer, the panels received the equivalent of one year's exposure to harsh chemicals in one week. In addition to the exposure to the harsh sanitizing chemicals, the test panels never had a chance to get completely dry. In actual use, the panels would have been cleaned once a week and would have been essentially dry the rest of the time. Constant soak in wet conditions is one of the most ...
Date: January 4, 2000
Creator: Smith, M.D.
Partner: UNT Libraries Government Documents Department

Project "A" Final Summary Report

Description: Report discussing the results of Project "A," which had three main components: "Effect of P2O3 Concentration on the Distribution Coefficient for Uranium Between Crude Phosphoric Acid and O.P.P.A.," "Effect of Chloride Concentration in Phosphoric Acid on the Distribution Coefficient for Uranium Between O.P.P.A. and Phosphoric Acid," and "The Use of Di-Isobutyl Carbinol in the Preparation of a Solvent to Extract Uranium from Phosphoric Acid (N.P.P.A.)."
Date: January 4, 1954
Creator: Wilkinson, G. E.
Partner: UNT Libraries Government Documents Department

Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

Description: The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are approximately 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBP solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated options for absorbing HDBP from ...
Date: October 2, 1998
Creator: Pierce, R.A.
Partner: UNT Libraries Government Documents Department

Commercialization of fuel-cells

Description: This report is an abbreviated version of the ''Report of the DOE Advanced Fuel Cell Commercialization Working Group (AFC2WG),'' released January 1995. We describe fuel-cell commercialization for stationary power applications of phosphoric acid, molten carbonate, solid oxide, and polymer electrolyte membrane fuel cells.
Date: March 1, 1995
Creator: Penner, S.S.; Appleby, A.J.; Baker, B.S.; Bates, J.L.; Buss, L.B.; Dollard, W.J. et al.
Partner: UNT Libraries Government Documents Department

Solubility Limits of Dibutyl Phosphoric Acid in Uranium Solutions at SRS

Description: The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are {tilde 6} g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with DBP which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. SRTC tests have shown that U-DBP solids will precipitate at concentrations potentially attainable during storage of enriched uranium solutions. Evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if DBP concentration in the resulting solution exceeds 110 ppm at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. The most important variables of interest for present plant operations are HNO{sub 3} and DBP concentrations. Temperature is also an important variable controlling precipitation. The data obtained in these tests can be used to set operating and safety limits for the plant. It is recommended that the data for 0 degrees C with 0.5 M HNO{sub 3} be used for setting the limits. The limit would be 80 mg/L which is 3 standard deviations below the average of 86 observed in the tests. The data shows that super-saturation can occur when the DBP concentration is as much as 50 percent above the solubility limit. However, super-saturation cannot be relied on for maintaining nuclear criticality safety. The analytical method for determining DBP concentration in U solutions was improved so that analyses for a solution are accurate to within 10 percent. However, the overall uncertainty of results for periodic samples of the existing ...
Date: June 1998
Creator: Thompson, M. C.; Pierce, R. A. & Ray, R. J.
Partner: UNT Libraries Government Documents Department

Demonstration of a PC 25 Fuel Cell in Russia

Description: This project involved the installation of a 200kW PC25C{trademark} phosphoric-acid fuel cell power plant at Orgenergogaz, a Gazprom industrial site in Russia. In April 1997, a PC25C{trademark} was sold by ONSI Corporation to Orgenergogaz, a subsidiary of the Russian company ''Gazprom''. Due to instabilities in the Russian financial markets, at that time, the unit was never installed and started by Orgenergogaz. In October of 2001 International Fuel Cells (IFC), now known as UTC Fuel Cells (UTCFC), received a financial assistance award from the United States Department of Energy (DOE) entitled ''Demonstration of PC 25 Fuel Cell in Russia''. Three major tasks were part of this award: the inspection of the proposed site and system, start-up assistance, and installation and operation of the powerplant.
Date: September 1, 2004
Creator: Trocciola, John C.; Pompa, Thomas N. & Boyd, Linda S.
Partner: UNT Libraries Government Documents Department

The Partitioning of Acetic, Formic, and Phosphoric Acids Between Liquid Water and Steam

Description: The chemical carryover of impurities and treatment chemicals from the boiler to the steam phase, and ultimately to the low-pressure turbine and condenser, can be quantified based on laboratory experiments preformed over ranges of temperature, pH, and composition. The two major assumptions are that thermodynamic equilibrium is maintained and no deposition, adsorption or decomposition occurs. The most recent results on acetic, formic and phosphoric acids are presented with consideration of the effects of hydrolysis and dimerization reactions. Complications arising from thermal decomposition of the organic acids are discussed. The partitioning constants for these acids and other solutes measured in this program have been incorporated into a simple thermodynamic computer code that calculates the effect of chemical and mechanical carryover on the composition of the condensate formed to varying extents in the water/steam cycle.
Date: June 22, 1999
Creator: Gruszkiewicz, M. S.; Marshall, S. L.; Palmer, D. A. & Simonson, J. M.
Partner: UNT Libraries Government Documents Department

X-ray reflectivity study of formation of multilayer porous anodic oxides of silicon.

Description: The paper reports data on the kinetics of anodic oxide films growth on silicon in aqueous solutions of phosphoric acids as well as a study of the morphology of the oxides grown in a special regime of the oscillating anodic potential. X-ray reflectivity measurements were performed on the samples of anodic oxides using an intense synchrotron radiation source. They have a multilayer structure as revealed by theoretical fitting of the reflectivity data. The oscillations of the anodic potential are explained in terms of synchronized oxidation/dissolution reactions at the silicon surface and accumulation of mechanic stress in the oxide film.
Date: July 21, 1999
Creator: Chu, Y.; Fenollosa, R.; Parkhutik, V. & You, H.
Partner: UNT Libraries Government Documents Department

Advanced water-cooled phosphoric acid fuel cell development

Description: The final task of the program addressed the testing of the three short stacks described above. The overall objective of this series of short stack tests was to verify the operation of the advanced cell design at both on-site and electric utility operating conditions. The small area development stack was operated first at atmosphenc pressure (to compare its characteristics to previous atmospheric tests) and then at 120 psia to examine its ability to operate at electric utility conditions. The 10-ft{sup 2} stack was also run at pressurized conditions to verify the scaling characteristics of the features developed in this program . The small area development stack was assembled and successfully tested for 3050 hours. The first 2380 hours of testing was conducted at atmospheric pressure, and the final 670 hours was at 120 psia pressurized conditions. As shown in Figure 1, performance was stable throughout testing. Intermediate and post test inspections of the stack showed parts to be in generally good condition with no anomalies.
Date: September 1, 1992
Creator: Scheffler, G. W. & Kemp, F. S.
Partner: UNT Libraries Government Documents Department

The Cleaning of OAB Universal Covers - An Origin of Smut in Aluminum Alloys

Description: The smut that appeared on the universal covers after the OAB cleaning process consists of sub-micron size aluminum particles originating from the machining of these parts prior to cleaning. The rigorous gross and precision cleanings with Brulin in the OAB cleaning process could not completely wash these fine particles away from the surfaces. However, applying a phosphoric acid etch before the cleaning helped to remove these fine aluminum particles. Experimental results again showed that an acid etching before cleaning is essential in preventing the occurrence of smut in aluminum alloy after gross/precision cleaning. A mechanism, based on the electrostatic {zeta}-potential, is proposed to explain the occurrence of smut that is often encountered during the cleaning of aluminum alloys.
Date: May 14, 2002
Creator: Shen, T
Partner: UNT Libraries Government Documents Department

An Overview of Stationary Fuel Cell Technology

Description: Technology developments occurring in the past few years have resulted in the initial commercialization of phosphoric acid (PA) fuel cells. Ongoing research and development (R and D) promises further improvement in PA fuel cell technology, as well as the development of proton exchange membrane (PEM), molten carbonate (MC), and solid oxide (SO) fuel cell technologies. In the long run, this collection of fuel cell options will be able to serve a wide range of electric power and cogeneration applications. A fuel cell converts the chemical energy of a fuel into electrical energy without the use of a thermal cycle or rotating equipment. In contrast, most electrical generating devices (e.g., steam and gas turbine cycles, reciprocating engines) first convert chemical energy into thermal energy and then mechanical energy before finally generating electricity. Like a battery, a fuel cell is an electrochemical device, but there are important differences. Batteries store chemical energy and convert it into electrical energy on demand, until the chemical energy has been depleted. Depleted secondary batteries may be recharged by applying an external power source, while depleted primary batteries must be replaced. Fuel cells, on the other hand, will operate continuously, as long as they are externally supplied with a fuel and an oxidant.
Date: March 23, 1999
Creator: Brown, DR & Jones, R
Partner: UNT Libraries Government Documents Department

CLIMATE CHANGE FUEL CELL PROGRAM

Description: ChevronTexaco has successfully operated a 200 kW PC25C phosphoric acid fuel cell power plant at the corporate data center in San Ramon, California for the past two years and seven months following installation in December 2001. This site was chosen based on the ability to utilize the combined heat (hot water) and power generation capability of this modular fuel cell power plant in an office park setting . In addition, this project also represents one of the first commercial applications of a stationary fuel cell for a mission critical data center to assess power reliability benefits. This fuel cell power plant system has demonstrated outstanding reliability and performance relative to other comparably sized cogeneration systems.
Date: September 16, 2004
Creator: Walneuski, Mike
Partner: UNT Libraries Government Documents Department

PREMIUM ENERGY FOR LACTEC INSTITUTE FOR TECHNOLOGY DEVELOPMENT LACTEC R&D DPT. CURITIBA, STATE OF PARANA. BRAZIL

Description: On April 2002 a 200KW Phosphoric Acid Fuel Cell (PAFC) Power Plant. was installed at LACTEC Institute For Technology Development, Research and Development facilities. The power plant installed at LACTEC site is the second of its kind in the Southern Hemisphere. Its presence, not only contributed to the creation of a Fuel Cell Stationary Power market for Brazil and the rest of the region, but increased the knowledge about fuel cell technology, and marked the point of entry as a reference for the education of a new generation of applied scientists. On its first year the power plant has operated 8,558 hours achieving an availability factor of 97% and supplying 730.50MWh of premium energy. As a second regional experience with fuel cell technology, we expect this report about LACTEC PACFC power plant performance, applications and cost-benefit evaluation will provide relevant information for future regional investments on this technology.
Date: December 31, 2003
Creator: Vedovatto, Silvio
Partner: UNT Libraries Government Documents Department