Modelling of heavy meal vaporisation from a mineral matrix

This study deals with the fundamental aspects of the volatilisation of heav y metals (HM) during municipal solid waste (MS W) incineration. The thermal treatment of a model waste was theoretically and experimentally studied in a fluid-bed. A mathematical model was developed to predict the fate of met allic species according to the main phenomena controlling the process: heat and mass transfer (transport phenomena), chemical reactions involving HM, and mechanism of vapour metal species sorption inside the porous matrix. Th e model assumes local thermodynamic equilibrium between the vapour and the metal compound on the substrate in the pores of a particle. This approach p ermits to predict the extent of HM vaporisation from a mineral porous matri x when its physical properties are known. Experimental data concerning CdCl 2 release from an alumina matrix in a 850 degreesC fluidised bed are in goo d agreement with theoretical results. (C) 2001 Elsevier Science B.V All rig hts reserved.