A numerical model for the ignition and combustion of lithium particles (d(p) = 20-250 mu m) in pure CO2 atm(o)sphere was developed and implemented in ANSYS Fluent's "discrete phase model". The combustion model is based on experimental findings gained in a laminar flow reactor: the experiments indicate two reaction mechanisms: An initial high temperature above gas-phase combustion (>2500 K) with a reaction zone apart from the particle surface ("stand-of flame") followed by a surface reaction at lower temperature (1500-1800 K). As reaction kinetics is only available for the surface reaction, a theoretical approach was established to calculate duration and mass conversion of the gas-phase reaction. The complete model includes inert heating, lithium melting and the reaction steps described above and enables the complete calculation of single particle or droplet combustion of lithium. The results of the numerical simulation were compared to experiments conducted in a laminar flow reactor. As the numerical results show, the predicted combustion behavior is in good agreement with the experimental results. (C) 2015 Published by Elsevier Ltd.