Thermal stability of potassium carbonate near its melting point

Richard L. Lehman, Jefffery S. Gentry, Nick G. Glumac

Research output: Contribution to journalArticlepeer-review


The behavior of potassium carbonate was studied by thermal analysis near its melting point under 1 atm total pressure. Literature data are scant regarding the degree to which K2CO3 decomposes in sub- and pro-liquidus thermal environments, and reliable thermodynamic data are not available for the reaction K2CO3⇌K2O+CO2 in the temperature range of interest. TGA and DTA analyses indicate that significant volatilization occurs below the melting point and the logarithm of the rate of volatilization is a linear function of 1/T above the melting point. The effect of CO2 partial pressure was highly significant in reducing, but not eliminating, volatilization near the melting point. Graphs of ln[PCO2×weight loss rate] vs. (1/T) were linear, supporting a decomposition model rather than congruent volatilization. The melting point of K2CO3, as measured by DTA, is 905°C in CO2 and 900°C in N2.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalThermochimica Acta
Issue number1
StatePublished - May 26 1998
Externally publishedYes


  • Decomposition
  • KCO
  • Melting behaviour
  • Potassium carbonate

ASJC Scopus subject areas

  • Instrumentation
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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