Phase transitions and surface property variations of bastnaesite in suspension roasting: A study of bastnaesite pyrolysis and cerium oxidation

• Suspension roasting achieves rapid bastnaesite decomposition with simultaneous cerium oxidation, yielding CO2, Ce7O12, La2O3, CeF3, and LaF3 as products. • Prolonged roasting initially increases surface cracks, porosity, and BET specific surface area, but later particle fusion and pore consolidation reduce specific surface area. • Both bastnaesite pyrolysis and cerium oxidation follow Avrami–Erofeev kinetic models; reaction order decreases with temperature, and activation energy is higher at lower temperatures. • The study provides mechanistic insights and kinetic parameters essential for optimizing suspension roasting technology in bastnaesite smelting and rare earth extraction.