Haut PDF Thermodynamic study and assessment of the fluorine-iron system

Thermodynamic study and assessment of the fluorine-iron system

Thermodynamic study and assessment of the fluorine-iron system

Thermodynamic study of iron-fluorine system Sylvie Chatain 1 , Jean-Louis Flèche 1 , Mickaël Achour 2 , Laure Martinelli 1 1 Den-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME) – CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France 2 Hall de Recherche de Pierrelatte (HRP) – Division Chimie et Enrichissement, F-26701, Pierrelatte, France

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Thermodynamic Assessment of the Fe-Te System. Part II Thermodynamic modelling

Thermodynamic Assessment of the Fe-Te System. Part II Thermodynamic modelling

Corresponding author: arvhult@kth.se Abstract A thermodynamic description of the Fe-Te system modeled via the Calphad method is proposed, based on data published in a preceding publication Part I: Experimental study, and that available in literature. End-member formation energies for the phases , , , and , as well as lattice stabilities of FCC and BCC tellurium, have been evaluated via DFT and used in the numerical optimization. The final Gibbs energy models fit thermodynamic and phase diagram data well, and inconsistencies are discussed. The thermodynamic description is then used to evaluate Gibbs energy of formation for selected Fe-Te compounds of interest for the modeling of internal corrosion of stainless steel fuel pin cladding during operation of Liquid Metal-cooled Fast Reactors (LMFR).
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Thermodynamic study of the in-vessel corium - Application to the corium/concrete interaction

Thermodynamic study of the in-vessel corium - Application to the corium/concrete interaction

- 21 - a) b) Figure 9: Possible in-vessel corium configuration in the case of an in-vessel relocation strategy. a) oxidic melt underneath the metallic melt; b) heavy metal melt formation under the oxidic pool [15] Since liquid metal has a low emissivity, the radiative heat transfer from the metal is limited. The main part of the heat release occurs at the molten metallic layer/steel vessel interface. If the thickness of the upper metallic layer is excessively reduced, the so-called focusing effect may take place. In this situation, the heat flux from the liquid metal to the steel vessel is important and it may lead to the vessel breach (if this heat flux is greater than the Critical Heat Flux, CHF=1.5 MWm -2 in the reported scenario). Seiler et al. considered the U-Zr-Fe-O system as a first approximation in-vessel corium. The authors showed that depending on the amount of dissolved iron an inversion of the melts density may be observed (Figure 10). The intersection between the oxidic phase density and the metallic phase density in Figure 10 gives the maximum amount of steel (iron simulates steel behaviour) that stratify under the oxidic pool. For example, for an in-vessel corium with 30 % of oxidised zirconium (C30 in Figure 10), the metallic phase is heavier than the oxidic phase until 25 tons of dissolved iron. This means that a considerable amount of steel may stratify under the oxidic pool. It may be also noted that the density of the oxidic phase is practically not affected by the iron addition suggesting that the solubility of iron in the oxidic phase is limited.
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Thermodynamic assessment of the aluminum corner of the Al-Fe-Mn-Si system

Thermodynamic assessment of the aluminum corner of the Al-Fe-Mn-Si system

the section at 14 wt pct Si, as indicated by the dotted line in Figure 4 (b). While Balitchev et al. [ 20 ] did not show their calculations for that silicon content, Abou and Malakhov’s [ 22 ] results were similar to those found in the current study, i.e., precipitation of Si at temperatures close to 600 C at 14 wt pct Si. Accordingly, the dotted line in Figure 4 (b) remains unexplained, even by assess- ments based on these experimental results. Along with the conclusions of the review presented in Section I, this shows the need for further experiments before rejecting the view proposed long ago and adopted in the present work that no quaternary phase appears in the Al-rich corner of the Al-Fe-Mn-Si phase diagram and that the alpha-AlMnSi and beta-AlMnSi phases extend signifi- cantly from the Al-Mn-Si system within the quaternary. The present optimization was finally used to calculate the section of the liquidus projection of the Al corner of the quaternary Al-Fe-Mn-Si system at 0.3 wt pct Mn for comparison with the experimental section proposed by Munson. [ 6 ] The few data points used by these authors were located along the boundary between the alpha- AlMnSi and the alpha-s 5 phases, while all other bound-
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Experimental investigation and thermodynamic modeling of molybdenum and vanadium-containing carbide hardened iron-based alloys

Experimental investigation and thermodynamic modeling of molybdenum and vanadium-containing carbide hardened iron-based alloys

A technique for the microstructural study of steels, based on the use of matrix dissolution to collect the very low number density precipitates formed in martensitic steels, has been considerably improved. This technique was applied to two different grades of alloy, characterized by high nickel and cobalt contents and varying chromium, molybdenum and vanadium contents. The technique was implemented at tem- peratures ranging between 900 !C and 1000 !C, in order to accurately determine experimental data including the crystallographic structure and chemical composition of the carbides, the carbide solvus temperatures, and variations in the chemical composition of the matrix. These experimental investiga- tions reveal that the solubility of molybdenum in FCC carbides can be very high. These results have been compared with the behavior predicted by computational thermodynamics, and used to evaluate and improve the thermodynamic Matcalc steel database. This upgraded database has been validated on three other steels with different chemical compositions, characterized by the same Fe–Cr–Mo–V–C system.
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The Zr–Sn binary system: New experimental results and thermodynamic assessment

The Zr–Sn binary system: New experimental results and thermodynamic assessment

c = 9 . 927 in the two phase domain η + ZrSn 2 . The two alloys in the two phase domains were selected to study the η phase at its richest and poorest Zr compositions. To study the A 15 phase, an alloy with 20 at.% Sn was synthesized. In none of the samples, weight losses exceeded ∼ 1%. The annealing was performed under argon in a silica tube. In order to avoid any reaction with the silica the alloys were protected with Ta foils. The sample with the nominal composition 20 at.% Sn was annealed for 240 h at 1273 K. The samples, which contained 34, 41 and 49 at.% Sn, were annealed for 216 h at 1273 K. After the annealing treatment the alloys were quenched in water at room temperature. The sample containing 40 at.% Sn was annealed for 6 h at 1883 K in an induction furnace in a cold copper crucible under argon atmosphere and quenched by turning off the induction power. This annealing treatment was performed in order to check the closure of the miscibility gap. DSC experiments were performed on a sample with 10 at.% Sn previously thermally treated at 1073 K during 680 h.
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A comprehensive thermodynamic study of the U-Am-O ternary system: multiple experimental investigations and Calphad modelling

A comprehensive thermodynamic study of the U-Am-O ternary system: multiple experimental investigations and Calphad modelling

to foresee the O/M of these compounds under different conditions. Thanks to the new experimental data acquired on the U-Am-O system, a CALPHAD assessment will be performed and the resulting model will be integrated in the Thermodynamic of Advanced Fuel International Database (TAFID). References

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Thermodynamic Assessment of the CaO–Al2O3–SiO2 System

Thermodynamic Assessment of the CaO–Al2O3–SiO2 System

was now examined how well the site fraction y O 2 follows a CaO in the CaO–Al 2 O 3 –SiO 2 system. Lines for a series of those two quantities were thus calculated from the present model, and have been plotted in Figs. 16 and 17. There is an encouraging similarity, and it may be interesting to continue this study by examining which of these two actually describes the purification power of the slag best.

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Thermodynamic study of iron-fluorine system

Thermodynamic study of iron-fluorine system

Thermodynamic study of iron-fluorine system Sylvie Chatain 1 , Mickaël Achour 2 , Jean-Louis Flèche 1 , Laure Martinelli 1 1 Den-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME) – CEA, Université Paris-Saclay, F-91919, Gif-sur-Yvette, France 2 Hall de Recherche de Pierrelatte (HRP) – Division Chimie et Enrichissement, F-26701, Pierrelatte, France

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Comprehensive Thermodynamic Study of the Calcium Sulfate–Water Vapor System. Part 1: Experimental Measurements and Phase Equilibria

Comprehensive Thermodynamic Study of the Calcium Sulfate–Water Vapor System. Part 1: Experimental Measurements and Phase Equilibria

the temperature was reduced, and the carrier gas was inserted with controlled humidity. In this middle part of the experiment, P D E F was kept constant, and increasing T plateaus were performed throughout the experiment. The @T, P D E F G conditions were maintained until stabilization of the mass signal. We observe an almost instantaneous 8% mass uptake with the insertion of humid gas (the mass of the sample increases from 4.20 mg to 4.54 mg). Afterward, we observe that for each increasing T step, the sample loses mass and m d reaches a new equilibrium value. This systematic behavior can be observed in the areas identified as zones 1 and 2, better shown in Figure 3(b) and Figure 3(c), respectively. According to @T, P D E F G, the overall mass m d of the sample can increase or decrease by hydration or dehydration processes. This behavior can be identified as bivariant, as the equilibrium values of m d depend on both intensive parameters of the system, T and P D E F (two degrees of freedom).
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Fluorine in the Earth and the solar system, where does it come from and can it be found?

Fluorine in the Earth and the solar system, where does it come from and can it be found?

Table 6 ). Fluorine studies in Earth Science are far from complete. As concluding remarks, we summarize four challenges discussed above. (1) Behavior of F in hydrosphere: data on F abundance in various surface waters, especially other than ocean, are required for understanding the F transfer be- tween hydrosphere and crustal rocks during erosion and weathering. In addition, the role of biology in surface F cycle needs to be assessed quantitatively. (2) F abundance in metamorphic rocks: amount of F present in various types of metamorphic rocks is not studied extensively so far. Because of this, geochemical transport of F during the metamorphism is yet to be understood, except for certain cases related to a prograde metamorphism during the subduction of an oceanic lithosphere [22c] . (3) F abundance in mantle peridotites: data on F abundances in peridotites are also scarce. This prevents an assessment of F abundance in the mantle from the peridotite data. Fluorine is also expected to provide an additional geochemical vector characterizing the metasomatic process in the mantle beneath continents, for example, providing insights into the origin of kimberlite (a diamond-bearing magma). (4) F incorporation in metallic core: although F is not expected to incorporate into the metallic more in a large quantity, even a small quantity can in fluence the terrestrial budget signi ficantly. Furthermore, at the extreme high pressure and temperature, new F-bearing minerals can be formed. Investigation of chemical reaction at the extreme condi- tions therefore potentially brings in new discoveries regarding F behavior deep inside the Earth.
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Thermodynamic Assessment of the Fe-Te System. Part I: Experimental study

Thermodynamic Assessment of the Fe-Te System. Part I: Experimental study

boundaries of two-phase samples evaluated from the composition analyses via EDS and WDS. The respective tie-lines are shown in Figure 2, imposed on the calculated phase diagram compared with published phase boundary data (see Part II: Thermodynamic modelling). Filled symbols represent the prepared average sample compositions (Table 2), and empty symbols represent the evaluated phase boundary compositions (Table 3). The tie-lines are overall consistent with available solubility data. Most heat treated samples showed no to small interaction with the silica ampoule. Samples treated in equilibrium with liquid showed a thin, soot-like, dark layer on the inner wall of the ampoule; while a reaction had clearly taken place, the extent was deemed small enough to not affect the state of the bulk sample and the ampoules remained intact. The largest extent of reaction was seen in sample FT58_S2, being cratered with large semi-spherical bubbles. The outer rim of the sample showed a clear and uniform, about 5 µm thick, region of phase composition. Analysis of the deposits on the ampoule revealed tellurium oxide particles. In all two-phase samples, oxygen was concentrated in the most Fe-rich phase, i.e. the phase with more vacant interstitial sites.
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Assessment of the Al–Fe–Ti system

Assessment of the Al–Fe–Ti system

Databases for CALPHAD-type calculations have been made available for each of the corners of the Al–Fe–Ti system. The concerted European COST action 507 has led to the development of a database for aluminium alloys [117] for which assessments were however limited to the description of binary and some ternary systems, but not the Al–Fe–Ti one. In fact, no CALPHAD-type description of the whole ternary Al–Fe–Ti system is available at present. As a matter of fact, the only tentative CALPHAD-type assessment of the Al–Fe–Ti system is due to Dew-Hughes and Kaufman [118] who calculated the 1000 °C isotherm. The extension of both the Laves phase and the B2-ordered phase FeTi in the ternary system was unexpected for these authors, who assumed that Al should have substituted Ti in both phases, and this led them to perform new experiments which just confirmed previous data. Their conclusion, which appears still valid, is that further theoretical studies should attack the problem.
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PHYSICO-CHEMICAL CHARACTERISTICS AND QUALITY OF FEED WATERS OF THE EL-OUED CITY STUDY OF CASE (FLUORINE AND ARSENIC)

PHYSICO-CHEMICAL CHARACTERISTICS AND QUALITY OF FEED WATERS OF THE EL-OUED CITY STUDY OF CASE (FLUORINE AND ARSENIC)

Dans ce stade on cherche sue la méthode plus approprier pour les caractéristiques physico-chimiques des eaux d'alimentation et la méthode moins couteux. 8. RÉFÉRENCES [1] Amini M., Abbaspour K.C., Berg M., Winkel L., Hug S.J., Hoehn E., Yang H., Johnson C.A. Statistical modeling of global geogenic. arsenic contamination in groundwater. Environmental Science and Technology. 2008, 42, 3669 –3675.

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Fluorine

Fluorine

lower continental crust, by a factor of 1.4 - 2.3 (Rudnick and Gao 2004). Fluorine contents in magmatic rocks are in the 100s to 1000s of ppm range. Highly fractionated peraluminous and peralkaline granitoids, and some basaltic rocks, show the highest abundances, as F is generally concentrated into magmas during crystal fractionation. In addition, F is incorporated into silicate melt by bonding to Si and Al, resulting its higher solubility in felsic than mafic melts (Dalou et al. 2015).

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Study of Uranium Peroxide Precipitation Thermodynamic and Kinetic approaches

Study of Uranium Peroxide Precipitation Thermodynamic and Kinetic approaches

+ + 4 ↔ ∙ 4 + Solid particles must fulfill specific requirements, in particular concerning the size. Thus, the control of the crystal growth becomes a key parameter during the uranium peroxide precipitation. Moreover, the solubility product, K s , is required to calculate the driving force on which the kinetic law depends. For the uranium peroxide precipitation, the supersaturation ratio, , is linked to the activities of the uranyl and peroxide ion as:

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Thermodynamic assessment of platinoid and molybdate phases in nuclear waste glasses

Thermodynamic assessment of platinoid and molybdate phases in nuclear waste glasses

No data The modeling of CaO-MoO 3 , Na 2 O-MoO 3 , Na 2 MoO 4 -CaMoO 4 and of SiO 2 - Na 2 O-MoO 3 systems has been carried out. This study makes it possible to predict the formation of the molybdate phases in the simplified glass melt. The next step will focus on the introduction of B 2 O 3 in the database to get closer to the real industrial glass composition.

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Thermodynamic modelling of the Fe-Sn-Zr system based on new experiments and first- principles calculations

Thermodynamic modelling of the Fe-Sn-Zr system based on new experiments and first- principles calculations

Borrelly et al.[45] determined the solubility in the different solid solutions. The phase diagram was reviewed in the whole composition range by Alekseeva et al. [46]. Later, Bhanumurthy et al. [47,48] and Kumar et al. [49] reported the C16 phase to be a high temperature stable phase. Servant et al. [3] reinvestigated the invariant reaction temperatures as well as the melting temperature of the C15 phase. A detailed review and a very careful reinvestigation of the whole composition range of this system has been carried out by Stein et al. [14] using metallography, XRD, EPMA and DTA measurements. These authors have shown that the presumed Fe 23 Zr 6 compound stable at high temperature is actually an
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EOS ® orthopaedic imaging system to study patellofemoral kinematics : Assessment of uncertainty

EOS ® orthopaedic imaging system to study patellofemoral kinematics : Assessment of uncertainty

In addition, during the knee’s flexion—extension, there is automatic rotation of the tibia, which authors have agreed has a real influence on the patellar tracking [16] , even if this influence has not been accurately described [10] . This assessment problem may be related to the probable existence of several instantaneous rotation axes during the flexion—extension cycle [29] . The studies that controlled for this rotation [27] show great variability in this aspect of patellofemoral kinematics, which is why a certain number of authors leave the rotation free. We opted for this second solution in our study with a method that allowed us to apply return strength to the tibia at the same time.
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Study of the behavior of iron ore particles in spiral concentrators

Study of the behavior of iron ore particles in spiral concentrators

The tests conducted on a single spiral followed a factorial design using wash water addition, feed rate and slurry solids concentration as the experimental factors. For the test conditions the wash water addition was found to have the most significant effect on the spiral performance. Increasing the wash water flow rate enhances the concentrate grade but reduces the iron recovery. The major effect of wash water was found to be on coarse particles. Other experimental factors (feed rate and slurry solids concentration of the feed) did not show any significant effect on recovery and concentrate grade. This result is most likely due to the high amplitude of wash water variation applied for the tests compared to that of other factors. The application of a stepwise regression confirms the significant effect of the wash water addition on the iron recovery and concentrate grade. Subsequent testing for these variables should use lower amplitude of wash water variation in order to be able to identify the effect of slurry solids concentration and feed rate on the spirals performance. In summer 2014 tests were conducted on a test rig consisting of three parallel spirals with 3, 5 and 7 turns at COREM. The test rig is well conceived and operates in a closed circuit with a recirculation of wash water addition, which is automatically controlled. A sampling system allows simultaneous sampling from 24 streams to minimize the disturbance to the process. The main objective of the test work on the test rig is to provide an answer to the initially felt obvious question of: ‘What is the effect of the number of turns on spirals performance?’ Answering this question will help plant operators to decide whether they should invest in 5-turn or 7-turn-spirals, or even a 3-turn-spiral could be sufficient for their needs. The parallel spirals are operated at identical operating conditions, e.g. feed characteristics (flow rate, slurry solids concentration and composition). Although more than 10 tests were conducted on the spiral test rig, we have not been able to clearly identify the role of the number of turns on spirals operation. In most of the tests the 3-turn-spiral outperforms, in terms of recovery, the 5 and 7-turn-spirals. There is no explanation to this counter intuitive behavior of the spirals and at the time of writing these lines the personnel of COREM is still investigating the process to identify the origin of this behavior (M. Renaud, March 2015, personnel communication).
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