Non-isothermal studies on mechanism and kinetics of thermal decomposition of cobalt(II) oxalate dihydrate

摘要

Thermal decomposition of CoC_2O_4·2H_2O was studied using DTA, TG, QMS and XRD techniques. It was shown that decomposition generally occurs in two steps: dehydration to anhydrous oxalate and next decomposition to Co and to CoO in two parallel reactions. Two parallel reactions were distinguished using mass spectra data of gaseous products of decomposition. Both reactions run according to Avrami-Erofeev equation. For reaction going to metallic cobalt parameter n = 2 and activation energy is 97 ± 14 kJ mol~(-1). It was found that decomposition to CoO proceeds in two stages. First stage (0.12 < α_(II) < 0.41) proceeds according to n = 2, with activation energy 251 ± 15 kJ mol~(-1) and second stage (0.45 < α_(II) < 0.85) proceeds according to parameter n = 1 and activation energy 203 ± 21 kJ mol~(-1).