Pyrolysis mechanism of bastnaesite during roasting in N2 atmosphere: An in-situ study of gas products, phase transition, and kinetics

Abstract

The application of suspension magnetization roasting technology in ferruginous rare earth bearing ore has gained significant attention. Bastnaesite, due to its pyrolysis characteristics, has been proposed as a reductant for iron minerals. In this study, the pyrolysis of bastnaesite was investigated through various in-situ methods. The results showed that during pyrolysis, CeOF and CO₂ were first generated, followed by the reaction of CO₂ with Ce₂O₃ and Ce₇O₁₂ to produce CO. Pyrolysis occurred initially on the particle surface and then progressed inward. Increasing the roasting temperature promoted the pyrolysis of bastnaesite and CO generation. The addition of CO₂ during the roasting process enhanced the formation of CO. The pyrolysis kinetic mechanisms under isothermal and non-isothermal conditions were phase-boundary controlled reaction mechanism (n = 4) and phase-boundary controlled reaction mechanism (n = 2–4), respectively. This detailed analysis of the pyrolysis behavior of bastnaesite facilitates the efficient and low-carbon development of ferruginous rare earth ores through suspension magnetization roasting.