Enthalpies of solution and solubilities of calcium chloride and its lower hydrates

doi:10.1016/0021-9614(85)90083-7

The Journal of Chemical Thermodynamics

Volume 17, Issue 9, September 1985, Pages 893-899

https://doi.org/10.1016/0021-9614(85)90083-7 Get rights and content

Abstract

New measurements on (CaCl₂ + rH₂O) in the temperature range 329 to 559 K have revealed the existence of a hydrate having $r = 13$ . This hydrate was characterized as to composition, X-ray diffraction pattern, and enthalpy of solution in water. For comparison, enthalpies of solution of the monohydrate, dihydrate, and anhydrous CaCl₂ were determined.

References (22)

R.L Montgomery et al.
J. Chem. Thermodynamics
(1977)
G Perachon et al.
Thermochim. Acta
(1978)
J.R Williams et al.
Thermochim. Acta
(1973)
W.W Wendlandt
Thermochim. Acta
(1975)
H.W.B Roozeboom
Z. Phys. Chem.
(1889)
U.S. Patent 3,878,295: 15 April...
CODATA Thermodynamic Tables. Tentative Selections for Some Compounds of Calcium and Related Mixtures. Garvin, D.;...
J.J Kessis
C.R. Paris
(1967)
R.F Schwenker et al.
C.E Vanderzee et al.
J. Phys. Chem.
(1961)

H.A Skinner et al.

Cited by (24)

Elucidating the effect of salt incorporation in tablets on tablet disintegratability
2024, International Journal of Pharmaceutics
The disintegration of tablets plays a crucial role in facilitating drug release, and disintegrants are used in tablet formulations to promote the disintegration process. This study aimed to explore and understand the impact of salt incorporation on tablet disintegratability. The study was designed to modulate the microenvironment temperature of tablets through dissolution of salts incorporated in the formulation, with the aim to facilitate tablet disintegration. It was observed that the incorporation of salts generally prolonged tablet disintegration. The impact of incorporating salts on tablet properties was both concentration-dependent and multi-factorial. The observed effect of salts on tablet disintegration was likely influenced by a combination of factors, including different properties of the salts, enhanced solubility of components, the temperature difference between the tablet and the disintegration medium, the expansion of air resulting from increased microenvironment temperature, and the competition for water between salts and disintegrants. These factors collectively contributed to the overall impact of salts on tablet disintegration.
Evaluation and selection of eutectic salts combined with metal foams for applications in high-temperature latent heat thermal energy storage
2024, Journal of Energy Storage
This study presents a systematic process for selecting eutectic salts for use in latent heat thermal energy storage (LHTES), and provides experimental evidence regarding their performance. One primary goal was to identify the most suitable eutectic salt for use with metallic foams over a temperature range of 450 °C–500 °C. Twenty one eutectic salts were preselected for comparison. The performance and cost-effectiveness of each were evaluated based on the Ragone relation, enabling a fair comparison of each salt's heat storage capacity and power density relative to cost. As a result, MgCl-NaCl, CaCl₂-NaCl, and FLiNaK were selected as the most promising candidates. Subsequently, experiments were performed to demonstrate the compatibility of the selected salts with metal foams while the copper and aluminum foams were immersed in the salts at 550 °C for 120 h. Combining C10100 (copper alloy) foam with CaCl₂-NaCl was observed to generate the least surface corrosion due to oxidation. The charge/discharge performance and thermal stability of CaCl₂-NaCl, both with and without the copper foam, were also tested to confirm the feasibility of this combination. The capsule with the copper foam showed enhanced performance (a 13 % reduced discharge rate) in comparison to the capsule without copper foam. The melting point of the CaCl₂-NaCl remained unchanged for 300-h duration of the cyclic melting/solidification experiments, and no thermal stability issues were observed.
Redox behaviour of CaCl<inf>2</inf> melts in presence of moisture as impurity. Part I: Cyclic voltammetry
2021, Journal of Electroanalytical Chemistry
Redox behaviour of CaCl₂ melt at 900 °C is well known; what is not completely established so far is how the voltammetric behaviour of melt would be in presence of moisture. CaCl₂ prepared from vacuum drying of CaCl₂.2H₂O retained some residual moisture that eventually led to formation of CaOHCl at 900 °C as a result of which two redox couples were observed in the cyclic voltammograms at tungsten electrode. In order to decipher whether the redox peaks were a reflection of formation of single electro-active species, CaCl₂.2H₂O and Ca(OH)₂ were added in pre-electrolysed CaCl₂ melts and those were again analysed by cyclic voltammetry. Enhancement of peak current density of redox peaks, which were observed in pre-electrolysed CaCl₂ melt, was seen. This was attributed to the increased concentration of CaOHCl in the melt in presence of CaCl₂.2H₂O and Ca(OH)₂. Subsequent to voltammetric peak analysis and logarithmic analysis of semi-integral curves for all melts, a mechanism involving formation of ${[{(CaOH)}_{2}^{2 +}]}_{adsorbed}$ undergoing a one-step two-electron transfer process in the first redox step was proposed. Second redox step resulted due to adsorption of $O^{2 -}$ on tungsten, and its peak current density also got enhanced due to addition of CaCl₂.2H₂O and Ca(OH)₂ in melt.
Effectiveness of water softening residuals as components of road deicing chemicals: Model analysis of freezing point depression
2021, Journal of Environmental Management
Citation Excerpt :
Magnesium salts have in general higher enthalpies of solution compared to calcium salts. For example, CaCl2 and MgCl2 are commonly used deicers with enthalpies of solution of −81.3 kJ/mol and −160 kJ/mol respectively (Sinke et al., 1985; Jahn and Wolf, 1993). The much lower magnesium content of sludge deicers in part explains the differences in ice melting rates of deicers produced from sludge compared to pure deicers.
Water softening residuals disposal is a worldwide issue due to the lack of effective reuse alternatives. The current principal disposal methods of landfilling and land application are quite costly due to the dewatering and transportation costs involved, and these operations can also cause potential environmental harm from leaching of the additives used in the treatment process. This research is aimed at the use of water softening residuals in the production of biodegradable road deicers that would be beneficial in replacing the highly corrosive and environmentally harmful chloride salts that are currently used for road deicing. Experimental data developed show that calcium magnesium acetate (CMA) and calcium magnesium propionate (CMP) deicers produced using water plant sludges are effective in deicing applications. A mathematical model is developed for predicting freezing point depression of CMA and CMP deicers as a function of molal concentration. The model predictions are found to match well with the experimental data, providing confidence in the use of this model for the effective design water softening sludge based deicers. The information developed herein provides options for the sustainable management of softening residuals and the concommitant mitigation of environmental harm associated with road deicing operations.
Thermodynamic modeling and phase diagram prediction of salt lake brine systems. I. Aqueous Mg2+–Ca2+–Cl− binary and ternary systems
2020, Chinese Journal of Chemical Engineering
Citation Excerpt :
Prutton in 1932 [5] determined the invariant equilibria at low temperatures: MgC12·12H2O + CaC12·6H2O + ice (− 52.2 °C), MgC12·12H2O + αMgC12·8H2O + CaC12·6H2O (− 20.7 °C), αMgCl2·8H2O + MgCl2·6H2O + CaC12·6H2O (− 6.7 °C). Kurnakov in 1938 [6] reported isotherms solubilities at 25 °C; Lightfoot in 1947 [7] determined isotherms at 35 and 75 °C; Assarsson in 1950 [8] reported a synopsis of the univariant equilibria from 40 to 115 °C and isotherm solubilities at 110 °C; and Sinke in 1985 [9] reported the solubilities of calcium chloride and its lower hydrates CaC12·nH2O (n = 0, 1/3, 1). Thermodynamic modeling of the phase equilibria in the last decades has become a major topic of investigation in order to interpolate or extrapolate the data gaps of multicomponent systems [10].
Salt lake brine is a complex salt-water system under natural environment. Although many models can express the thermodynamic properties and phase equilibrium of electrolyte aqueous solution, the multi-temperature characteristics and predictability are still the goals of model development. In this study, a comprehensive thermodynamic model system is re-established based on the eNRTL model and some improvements: (1) new expression of long-range electrostatic term with symmetrical reference state is proposed to handle the electrolyte solution covering entire concentration range; (2) the temperature dependence of the binary interaction parameters is formulated with a Gibbs Helmholtz expression containing three temperature coefficients, the liquid parameters, which associated with Gibbs energy, enthalpy, and heat capacity contribution; and (3) liquid parameters and solid species data are regressed from properties and solubility data at full temperature range. Together the activity coefficient model, property models and parameters of liquid and solid offer a comprehensive thermodynamic model system for the typical bittern of MgCl₂–CaCl₂–H₂O binary and ternary systems, and it shows excellent agreement with the literature data for the ternary and binary systems. The successful prediction of complete phase diagram of ternary system shows that the model has the ability to deal with high concentration and high non-ideality system, and the ability to extrapolate the temperature.
Simultaneous degradation and dechlorination of poly (vinyl chloride) by a combination of superheated steam and CaO catalyst/adsorbent
2020, Polymer Degradation and Stability
Citation Excerpt :
Under the superheated steam atmosphere in Fig. 7, there were presence of Ca(OH)2, CaClOH and CaCl2·6H2O as well as CaO. CaCl2·6H2O is formed only below 303 K as indicted in the phase diagram of calcium chloride and water [48], and calcium-containing chloride at the atmospheric temperature of 473 K exists as CaCl2 or CaCl2·1/3H2O [49,50]. CaCl2·6H2O is considered to be generated by the hydration process when the sample is cooled to the room temperature after the experiment.
In order to explore the possibility of efficient chlorine removal from the poly (vinyl chloride) (PVC) containing waste plastics, simultaneous degradation and dechlorination of PVC at a relatively low temperature was investigated by changing the atmosphere gas and metal oxide as catalyst and/or adsorbent (catalyst/adsorbent). 5.0 g of PVC and various metallic oxides such as CaO, Fe₃O₄, SiO₂, Al₂O, Ca(OH)₂, MgO were used under the superheated steam and nitrogen atmosphere of 473 K. The degradation rate of the PVC sample was small and the chlorine conversion to inorganic chloride was not observed without catalyst/adsorbent in the presence of either superheated steam or nitrogen atmosphere. Under the superheated steam atmosphere, the CaO catalyst/adsorbent resulted in much larger rates of degradation and dechlorination than any other metal oxides such as Fe₃O₄, SiO₂, Al₂O, Ca(OH)₂, MgO compared with nitrogen atmosphere. The calcium compounds such as CaCl₂, CaClOH and Ca(OH)₂ were formed in the sample by the combination of CaO catalyst/adsorbent and superheated steam. The rates of PVC degradation and chlorine conversion to inorganic chlorides were dramatically enhanced beyond the stoichiometric CaO amount for the CaCl₂ formation reaction with PVC under the superheated steam atmosphere.
The CaO addition contributed to both of the PVC degradation as a catalyst and the reactant with HCl as an adsorbent, whereas the superheated steam played a role of the sample temperature increase to promote the PVC degradation through the exothermic reaction with CaO.

View all citing articles on Scopus

View full text

Article preview

The Journal of Chemical Thermodynamics

Abstract

References (22)

J. Chem. Thermodynamics

Thermochim. Acta

Thermochim. Acta

Thermochim. Acta

Z. Phys. Chem.

C.R. Paris

J. Phys. Chem.

Cited by (24)

Elucidating the effect of salt incorporation in tablets on tablet disintegratability

Evaluation and selection of eutectic salts combined with metal foams for applications in high-temperature latent heat thermal energy storage

Redox behaviour of CaCl<inf>2</inf> melts in presence of moisture as impurity. Part I: Cyclic voltammetry

Effectiveness of water softening residuals as components of road deicing chemicals: Model analysis of freezing point depression

Thermodynamic modeling and phase diagram prediction of salt lake brine systems. I. Aqueous Mg<sup>2+</sup>–Ca<sup>2+</sup>–Cl<sup>−</sup> binary and ternary systems

Simultaneous degradation and dechlorination of poly (vinyl chloride) by a combination of superheated steam and CaO catalyst/adsorbent