Thermal decomposition of alkaline-earth carbonate samples of extreme thickness

Forward and reverse reactions were studied of the type MCO₃ = MO+CO₂, (M = Mg, Ca, Sr and Ba). The samples were of three types: (1) thick (some mm) crystals; (2) powders; (3) thin layers (about 10 nm).Pressure—temperature data of the reactions are reported from the point of view of reversibility and equilibrium. The effect of repeated isothermal reaction cycles resulted in decreasing conversion of CO₂ uptake.Isothermal and non-isothermal thermal measurements were completed with studies on an electron microprobe analyzer to explain the results.