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.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Melting behaviour
- Potassium carbonate