Decomposition Study of Praseodymium Oxalate as a Precursor for Praseodymium Oxide in the Microwave Field

Abstract

Micron-sized praseodymium oxide powders are prepared successfully from the praseodymium oxalate in a microwave field at 750 °C for 2 h in the present study. X-ray diffraction (XRD) analysis demonstrates that the presence of cubic structured crystalline Pr ₆O ₁₁ and complete decomposition of the precursor are confirmed by Fourier transform infrared (FT-IR) analysis. The scanning electron microscopy (SEM) results show yield powders with the desired particle size and uniform morphologies. Particle size analysis demonstrates that the median diameter ( D ₅₀) becomes stable at 750 °C. The D ₅₀, average surface area, pore diameter, and pore volume calculated by Brunauer −Emmett–Teller (BET) are 4.32 μm, 6.628 m ²/g, 1.86 nm, and 0.026 cm ³/g at 750 °C for 2 h, respectively. Moreover, loss on ignition (L.O.I.) analysis indicates that the L.O.I. is as low as 0.39%, meeting the enterprise requirement (<1%). In comparison, conventional calcination experiments are carried out in the electric furnace. Both XRD and FT-IR analyses are in consistence with thermogravimetry–differential scanning calorimetry, which indicates that the temperature required for the decomposition of praseodymium oxalate hydrate is higher than that of microwave heating. Furthermore, SEM, particle size distribution, and BET analysis indicate that agglomeration generates, particle size enlarges, and average surface area increases. In all, it is confirmed that preparing rare-earth oxides from rare-earth oxalates is feasible using microwave heating to replace conventional heating.