Isomorphic Co-Crystallization of Ammonium and Rubidium Bromocarnallites

1994 ◽  
Vol 59 (8) ◽  
pp. 1815-1819 ◽  
Author(s):  
Christomir Christov ◽  
Christo Balarew ◽  
Stefka Tepavitcharova
Keyword(s):  
Distribution Coefficients ◽  
Mixed Crystals ◽  
Solubility Isotherm ◽  
Continuous Series ◽  
Liquid Phases

The solubility isotherm of the system NH4Br.MgBr2.6 H2O - RbBr.MgBr2.6 H2O - H2O has been investigated at 75 °C and formation of a continuous series of mixed crystals is established. The factors determining the values of the distribution coefficients of the components between the crystalline and liquid phases are discussed.

Evaluation of distribution coefficients for the prediction of strontium and cesium migration in a uniform sand

1982 ◽  
Vol 19 (1) ◽  
pp. 92-103 ◽  
Author(s):  
W. D. Reynolds ◽  
R. W. Gillham ◽  
J. A. Cherry
Keyword(s):  
Distribution Coefficient ◽  
Breakthrough Curves ◽  
Distribution Coefficients ◽  
Column Experiments ◽  
Advection Equation ◽  
Dispersion Models ◽  
Advection Dispersion ◽  
Liquid Phases ◽  
Long Tails ◽  
The Mathematical Model

The validity of using a distribution coefficient (Kd) in the mathematical prediction of strontium and cesium transport through uniform saturated sand was investigated by comparing measured breakthrough curves with curves of simulations using the advection-dispersion and the advection equations. Values for Kd were determined by batch equilibration tests and, indirectly, by fitting the mathematical model to breakthrough data from column experiments. Although the advection-dispersion equation accurately represented the breakthrough curves for two nonreactive solutes (chloride and tritium), neither it nor the advection equation provided close representations of the strontium and cesium curves. The simulated breakthrough curves for strontium and cesium were nearly symmetrical, whereas the data curves were very asymmetrical, with long tails. Column experiments with different pore-water velocities indicated that the shape of the normalized breakthrough curves was not sensitive to velocity. This suggests that the asymmetry of the measured curves was the result of nonlinear partitioning of the cations between the solid and liquid phases, rather than nonequilibrium effects. The results indicate that the distribution coefficient, when used in advection-dispersion models for prediction of the migration of strontium and cesium in field situations, can result in significant error.

Electrochemical preparation and properties of the mixed-crystalline hexavanadates MxM′4−xV6O16, M, M′ = NH4, K, Rb, Cs

1990 ◽  
Vol 68 (8) ◽  
pp. 1283-1292 ◽  
Author(s):  
E. Andrukaitis ◽  
P. W. M. Jacobs ◽  
J. W. Lorimer
Keyword(s):  
Chemical Analysis ◽  
Alkali Metal ◽  
Mixed Crystals ◽  
Continuous Series ◽  
Alkali Metal Cations ◽  
X Ray Diffraction ◽  
Ammonium Ions ◽  
Electrochemical Preparation ◽  
X Ray ◽  
End Members

Coherent deposits of oriented, crystalline MxM′4−xV6O16+δ, with M, M′ = K, Rb, Cs, or NH4, 0.0 ≤ x ≤4.0 and 0.00 ≤ δ ≤ 0.13, have been prepared electrochemically on various conducting substrates from metavanadate solutions containing ammonium or alkali metal cations, singly or in combination. Chemical analysis and X-ray diffraction show that the deposits consist of a continuous series of mixed crystals based on the isomorphic end members M4V6O16 and M′4V6O16.The deposits can be oxidized electrochemically, with removal of M and M′ atoms, and the products can be used as cathodes for insertion of lithium, with the largest capacity achieved about 1.0 mol% of total vanadium. Cycling of the electrodes improves capacity, with insertion of lithium reaching 25 mol% of total vanadium. This gain in capacity results from further removal of alkali metal or ammonium ions from the electrode during the oxidation step of the cycling process.The results extend the range of composition of homogeneous phases in the system (NH4)2O–K2O–V2O4–V2O5. Keywords: alkali metal hexavanadates, electrochemical preparation.On a préparé des dépôts cohérents qui contiennent des cristaux orientés de MxM′4−xV6O16+δ, avec M, M′ = K, Rb, Cs ou NH4, 0,0 ≤ x ≤4,0 et 0,00 ≤ δ ≤ 0,13, par la méthode de voltammétrie cyclique sur des substrats divers et dans des solutions de metavanadates qui contiennent des cations des métaux alcalins ou d'ammonium seuls ou des combinations de tels ions. L'analyse chimique et la diffraction des rayons X ont démontré que les dépôts comprennent une série continue de cristaux mixtes basée sur les membres terminaux M4V6O16 et M′4V6O16.

scholarly journals A spectro-photometric comparsion of the emissivity of solid liquid copper and of liquid silver at high temperatures with that of a full radiator

1913 ◽  
Vol 88 (602) ◽  
pp. 195-205 ◽  
Keyword(s):  
High Temperatures ◽  
Liquid Copper ◽  
Freezing Point ◽  
Mixed Crystals ◽  
Continuous Series ◽  
Type I ◽  
Melting Points ◽  
Liquid Silver ◽  
Pure Substances ◽  
Solid Liquid

The following paper is a continuation of two previous papers in which the melting- and freezing-point curves for two pairs of substances, each of which forms mixed crystals, have already been determined. In the first of these papers* mixtures of naphthalene and β -naphthol were examined and found to form a continuous series of mixed crystals and to give curves of Roozeboom’s Type I, in which the melting points of the pure substances.

Theoretical prediction of distribution coefficients of Sr2+ in nuclear waste/ionic liquid phases using COSMO-RS model

2014 ◽  
Vol 133 ◽  
pp. 138-148 ◽  
Author(s):  
Ankit Vishnoi ◽  
Tamal Banerjee ◽  
Pallab Ghosh ◽  
Sk. Musharaf Ali ◽  
K.T. Shenoy
Keyword(s):  
Ionic Liquid ◽  
Theoretical Prediction ◽  
Nuclear Waste ◽  
Distribution Coefficients ◽  
Liquid Phases

Calculation of the free Gibbs energy of phase transitions using solubility data. 1. The system Na2SO4-Na2Se04-H2O at 15 °C: Stable and metastable

2002 ◽  
Vol 74 (10) ◽  
pp. 1793-1800 ◽  
Author(s):  
Chr. Balarew
Keyword(s):  
Phase Transition ◽  
Gibbs Energy ◽  
Mixed Crystal ◽  
Distribution Coefficients ◽  
Mixed Crystals ◽  
Saturated Solution ◽  
Water Molecules ◽  
Free Gibbs Energy ◽  
Solubility Isotherms ◽  
Good Agreement

The solubility isotherms of the systems Na2SO4 ·10H2O–Na2SeO4·10H2O–H2O and Na2SO4·7H2O–Na2SeO4 ·7H2O–H2O have been investigated at 15 °C. It is established that discontinuous series of mixed crystals are formed in both systems. Two methods of calculation of the free Gibbs energy of phase transition at the interruption point of the solubility diagrams are used: (i) on the basis of the composition of the two mixed crystal types, which are in equilibrium with the saturated solution in the eutonic point of the system, and (ii) from the distribution coefficients between each of the mixed crystal phases and their saturated solution, using both experimentally obtained values and calculated distribution coefficients for ideal isomorphic mixing. The data found by the two methods exhibit very good agreement. It is established that the free Gibbs energy of the phase transition in the case of decahydrates is lower than in the case of heptahydrates. This fact is considered as a confirmation of the buffering action of water molecules with respect to the distortion of the crystal structures of the pure salts provoked by the formation of mixed crystals.

Distribution coefficients of 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane between aqueous and hydrocarbon liquid phases

2013 ◽  
Vol 86 (3) ◽  
pp. 398-403 ◽  
Author(s):  
D. A. Novikov ◽  
Yu. G. Dobryakov ◽  
N. A. Smirnova
Keyword(s):  
Distribution Coefficients ◽  
Hydrocarbon Liquid ◽  
Liquid Phases

scholarly journals On the spontaneous crystallisation and the melting- and freezing-point curves of two substances which form mixed crystals and whose freezing-point curve exhibits a transition point. -Mixtures of p -bromnitrobenzene and p -chlornitrobenzene

1913 ◽  
Vol 88 (602) ◽  
pp. 205-216
Keyword(s):  
Transition Point ◽  
Freezing Point ◽  
Mixed Crystals ◽  
Continuous Series ◽  
Type I ◽  
Melting Points ◽  
Freezing Points ◽  
Point Curve ◽  
Pure Substances

The following paper is a continuation of two previous papers in which the melting- and freezing-point curves for two pairs of substances, each of which forms mixed crystals, have already been determined. In the first of these papers mixtures of naphthalene and β -naphthol were examined and found to a form a continuous series of mixed crystals and to give curves of Roozeboom's Type I, in which the melting and freezing points of all mixtures lie between the melting points of the pure substances.

Crystallographic Evidence for the Formation of a Continuous Series of Mixed Crystals between NiO and LiNiO2

2003 ◽  
Vol 15 (4) ◽  
pp. 988-993 ◽  
Author(s):  
H. Wulff ◽  
M. Mohan Rao ◽  
F. Scholz
Keyword(s):  
Mixed Crystals ◽  
Continuous Series

scholarly journals On the spontaneous crystallisation and the melting and freezing point curves of mixtures of two substances which from mixed crystals and posses a minimum or eutectic freezing point. —Mixtures of azobenzene and benzylaniline

1910 ◽  
Vol 84 (571) ◽  
pp. 344-369 ◽  
Keyword(s):  
Freezing Point ◽  
Eutectic Point ◽  
Mixed Crystals ◽  
Continuous Series ◽  
Melting Points ◽  
Point Curve ◽  
Series Of Experiments ◽  
Pure Substances ◽  
New Feature

The behaviour of mixtures of naphthalene and β-naphthol has already been investigated, and the freezing and melting point curves and the curve of spontaneous crystallisation for these mixtures described.* These substances were found to form a continuous series of mixed crystals, on a curve of Roozeboom’s Type 1, the melting and freezing points of all the mixtures lying between the melting points of the pure substances. The behaviour of mixtures of monochloracetic acid and naphthalene was also investigated, for it was stated by Cady that these substances form mixed crystals of Roozeboom’s Type 5, whose melting and freezing point curves exhibit a minimum or eutectic freezing point. Experiments were therefore made with these substances with the object of determining the form of the curve of spontaneous crystallisation, or supersolubility curve, for mixtures of this type. No sign of the formation of any mixed crystals was observed, however, in a lengthy series of experiments, and it was shown that naphthalene and monochloracetic acid give the ordinary V-shaped freezing point curve for the solutions of two substances in each other, similar to that already obtained for mixtures of salol and betol,§ the only new feature being introduced by the existence of three modifications of monochloracetic acid. The monochloracetic acid and naphthalene mixtures having thus failed as an example of mixed crystals possessing a minimum or eutectic freezing point, another attempt was made to obtain a pair of substances with convenient melting points which form mixed crystals and possess the melting and freezing point curves with minimum eutectic point characteristic of Roozeboom’s Type 5.

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