Mechanism and kinetics of thermal decomposition of dysprosium oxalate with six water

Rare earth oxalates are the common precursors for preparing rare earth oxides, especially rare earth oxides with controlled particle size, which have the advantages of good precipitate crystal form, easy filtration and decomposition, etc. However, kinetic study of the thermal decompositionforcurrent rare earth oxalates was less, Therefore, thethermogravimetry-differential thermal analysis method was used to study the thermal decomposition process of dysprosium hexahydrate. The decomposition kinetics parameters of dysprosium hexahydrate were calculated by Kissinger, Ozawa and Crane methods. Coats-Redfern method was used to find the mechanism function of the reaction.The results showed that the decomposition activation energies calculated by several methods were quite close and the thermal decomposition of dysprosium hexahydrate was carried out in two steps. The first step was the first order dehydration reaction. The reaction mechanism function was F1, The activation energy was 62.48 kJ/mol and the pre-exponential factor was 1.84×10⁶. The second step was also the first-order decomposition reaction. The reaction mechanism function was F2. The apparent activation energy was 106.42 kJ/mol and the pre-exponential factor was 2.79×10⁷.