A new analytical model has been presented for spherical flame propagation in organic dust-air mixtures. This method assumes a quasi-steady state flame propagation. The flame structure consists of a preheat zone, a reaction zone, and a post-flame zone for lean mixture. Radiation, conduction, and convection are the three flame propagation mechanisms considered in this model. Flame speed and temperature are calculated; and by adding the radiation term, it is observed that the flame temperature in the preheat zone and the flame speed both increase. This phenomenon may be attributed to the radiative heat transfer from the flame zone to the preheat zone. The flame temperature in the reaction zone increases with the reduction of particle size and the increase of dust concentration. Also, the increase of flame radius results in the increase of flame speed. (C) 2015 Elsevier B.V. All rights reserved.