CaCl2(aq) at elevated temperatures. Enthalpies of dilution, isopiestic molalities, and thermodynamic properties

Holmes, H.F.; Busey, R. H.; Simonson, J.M.; Mesmer, R.E.

doi:10.1016/0021-9614(94)90005-1

Cited by 59 publications

(92 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Holmes et al [9] found that authors frequently claimed both higher accuracy and precision of aqueous calcium chloride densities than implied when the data were compared to other sources. In particular, as reported by Monnin [8], Kumar and Atkinson [37] stated an error of less than 5 ppm in their CaCl 2 (aq) density measurements, whereas Monnin's fit of the data indicated it to be closer to 400 ppm.…”

Section: Discussionmentioning

confidence: 99%

“…[1] <68.5 298-473 6.0 [2] 0.1-60 273-523 6.0 [5] 0.1-60 298-398 6.0 [4] 0.1-40 273-523 6.15 [9] 0.1-40 270-526 4.6 [7] 0. authoritative datasets, there is now a sufficient number of independent property values not only to test the goodness-of-fit of theoretical models but also to assess realistically the experimental uncertainty and thus to avoid more degrees of freedom than are warranted in the model-fitting process.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

Rowland

May

2013

Fluid Phase Equilibria

View full text Add to dashboard Cite

Rowland, D. and May, P.M. (2013)AThis is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Abstract A comprehensive characterization of densities / apparent molar volumes for the aqueous solutions of magnesium chloride, calcium chloride and potassium iodide to high temperatures and pressures has been performed based on the Pitzer equations. The unusual availability of overlapping high quality independent sets of experimentally measured data for these systems allows the relevant thermodynamic quantities to be calculated with a high degree of confidence over wide ranges of conditions (< 8 mol/kg; 273-573 K; 0.1-100 MPa). A realistic assessment of experimental uncertainty indicates that an adequate description of volumetric behaviour is achieved by the standard Pitzer model without extensions. The experimental accuracy implied by differences between independent observers, however, is more than one order of magnitude worse than typically-claimed estimates of experimental precision.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

Rowland

May

2013

Fluid Phase Equilibria

View full text Add to dashboard Cite

show abstract

“…Other extensions have increased the number of virial terms (Ananthaswamy and Atkinson, 1985) or introduced a temperature-dependent α 1 parameter (Holmes et al, 1997). The additional flexibility of these extended equations can be problematic: extra parameters make the optimisation numerically more complicated (Holmes et al, 1994;Pitzer et al, 1999) and models can no longer be combined consistently (Clegg and Whitfield, 1991). Many other variations of Pitzer's original equations have been presented in the literature, including forms with electrolyte-specific b (Pérez-Villaseñor et al, 2002) or on the mole fraction basis (Pitzer and Simonson, 1986).…”

Section: Comparison Between the Standard Pitzer Equations Variants Omentioning

confidence: 99%

“…The upper temperature limit, T ≤ 523 K, was imposed on MgCl 2 (aq) and CaCl 2 (aq) because of well-known difficulties in the data at higher temperatures (Holmes et al, 1994;Holmes and Mesmer, 1996). Several factors were considered in choosing suitable upper concentration limits, including the number of data available and the best-fitting concentration limit at ambient temperature .…”

Section: This Case Study Confirms As Is Well Known That the Pitzer mentioning

confidence: 99%

“…While these differences exceed the likely experimental uncertainties, they are small and it is difficult to know their true significance. The standard deviations of the fit to Spedding (1977), Goldberg and Nuttall (1978), Ananthaswamy and Atkinson (1985), Holmes et al (1994) and Gruszkiewicz and Simonson (2005). The MgCl 2 (aq) system was selected for this Case Study as it is known to be reliably represented at T ≤ 523 K using the standard Pitzer equations (Case Study A above).…”

Section: Cacl 2 (Aq)mentioning

confidence: 99%

See 1 more Smart Citation

Aqueous electrolyte solution modelling: Some limitations of the Pitzer equations

Rowland

Königsberger

Hefter

et al. 2015

Applied Geochemistry

View full text Add to dashboard Cite

Despite intense efforts, general thermodynamic modelling of aqueous electrolyte solutions still presents a difficult challenge, with no obvious method of choice. Even though the Pitzer equations seemingly provide a well-established theoretical framework applicable to many chemical systems over a wide range of temperatures and pressures, they are not as widely adopted as their early promise might have suggested. This is strikingly illustrated by the simultaneous appearance in the literature of numerous, different (and potentially incompatible) Pitzer models alongside a proliferation of alternative theoretical approaches with inferior capabilities.To better understand this problem, the ability of the Pitzer equations to represent the physicochemical properties of aqueous solutions has been systematically investigated for exemplar electrolyte systems. Pitzer ion-interaction parameters have been calculated for selected systems by least-squares regression analysis of published solution data for activity coefficients, osmotic coefficients, relative enthalpies, heat capacities, volumes and densities to high temperatures and pressures. Although satisfactory fits can be achieved when the ranges of conditions are carefully chosen and when sufficient data are available to constrain the regression, the fits obtained tend otherwise to be unsatisfactory. The Pitzer equations do not cope well with gaps and other deficiencies in the regressed data. Profound difficulties, poorly recognized hitherto, can also arise because of variation in the sensitivity of the Pitzer functions to values for different physicochemical properties when these are combined. Given the dimensionality of numerous related thermodynamic properties, all changing as functions of composition, temperature and pressure, these problems are difficult to detect, let alone address, especially in multicomponent systems. The growing practice of improving fits simply by adding basis functions (thereby increasing the number of adjustable parameters) should be deprecated because it increases the likelihood of error propagation, introduces subjectivity, makes independent verification difficult and has deleterious implications for both automated data processing and for consistency between thermodynamic models.

show abstract

Calorimetric Properties of Hydrothermal Solutions

Valyashko

Gruszkiewicz

2008

Hydrothermal Experimental Data

View full text Add to dashboard Cite

CaCl2(aq) at elevated temperatures. Enthalpies of dilution, isopiestic molalities, and thermodynamic properties

Cited by 59 publications

References 60 publications

A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

Aqueous electrolyte solution modelling: Some limitations of the Pitzer equations

Calorimetric Properties of Hydrothermal Solutions

Contact Info

Product

Resources

About