Focusing on transport of heavy metals in gas phase, this review allows an i
nsight into the complex physical-chemical processes taking place during com
bustion and cooling. As heavy metal emission is frequently correlated with
particulate matter, morphological, mineralogical, and chemical properties o
f fly ash particles are introduced as well as evaporation-condensation proc
esses. Metal reactions in high temperature zones with thermodynamic modelin
g of the chemistry in high temperature systems were investigated by several
research groups. Analyses concerning the distribution and deposition behav
ior of heavy metals involved in laboratory-scale combustion tests, full-sca
le incineration plants, and real fire accidents as well as full-scale simul
ations of the latter were done.