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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on P(HO)3 by Materials Project

H3PO3 crystallizes in the monoclinic P2_1 space group. The structure is one-dimensional and consists of four phosphorous acid molecules and two H3PO3 ribbons oriented in the (0, 1, 0) direction. In each H3PO3 ribbon, P5+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.61 Å) and two longer (1.64 Å) P–O bond length. There are three inequivalent H+0.33+ sites. In the first H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H+0.33+ site, H+0.33+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.70 Å) H–O bond length. In the third H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.01 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one P5+ and two H+0.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na4AsP(H15O11)2 by Materials Project

Na4AsH29O18HPO4 crystallizes in the monoclinic Pc space group. The structure is one-dimensional and consists of two phosphoric acid molecules and two Na4AsH29O18 ribbons oriented in the (0, 1, 0) direction. In each Na4AsH29O18 ribbon, there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form a mixture of edge and face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.38–2.47 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form a mixture of edge and face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.39–2.46 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form a mixture of edge and face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.34–2.48 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form a mixture of edge and face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.34–2.48 Å. As5+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.71 Å) and one longer (1.78 Å) As–O bond length. There are twenty-nine inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the ninth H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.60 Å) H–O bond length. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the twenty-first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the twenty-second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the twenty-third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the twenty-fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the twenty-fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the twenty-sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the twenty-seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the twenty-eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the twenty-ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one As5+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and three H1+ atoms. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one As5+ atom. In the ninth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the tenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the eleventh O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the twelfth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the thirteenth O2- site, O2- is bonded in a single-bond geometry to one As5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to one As5+ and one H1+ atom. In the seventeenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlP3(NO6)2 by Materials Project

TlP2(NO4)2PO4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional and consists of four phosphoric acid molecules and one TlP2(NO4)2 framework. In the TlP2(NO4)2 framework, Tl1+ is bonded to eight O2- atoms to form distorted TlO8 hexagonal bipyramids that share corners with four equivalent PO4 tetrahedra and edges with two equivalent PO4 tetrahedra. There are four shorter (2.99 Å) and four longer (3.02 Å) Tl–O bond lengths. P5+ is bonded to four O2- atoms to form distorted PO4 tetrahedra that share corners with two equivalent TlO8 hexagonal bipyramids and an edgeedge with one TlO8 hexagonal bipyramid. There is two shorter (1.47 Å) and two longer (1.82 Å) P–O bond length. N4+ is bonded in a water-like geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.31 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Tl1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to one Tl1+, one P5+, and one N4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PH24W12C6N3O40 by Materials Project

(WO3)12((CH3)2NH2)3PO4 crystallizes in the trigonal R-3m space group. The structure is zero-dimensional and consists of eighteen dimethylazanium molecules, six phosphoric acid molecules, and six WO3 clusters. In each WO3 cluster, there are three inequivalent W sites. In the first W site, W is bonded in a 5-coordinate geometry to five O atoms. There is one shorter (1.73 Å) and four longer (1.95 Å) W–O bond length. In the second W site, W is bonded in a 5-coordinate geometry to five O atoms. There are a spread of W–O bond distances ranging from 1.74–1.95 Å. In the third W site, W is bonded in a 5-coordinate geometry to five O atoms. There are a spread of W–O bond distances ranging from 1.74–1.95 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two equivalent W atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms. In the third O site, O is bonded in a bent 120 degrees geometry to two equivalent W atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two W atoms. In the fifth O site, O is bonded in a single-bond geometry to one W atom. In the sixth O site, O is bonded in a single-bond geometry to one W atom. In the seventh O site, O is bonded in a bent 120 degrees geometry to two W atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms. In the ninth O site, O is bonded in a single-bond geometry to one W atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrPO10 by Materials Project

CrO6CrO4(PO4)2O2 is Silicon tetrafluoride-derived structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four cq4 molecules, four oxygen molecules, eight phosphoric acid molecules, and four CrO6 clusters. In each CrO6 cluster, Cr is bonded in an octahedral geometry to six O atoms. There is four shorter (1.81 Å) and two longer (1.83 Å) Cr–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Cr atom. In the second O site, O is bonded in a single-bond geometry to one Cr atom. In the third O site, O is bonded in a single-bond geometry to one Cr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2017

The ultimate mineral processing challenge: Recovery of rare earths, phosphorus and uranium from Florida phosphatic clay

We report phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and fine in size, with more than 50 percent having particle size smaller than 2 μm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Finally, selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Rare earths recovery and gypsum upgrade from Florida phosphogypsum

Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P 2 O 5 ), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C, REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P 2 O 5 , U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 μm, was separated from leached phosphogypsum through elutriation, in which the P 2 O 5 , U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.

58 GEOSCIENCES↗
DOE OSTI2014

Technical Analysis of Installed Micro-Combined Heat and Power Fuel-Cell System

Combined heat and power fuel cell systems (CHP-FCSs) provide consistent electrical power and hot water with greater efficiency and lower emissions than alternative sources. These systems can be used either as baseload, grid-connected, or as off-the-grid power sources. This report presents a technical analysis of 5 kWe CHP-FCSs installed in different locations in the U.S. At some sites as many as five 5 kWe system is used to provide up to 25kWe of power. Systems in this power range are considered “micro”-CHP-FCS. To better assess performance of micro-CHP-FCS and understand their benefits, the U.S. Department of Energy worked with ClearEdge Power to install fifteen 5-kWe PBI high temperature PEM fuel cells (CE5 models) in the commercial markets of California and Oregon. Pacific Northwest National Laboratory evaluated these systems in terms of their economics, operations, and technical performance. These units were monitored from September 2011 until June 2013. During this time, about 190,000 hours of data were collected and more than 17 billion data points were analyzed. Beginning in July 2013, ten of these systems were gradually replaced with ungraded systems (M5 models) containing phosphoric acid fuel cell technology. The new units were monitored until June 2014 until they went offline because ClearEdge was bought by Doosan at the time and the new manufacturer did not continue to support data collection and maintenance of these units. During these two phases, data was collected at once per second and data analysis techniques were applied to understand behavior of these systems. The results of this analysis indicate that systems installed in the second phase of this demonstration performed much better in terms of availability, consistency in generation, and reliability. The average net electrical power output increased from 4.1 to 4.9 kWe, net heat recovery from 4.7 to 5.4 kWth, and system availability improved from 94% to 95%. The average net system electric efficiency, average net heat recovery efficiency, and overall net efficiency of the system increased respectively from 33% to 36%, from 38% to 41%, and from 71% to 76%. The temperature of water sent to sit however reduced by about 16% from 51⁰C to 43 ⁰C. This was a control strategy and the temperature can be controlled depending on building heat demands. More importantly, the number of shutdowns and maintenance events required to keep the systems running at the manufacturer’s rated performance specifications were substantially reduced by about 76% (for 8 to 10 units running over a one-year period). From July 2012 to June 2013, there were eight CE5 units in operation and a total of 134 scheduled and unscheduled shutdowns took place. From July 2013 to June 2014, between two to ten units were in operation and only 32 shutdowns were reported (all unscheduled). In summary, the number of shutdowns reduced from 10 shutdowns per month on average for eight CE5units to an average of 2.7 shutdowns per month for M5 units (between two to ten units).

combined heat and power↗
DOE OSTI2016

Novel Hydrocarbon Ionomers for Durable Proton Exchange Membranes

Proton exchange membrane fuel cells (PEMFCs) are considered efficient, environmentally friendly power sources. However, there are no commercially available hydrocarbon-based proton exchange membrane (PEM) capable of achieving the DOE’s 2020 technical targets, some of which include 0.02 Ω.cm 2 area specific proton resistance at maximum operating temperature and water partial pressures from 40-80kPa, durability of 20,000 cycles (Mechanical), >500Hours (Chemical), and 20,000 cycles without 20% loss in OCV (Chemical and Mechanical), maximum operating temperature of 120°C, and $20/m 2 (at 500,000 systems/year). While significant progress has been made over the previous two decades in the development of polymer electrolytes for fuel cells, their widespread commercialization has been largely hindered by the high-cost and low-durability. NanoSonic has developed novel, cost-effective, quaternary ammonium- functionalized hydrocarbon ionomers doped with phosphoric acid as intermediate temperature (120°C) PEMs for fuel cells as energy efficient transportation alternative to internal combustion engines. These next-generation polymer membranes possess excellent film forming and mechanical properties, exceptional hydrated dimensional stability, have good proton conductivity at low relative humidity (RH) and exhibit superb stability over current state of the art perfluorosulfonic acid (PFSA) ionomers used under the harsh operating conditions of PEM fuel cells. NanoSonic’s engineered and manufactured a library of membrane types, identified a subset of best performers, and are evaluating these materials in partnership with Los Alamos National Laboratory. Membrane electrode assembly (MEA) fabrication was successfully demonstrated in during Phase I. Initial results utilizing these novel polymer membranes and non-optimize MEAs generated during this project demonstrate good proton conductivity at 80-200°C at zero humidification (RH=0%) and have notably low high frequency resistance (HFR). NanoSonic’s membranes show superior acid retention in comparison to the reference doped PBI membranes, an attribute credited to the formation of stable ionic acid pairs, in addition to polar nteractions with the polymer backbone.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2014

Rare earths solvent extraction

Separation of rare earth chlorides using di-(2-ethylhexyl)-phosphoric acid and mixer-settlers. To access the model referenced in the report, please visit https://www.netl.doe.gov/energy-analysis/details?id=C9752D2F-2602-4C6C-91C3-6A1E343CF501

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Electrode Ionomers for High Temperature Fuel Cells

HT-PEMFCs offer advantages over LT-PEMFCs because of their higher operating temperatures. These advantages include higher catalytic activity, higher tolerance to impurities, and easier thermal management. LANL, in collaboration with SNL, has developed phosphate-quaternary ammonium ionpair coordinated proton exchange membranes for use in HT-PEMFCs. Fuel cells made with the ion-pair membranes have the potential to be operated at temperatures above 200 °C, however there is a tendency for the phosphoric acid to evaporate from the electrodes at temperatures above 180 °C. Thus, there is a need to develop an ionomer that can conduct protons at high temperatures and which can be processed into MEAs. Such a polymer also needs to be extremely durable in order to function at low pH, low RH, high temperature conditions.

25 ENERGY STORAGE↗
DOE OSTI2020

A short tutorial on uranium electropolishing

Electropolishing of uranium metal is best performed in a simple aqueous solution of phosphoric acid. With +3 to +10 volts of bias potential applied to the uranium (anode) relative to a Pt counter electrode (cathode). As summarized in a Pourbaix stability diagram, these conditions yield dissolution of the U surface as UOX containing solution species without the possibility of injecting hydrogen into the metal surface. However, if the uranium is biased to negative potentials relative to the counter electrode then water may be reduced at the U surface and hydrogen gas becomes available for reaction with the U metal. The stability diagram may be modified if there are other complexing species present in solution and the potential scale shifted if a different metal is use for the counter electrode. These effects can be understood in a known way as long as solution and electrochemical cell conditions are recognized.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2019

Accelerated Testing of Selected Filler Compositions

The fillers R&D program, mostly experimental, is part of a broader R&D program that includes new process modeling and performance assessment of criticality effects and the overall importance of criticality to repository performance (consequence screening). A literature research and consultation effort with experts by Hardin and Brady (2018) identified several potentially effective and workable filler materials including cements (primarily phosphate based), molten-metal alloys, and low-temperature glasses. Filler attributes were defined and the preliminary lists were compared qualitatively. Further comparative analysis will be done (e.g., cost estimates) after experimental screening has narrowed the list of alternatives. The following cement filler compositions were selected for experimental development work and accelerated testing in FY19: Aluminum phosphate cements (APCs); more specifically aluminum oxide / aluminum phosphate (Al 2 O 3 / AlPO 4 ) cements in which Al 2 O 3 serves as the filler material bound by an AlPO 4 binder formed by the reaction of Al 2 O 3 with H 3 PO 4 ; Calcium phosphate cements (CPCs); more specifically composed of pure or nearly pure hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)); Magnesium potassium phosphate cements (MKPs) composed of magnesium oxide / magnesium potassium phosphate (MgO / MgKPO 4 ) cements in which MgO serves as the filler and MgKPO 4 serves as the binder formed by the reaction of MgO with monopotassium phosphate (KH 2 PO 4 ) and tricalcium phosphate ((Ca 3 (PO 4 ) 2 ); Two additional potential cement materials were explored preliminarily as the result of: (1) continued literature investigations into other filler candidates (wollastonite-based phosphate ceramic) and (2) the experimental discovery of a well-consolidated fly ash phosphate cement during the evaluation of fly ash as a potential filler material with Al 2 O 3 in APCs. Fly ash phosphate cements, more specifically in which a fly ash material composed primarily of mullite and quartz serves as the filler and is reacted with H 3 PO 4 to form amorphous phosphate phase(s) as the binder; Wollastonite aluminum phosphate cements (WAPC), specifically wollastonite / aluminum phosphate (CaSiO 3 / AlPO 4 ) in which CaSiO 3 serves as the filler material and AlPO 4 serves as the binder formed by Al(OH) 3 or metakaolin as Al sources and H 3 PO 4 or ammonium dihydrogen phosphate (ADP) (NH 4 H 2 PO 4 ) as phosphate sources. The FY19 effort focused on the optimization of compositions and subsequent processing of these five materials to achieve dense and well-consolidated monolithic samples with relatively low porosity. Once these goals were met basic material properties screening evaluations were performed including an assessment of dissolution resistance in water at elevated temperature (200 °C) and mechanical testing including unconfined compressive strength (UCS) testing. To date, the aluminum phosphate cements (APCs) appear to show the most promise for continued development. They are easily prepared and form smooth pourable slurries that remain stable for days with relatively low viscosities of several thousand centipoise (cP). They are then set at elevated temperatures (e.g., 170 °C) under ambient (0.1 MPa) or elevated pressure (~1MPa). Overall, they demonstrate the best dissolution resistance in water at elevated temperature (200 °C) and good compressive strengths. However, additional effort is required to optimize the APC slurry formulations and the process used for thermal curing these materials. The calcium phosphate cements (CPCs) can be formed at room temperature to produce a well-consolidated body. However, their slurry viscosities are very high (and difficult to measure) and they exhibit relatively short cure times of 2 to 3 hours. Also, dissolution resistance is very poor, the poorest of all the cements examined The same is the case for the small number of MKP cements fabricated; they cure very quickly (10 minutes or less) and disintegrate within a few hours upon immersion in distilled water. Surprisingly, fly ash reacts with phosphoric acid to form dense and well-consolidated cements but the mixture rapidly sets at room temperature (less than 30 minutes) and the subsequent conversion of the binder to an amorphous phosphate phase(s) as a function of temperature is complicated. Finally, the wollastonite aluminum phosphate cements (WAPC) are easily prepared and form smooth pourable slurries that remain stable for several hours. They are then set at 130 °C. A WAPC sample exhibited the highest compressive strengths of all the materials we evaluated but in general their dissolution resistance to water is poor.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Research tool development for catalyst, catalyst/ionomer, and ionomer characterization above 100°C (CRADA Final Report)

There is a need to develop experimental tools that address the catalyst and ionomer interface under high-temperature proton-exchange-membrane (HT-PEM) operating conditions (dry, >100°C). These conditions mean traditional water-based measurements for membrane and ionomer properties are insufficient; new ex-situ techniques are required to address and characterize expected novel materials. In this project we develop a microelectrode cell for high temperature kinetics and gas transport properties and ex-situ ionomer thin-film characterization under these conditions. We use baseline Nafion and phosphoric-acid imbibed membranes as prototype materials for measuring the membrane/acid/ionomer systems with Pt microelectrodes and demonstrate feasibility of the tools.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Dehalogenation reactions between halide salts and phosphate compounds

Reactions between phosphoric acid [H 3 PO 4 ] or ammonium hydrogen phosphates [i.e., NH 4 H 2 PO 4 , (NH 4 ) 2 HPO 4 ] and halide salts can be used to dehalogenate (remove halides from) salt-based waste streams, where the process of removing halides yields products that have more efficient disposal pathways for repository storage. In this context, the term efficiency is defined as higher waste loadings and simplified immobilization processes with potential for recycle of certain salt components (e.g., 37 Cl as H 37 Cl or NH 4 37 Cl). The main streams identified for these processes are nuclear wastes generated during electrochemical reprocessing of used nuclear fuel as well as used halide salts from molten salt reactor operation. The potential byproducts of these reactions are fairly consistent across the range of halide species (i.e., F, Cl, Br, I) where the most common are hydrogen halides [e.g., HCl (g) ] or ammonium halides (e.g., NH 4 Cl). However, trihalide compounds (e.g., NCl 3 ), nitrogen triiodide ammine adducts [NI 3 ·(NH 3 ) x ], and ammonium triiodide (NH 4 I 3 ) are also possible. Several of these byproducts (i.e., NCl 3 , NBr 3 , NI 3 , and NH 4 I 3 ) are shock-sensitive contact explosives so their production in these processes must be tracked and carefully controlled, which includes methods of immediate neutralization upon production such as direct transport to a caustic scrubber for dissolution. Several benefits arise from utilizing H 3 PO 4 as the phosphate additive during dehalogenation reactions for making iron phosphate waste forms including more oxidized iron (higher Fe 3+ :Fe 2+ ratios), higher chemical durabilities, and the avoidance of trihalides, but the byproducts are hydrogen halides, which are corrosive and require special handling.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Microwave-assisted synthesis of transition metal phosphide

A method of synthesizing transition metal phosphide. In one embodiment, the method has the steps of preparing a transition metal lignosulfonate, mixing the transition metal lignosulfonate with phosphoric acid to form a mixture, and subjecting the mixture to a microwave radiation for a duration of time effective to obtain a transition metal phosphide.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Methods of refining natural oils and methods of producing fuel compositions

A method of refining a natural oil includes: (a) providing a feedstock that includes a natural oil; (b) reacting the feedstock in the presence of a metathesis catalyst to form a metathesized product that includes olefins and esters; (c) passivating residual metathesis catalyst with an agent selected from the group consisting of phosphorous acid, phosphinic acid, and a combination thereof; (d) separating the olefins in the metathesized product from the esters in the metathesized product; and (e) transesterifying the esters in the presence of an alcohol to form a transesterified product and/or hydrogenating the olefins to form a fully or partially saturated hydrogenated product. Methods for suppressing isomerization of olefin metathesis products produced in a metathesis reaction, and methods of producing fuel compositions are described.

02 PETROLEUM↗
DOE OSTI2019

Non-noble metal electrocatalysts for oxygen depolarized cathodes and their uses

Highly anion resistant electrocatalysts suitable for catalyzing an oxygen reduction reaction (ORR) and methods of synthesizing the same are provided. The catalysts contain a transition metal, a heteroatom, and carbon. Preferred catalysts include N as the heteroatom and Fe as the transition metal, with active sites having Fe--N.sub.4 stoichiometry (Fe.sub.xN.sub.yC.sub.z) as part of a metal organic framework (MOF) or sequestered within a MOF. Electrocatalysts further including Fe nanoparticles (Fe.sub.NPs) are also provided. The catalysts described herein are applicable in the preparation of oxygen decoupled cathodes (ODC) for chlorine evolution processes such as in chlor-alkali cells or HCl electrolyzers. The catalysts are also useful in preparing ODC for use in fuel cells, including phosphoric acid fuel cells.

Tylus, Urszula↗