Heavy metal (HM) vaporization dynamics in a circulating fluidized bed (CFB) riser was numerically analysed based on a Lagrangian approach. Simulation was performed by combining an HM vaporization model and a Lagrangian model developed for CFB, coupled by including the HM transport equation in gas flow. CdCl2/Al2O3 was chosen as typical HM/mineral matrix system in the model. The simulation results address the HM vaporization dynamics of a particle, the heterogenous particle flow structures, and the HM distribution in the CFB riser. The particle heterogeneous distribution affects significantly the HM concentration distribution in the riser. (C) 2004 Elsevier B.V. All rights reserved.