Determination of the eutectic solubility lines of the ternary system NaHCO3-Na2CO3-H2O

Marcos Rodriguez Pascual*, Daniela Trambitas, Elisa Saez Calvo, Herman Kramer, Geert-Jan Witkamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


A crystallizer was built and a procedure developed to accurately measure the eutectic solubility lines where ice and salt coexist in equilibrium with the solution, for potential application of Eutectic Freeze Crystallization. The eutectic solubility lines of the ternary system NaHCO3-Na2CO3-H2O were determined experimentally and calculated with the extended UNIQUAC model. The extended UNIQUAC model describes the experimental data quite well. Anhydrous NaHCO3 and Na2CO3·10H2O were the only two types of crystals present in equilibrium with ice crystals in the ternary system. At the quadruple point NaHCO3 and Na2CO3·10H2O are in equilibrium with a solution of about 4.34wt% of Na2CO3 and 4.77wt% of NaHCO3 at -3.32°C. The anhydrous NaHCO3 crystals were needle shaped with lengths between 5 and 10μm, that were agglomerated into particles of about 100-300μm, while the Na2CO3·10H2O crystals were hexagonally shaped with sizes between 100 and 500μm.

Original languageEnglish (US)
Pages (from-to)1365-1371
Number of pages7
JournalChemical Engineering Research and Design
Issue number10
StatePublished - Oct 1 2010


  • Crystallization
  • Eutectic Freeze Crystallization
  • Mathematical modelling
  • Phase diagram
  • Precipitation
  • Solubility

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering


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