Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements (original) (raw)
Related papers
1989
A requirement for modelling the chemical behavior of groundwater in a nuclear waste repository is accurate thennodynamic data pertaining to the participating minerals and aqueous species. In particular, it is important that the thennodynamic properties of the aluminate ion be accurately determined, because most rock fonning minerals in the earth's crust are aluminosilicates, and most groundwaters are neutral to slightly alkaline, where the aluminate ion is the predominant aluminum species in solution. Without a precise knowledge of the thennodynamic properties of the aluminate ion, aluminosilicate mineral solubilities cannot be determined. The thennochemical properties C;,298, S298 and MIf,298 and LlGf298of the aluminate ion have been determined from the solubilities of the aluminum hydroxides and oxyhydroxides in alkaline solutions between 20 and 350°C. An internally consistent set of thermodynamic properties, C; , S298, LlHf~98 and LlGf~98 have been determined for gibbsite, boehmite, diaspore and corundum. The thermodynamic properties of bayerite have been provisionally estimated and a preliminary value for~Gf.298of nordstrandite has been determined. 5. COMPARISON OF THE THERMODYNAJ.\tIIC PROPERTIES OF GIBBSITE, BOEHMITE AND DIASPORE 32 5.1 Rcconciliation of log~for the Reaction Gibbsite =Boehmite + Water, Based on Solubility Measurements with that Based on Calorimetric Measurements 32 5.2 Calculation of log K?(T)(boehmite), dHf~98(boehmite)and S298(boehmite) 40 6. CALCULA nON OF THE THERMODYNAMIC PROPERTIES OF THE ALUMINATE ION, AI(OH)4",AND LOG~4(T)(GIBBSlTE, BOEHMITE, DIASPORE) 47 6.1 Derivation of log Kt (T) and D.G?(T) from Solubility Measurements 47 6.1.1 Regression of log~4, (T)(boehmite) and Determination of LogKs4,(T)(gibbsite) and Log~4, m(diaspore) 47 6.1.2 Calculation of logKr~T{Al(OH)i) 50 vii 6.2 Calculationof C; , S298 and~Ht298 51 6.3 Comparison of~Gf (T)(Al(OH)i), Predicted by the HKF Equation of State, with that Determined from Solubility Measurements. 52 7.
2013
calorimetric measurements 3 4 Hélène Gailhanou, Philippe Blanc, Jacques Rogez, Georges Mikaelian, Katsuya 5 Horiuchi, Yasuhisa Yamamura, Kazuya Saito, Hitoshi Kawaji, Fabienne Warmont, Jean6 Marc Grenèche, Philippe Vieillard, Claire I. Fialips, Eric Giffaut and Eric C. Gaucher 7 8 BRGM, 3 Av. C. Guillemin, BP6009, F-45060 Orleans, France 9 IM2NP-CNRS Aix Marseille Université, FST Saint-Jérôme, F-13397 Marseille Cedex 20, France 10 Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 30511 8571 Japan 12 Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503 Japan 13 CRMD-CNRS, 1b Rue de la Ferollerie, F-45071 Orleans, France 14 LUNAM, Université du Maine, Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, F-72085 Le 15 Mans Cedex 9, France 16 CNRS-IC2MP-UMR-7285 Hydrasa, 5 Ave Albert Turpain, 86022 POITIERS-Cedex, France 17 Andra, F-92298 Châtenay-Malabry Cedex, France. 18 19 20 Corresponding author...
Chemical Engineering Division, thermochemical studies annual report, July 1973--June 1974
1974
Standard enthalpies of formation have been determined for the following compounds: Cs2U207(c), 8-Na2U04(c), BaU04(c), HI(aq), CsN03(c), Cs2C03(c), CsCl(c), RbCl(c), Cs2Cr04(c), and Cs2Cr207(c). Preliminary reaction calorimetric studies of WS 2 and Li-Al alloys are described. High-temperature enthalpies and other thermodynamic properties are reported for~and 8-Na2U04(c); Cs2U04(c), and Al203 (c) • SUMMARY In connection with continuing studies of the thermodynamics of chemical. reactions in nuclear reactors, t.Hf values have been obtained for Cs2U207, ~-and 8-Na2U04, and BaU04. A thermodynamic analysis indicates that Cs 2 uo 4 is likely to be the dominant species formed in oxide fuel + Cs reactions. The enthalpy of the ~to 8-Na2U0 4 transition at 298.15 K has been determined. In a variety of thermochemical cycles, t.Hi(I-,aq) is a key component. Current critical compilations assign the rather large uncertainty of ± 0.2 kcal mol-l to this value. The present study has reduced the uncertainty to± 0.02 kcal mol-1 • CsN03 Previous determinations of the enthalpy of solution and, hence, of the enthalpy of formation, of CsN03 were rather uncertain. Current studies have yielded a new precise value for t.Hf(CsNQ3). By combining solubility and enthalpy of solution data, the standard entropy, S 0 (CsN0 3), has been deduced. The thermodynamic properties of Cs 2 C03 are of interest in connection with seed loss in the coal-fired MHD process. The enthalpy of solution of Cs 2 C03 in 0.5M CsOH was measured, and the standard enthalpy of formation, t.H£(Cs2C03, c, 298.15 K), was derived.
Thermodynamic data provided through the FUNMIG project: Analyses and prospective
Applied Geochemistry, 2012
In this paper some of the needs for good quality thermodynamic data in radioactive waste management are highlighted. A presentation of the thermodynamic data produced within the 6th EC framework programme integrated project FUNMIG (Fundamental processes of radionuclide migration) and how these have helped in filling relevant thermodynamic data gaps is given. The manuscript does not intend to be a complete review of thermodynamic data, but a short overview of the aqueous complexation of Am(III), lanthanides (III), U(VI), and Th(IV) by sulfates, silicates, carbonates and phosphates. The work presented is based on the latest developments published in the literature and specifically addressed within the IP FUNMIG.
Computers & Geosciences, 1992
A~traet-Recent advances in theoretical geochemistry permit calculation of the standard molal thermodynamic properties of a wide variety of minerals, gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000°C. The SUPCRT92 software package facilitates practical application of these recent theories, equations, and data to define equilibrium constraints on geochemical processes in a wide variety of geologic systems. The SUPCRT92 package is composed of three interactive FORTRAN 77 programs, SUPCRT92, MPRONS92, and CPRONS92, and a sequential-access thermodynamic database, SPRONS92.DAT. The SUPCRT92 program reads or permits user-generation of its two input files, CON and RXN, retrieves data from the direct-access equivalent of SPRONS92.DAT, calculates the standard molal Gibbs free energy, enthalpy, entropy, heat capacity, and volume of each reaction specified on the RXN file through a range of conditions specified on the CON file, and writes the calculated reaction properties to the output TAB file and, optionally, to PLT files that facilitate their graphical depiction. Calculations can be performed along the liquid side of the H20 vaporization boundary by specifying either temperature (T) or pressure (P), and in the single-phase regions of fluid H20 by specifying either T and P, T and H20 density, T and log K, or P and log K. SPRONS92.DAT, which contains standard molal thermodynamic properties at 25°C and 1 bar, equation-of-state parameters, heat capacity coefficients, and phase transition data for approximately 500 minerals, gases, and aqueous species, can be augmented or otherwise modified using MPRONS92, and converted to its direct-access equivalent using CPRONS92.
Gibbs free energies of formation at 298 K for imogolite and gibbsite from solubility measurements
Geochimica et Cosmochimica Acta, 1994
The aqueous solubility of synthetic imogolite at 298 K and 1 bar pressure and at 373, 393, 408, and 423 K and equilibrium vapor pressure was determined in 0.01 M NaCl at two initial pH levels. Samples were run with and without pretreatment with HCl and in the presence and absence of gibbsite or boehmite. At 298 K and 1 bar pressure, dissolution of non-HCl-washed synthetic imogolite at the initial pH values of 1.8 and 2.2, with or without addition of AlC13 and H&O., , approached equilibrium within 335 and 33 days, respectively. Dissolution of HCl-washed imogolite and gibbsite at initial pH 2.5 and 3.0 reached equilibrium within 332 and 487 days, respectively. There was no difference between the log IAP values at equilibrium from non-HCl-washed and HCl-washed imogolite samples. Dissolution of non-HCI-washed synthetic imogolite and gibbsite at an initial pH 2.2 attained equilibrium within 485 days of equilibration, but equilibrium was not reached after 861 days for samples at an initial pH 1.8. Dissolution of HCl-washed imogolite at initial pH values of 2.5 and 3.0 did not reach equilibrium within 766 days. At 373 and 393 K and an initial pH 3.0, dissolution of imogolite and synthetic boehmite reached equilibrium. The calculated Gibbs free energies of formation at 298 K were 2923.79 + 3.38 (synthetic imogolite), -2920.83 + 3.92 (natural imogolite), -1155.06 +-1.43 (gibbsite), -915.10 + 1.83 (boehmite, extrapolated from elevated temperature), and -920.64 ? 1.4 1 kJ mol-' (boehmite, from 298 K solubility). The results indicate that synthetic imogolite is more soluble than earlier reports suggest and natural imogolite is less stable than its synthetic counterpart.
Computers & Geosciences, 1992
A~traet-Recent advances in theoretical geochemistry permit calculation of the standard molal thermodynamic properties of a wide variety of minerals, gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000°C. The SUPCRT92 software package facilitates practical application of these recent theories, equations, and data to define equilibrium constraints on geochemical processes in a wide variety of geologic systems. The SUPCRT92 package is composed of three interactive FORTRAN 77 programs, SUPCRT92, MPRONS92, and CPRONS92, and a sequential-access thermodynamic database, SPRONS92.DAT. The SUPCRT92 program reads or permits user-generation of its two input files, CON and RXN, retrieves data from the direct-access equivalent of SPRONS92.DAT, calculates the standard molal Gibbs free energy, enthalpy, entropy, heat capacity, and volume of each reaction specified on the RXN file through a range of conditions specified on the CON file, and writes the calculated reaction properties to the output TAB file and, optionally, to PLT files that facilitate their graphical depiction. Calculations can be performed along the liquid side of the H20 vaporization boundary by specifying either temperature (T) or pressure (P), and in the single-phase regions of fluid H20 by specifying either T and P, T and H20 density, T and log K, or P and log K. SPRONS92.DAT, which contains standard molal thermodynamic properties at 25°C and 1 bar, equation-of-state parameters, heat capacity coefficients, and phase transition data for approximately 500 minerals, gases, and aqueous species, can be augmented or otherwise modified using MPRONS92, and converted to its direct-access equivalent using CPRONS92.