Abstract: To promote the efficient utilization of iron-bearing rare earth ores,the thermal decomposition behavior and reaction
mechanism of bastnaesite in a CO atmosphere were investigated. The results indicate that CO₂ is the main gaseous product
during decomposition,and its release rate increases with temperature,indicating accelerated reaction kinetics at elevated
temperatures. Bastnaesite first decomposes to form REOF under a CO atmosphere,followed by oxidation in air to produce REF₃
and Ce₇O₁₂. The decomposition process significantly disrupts the particle structure,leading to the formation of elongated cracks
and abundant micropores,increased porosity,and partial fragmentation into finer particles. Isothermal kinetic analysis reveals
that the reaction follows a random nucleation and subsequent growth model (n =2),with the kinetic function g(α) = [ - ln(1
- α)]^{1/ 2} and an apparent activation energy of 74. 05±5. 61 kJ/ mol. These findings provide theoretical support for optimizing
the “reduction roasting-magnetic separation-flotation” process in the development of iron-bearing rare earth resources.