Abstract
Calorimetric measurements of sodium chloride dihydrate NaCl·2H2O (mineral name hydrohalite) were carried out with using DSC. Heat capacity from 190 to 250 K was measured and found to increase from 109 to 137 J mol−1 K−1. The enthalpy of formation of hydrohalite from solid ice and halite at 273.15 K was derived from the thermal effect of melting/decomposition in DSC measurements and found to be close to − 1.8 kJ mol−1. The same DSC results show clearly that the upper temperature limit for the existence of hydrohalite is several degrees greater than the current value of 273.15 K accepted for the peritectic decomposition of hydrohalite. The phase diagram of the NaCl–H2O system needs correction.
Original language | English |
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Pages (from-to) | 2555-2562 |
Number of pages | 8 |
Journal | Journal of Thermal Analysis and Calorimetry |
Volume | 140 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1 Jun 2020 |
Keywords
- DSC
- Enthalpy of formation
- Heat capacity
- Hydrohalite
- SEA-ICE
- SYSTEM
- THERMODYNAMIC PROPERTIES
- PHASE
- THERMAL-ENERGY STORAGE