Miscibility Gaps in Fused Salts

Margheritis, Chiara; Flor, Giorgio; Sinistri, Cesare

doi:10.1515/zna-1973-0813

Cited by 39 publications

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“…When y = 0, Equation (5) reduces to Equation (4). Setting ∂G/∂y = 0 results in an equilibrium constant which, when G E = 0, is given by:…”

Section: Thermodynamic Models and Databases For Slags Fluxes And Saltsmentioning

confidence: 99%

“…Consider the CaO-MgO-SiO 2 system whose liquidus projection is shown in Figure 3. In very basic slags, it is well established that the principal ionic species present are Ca 2+ , Mg 2+ , O 2-and SiO 4 4-ions. If we join the compositions corresponding to CaO, MgO, Ca 2 SiO 4 and Mg 2 SiO 4 by straight lines in Figure 3 we define a trapezoid, which is similar to a reciprocal salt composition square as in Figure 1.…”

Section: Slagsmentioning

confidence: 99%

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Thermodynamic models and databases for slags, fluxes and salts

Pelton¹

2005

Mineral Processing and Extractive Metallurgy

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The evolution of thermodynamic models of molten salts and slags, starting with Temkin in 1948, has culminated in today's sub-lattice models. These modern models have permitted the development of large thermodynamic databases of model parameters, which can be used to calculate and predict accurately the properties of multicomponent solutions. The model parameters are mainly obtained by the critical evaluation and optimisation of available thermodynamic and phase equilibrium data for binary and ternary subsystems. The models are then used to estimate the properties of multicomponent slags and salts from these assessed binary and ternary parameters. When used in conjunction with thermodynamic databases for solids and solid solutions (salts, oxides, sulphides, metals, etc.), other liquid solutions (such as liquid metals), and gases, these databases permit the calculation of complex multiphase equilibria in multicomponent systems, with applications in a wide variety of industries. These calculations can be performed with general commercial software for Gibbs energy minimisation, which can also be incorporated into process simulation software packages. .za; Web: www.saimm.co.za). Published by Maney on behalf of the Institute.

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“…When y = 0, Equation (5) reduces to Equation (4). Setting ∂G/∂y = 0 results in an equilibrium constant which, when G E = 0, is given by:…”

Section: Thermodynamic Models and Databases For Slags Fluxes And Saltsmentioning

confidence: 99%

Section: Slagsmentioning

confidence: 99%

Thermodynamic models and databases for slags, fluxes and salts

Pelton¹

2005

Mineral Processing and Extractive Metallurgy

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“…The phase equilibria in liquids at 1000 ~ were characterized as follows: Agl was usually sealed in a quartz tube with the desired amount of a Ag20-B203 glass (or of the stable AgI-Ag20-B203 compound with the lowest Agl content). Direct visual observation of the test-tube at different temperatures was made with an apparatus described elsewhere [8]. X-ray powder diffractometry and differential thermal analysis (DTA) techniques were routinely [4] applied to the samples.…”

Section: Experimental Methodsmentioning

confidence: 99%

Stable and metastable phases in Agl-containing silver borate glasses

Chiodelli

Flor

Magistris

et al. 1983

Journal of Thermal Analysis

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This paper studies the thermal stability and the glass formation region the AgI-Ag20--B203 system. The miscibility range of the components has been investigated by direct visual observation at 1000~ i.e. where the system is liquid over the entire compositional range. By combining X-ray and differential thermal analysis (DTA) measurements, the large region of glass formation of the system has been determined. The dependence of the glass transition temperature upon the glass composition is discussed. Series of glasses have been annealed over extended time intervals above the glass transition temperature in order to characterize the "equilibrium" phase diagram for the system. Analysis of the annealed materials shows that several crystalline compounds form upon annealing.Glasses have tong been materials of choice for technological applications, and have recently become the object of fundamental researches in the field of condensed matter. Many efforts are devoted to characterizing the "structure" and thermal stability of glass systems, in the hope of finding the key to the understanding of the "universal" properties of disordered materials [1]. This paper presents an investigation of the system AgI-Ag20-B20 3, which has been undertaken with the aim of providing a well-characterized model system suitable for basic researches. While there is an enormous literature on the subject of glasses made of boron and metal oxides [2], relatively little is known on the ternary systems containing monovalent halides. However, the interest of these compounds is enhanced by their unusual ion transport properties in the solid state [3][4][5][6][7]. Ion conductivity studies allow the selection of technologically promising materials, while providing an aspect of glass dynamics which is not yet fully understood.Structural studies on borate glasses nave a long tradition [2] and several structural "groups" have been identified in the borates. However, this knowledge does not enable us to predict many physical properties of the glasses, even when specific assumptions, such as those introduced by the random network model [2], are made. The reason for the partial failure of the Zachariasen model is that correlations exist between the orientations of adjacent structural units, or that the glass is not "perfectly 4*

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“…The symmetry can be improved if the temperature dependence of the interaction parameters of the binary mixtures is taken into account.Detailed measurements of the liquid-liquid (LL) equilibria in reciprocal ternary systems are highly desirable both to complete basic data and to be used as particularly sensitive tests of current theories for ionic systems.The solid-liquid (SL) equilibria of the reciprocal ternary system K, Li/Br, F were reported by Volkov and Dubinskava [1] in 1953, whereas the LL equilibria were studied only along the stable diagonal (LiF + KBr) and reported in Note VII of this series [2].The present paper gives a complete experimental analysis of the SL and LL equilibria taking into account the full range of compositions and temperatures. Moreover, the results of the conformal ionic solution (CIS) theory [3] when applied to this system along with a discussion of the applicability limits of the theory are reported.…”

mentioning

confidence: 87%

“…The solid-liquid (SL) equilibria of the reciprocal ternary system K, Li/Br, F were reported by Volkov and Dubinskava [1] in 1953, whereas the LL equilibria were studied only along the stable diagonal (LiF + KBr) and reported in Note VII of this series [2].…”

mentioning

confidence: 99%

Miscibility Gaps in Fused Salts. Note X. The Reciprocal Ternary System K, Li/Br, F

Margheritis

Flor

Sinistri

1979

Zeitschrift Für Naturforschung A

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Solid-liquid and liquid-liquid equilibria in the reciprocal ternary system K, Li/Br, F were fully measured.The projection of the miscibility gap occupies 20.8% of the composition square; the upper critical point of the gap is along the stable diagonal at 953 °C and £LiF = 0.70.Attempts to predict the liquid-liquid equilibria by means of the conformal ionic solution theory using temperature independent interaction parameters lead to an incorrect symmetry of the gap. The symmetry can be improved if the temperature dependence of the interaction parameters of the binary mixtures is taken into account.Detailed measurements of the liquid-liquid (LL) equilibria in reciprocal ternary systems are highly desirable both to complete basic data and to be used as particularly sensitive tests of current theories for ionic systems.The solid-liquid (SL) equilibria of the reciprocal ternary system K, Li/Br, F were reported by Volkov and Dubinskava [1] in 1953, whereas the LL equilibria were studied only along the stable diagonal (LiF + KBr) and reported in Note VII of this series [2].The present paper gives a complete experimental analysis of the SL and LL equilibria taking into account the full range of compositions and temperatures. Moreover, the results of the conformal ionic solution (CIS) theory [3] when applied to this system along with a discussion of the applicability limits of the theory are reported.The apparatus, the experimental techniques and the characteristics of the employed salts were described in previous papers [4], Figure 1 shows the SL equilibria, along with the coordinates of the eutectics, of the four binaries. Figure 2 reports the SL and LL equilibria along the unstable diagonal (KF + LiBr) and the stable one (LiF + KBr): the area in which demixing occurs is shaded. As regards the unstable diagonal, the primary crystallization temperature (PCT) varies from 801 °C (x LiB r = 0.41) to 798 °C (x Li Br = 0.59) going through a maximum at 822 °C (^LiBr = 0.50); the point of maximum of the miscibility gap is at 930 °C (#LiBr = 0.50). ResultsThe stable diagonal was fully described inThe general topology of the system K, Li/Br, F is shown in Figure 3. Figure 3a reports the projection of the 12 studied cuts along with various significant temperatures. The stratification lens (dashed) impinges on the LiF crystallization field and occupies 20.8% of the square. The main axis of the lens coincides with the principal diagonal, and along this axis the PCT is constant at 822 °C. The system presents two ternary eutectics at 320 °C OzLiF = 0.03 5 ; *LiBr = 0.54 5 ; ^KBr = 0.42) and at 465 °C (£LiF = 0.07s; ^KBr = 0.60s; £kf = 0.32), respectively.The comparison of the present results with the ones in Ref. [1] shows only a qualitative topological agreement, the numerical data being in some cases quite different. The invariant point E-i. for instance, is reported in Ref.[1] as a peritectic point at 558 °C (x LiF = 0.05; x KB r = 0.545; X K F = 0.395). DiscussionAmong the recent applications of the CIS theory the a priori predic...

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Miscibility Gaps in Fused Salts

Cited by 39 publications

References 0 publications

Thermodynamic models and databases for slags, fluxes and salts

Thermodynamic models and databases for slags, fluxes and salts

Stable and metastable phases in Agl-containing silver borate glasses

Miscibility Gaps in Fused Salts. Note X. The Reciprocal Ternary System K, Li/Br, F

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