DETERMINATION OF AS, CD, CR, AND PB SPECIES FORMED IN A COMBUSTION ENVIRONMENT

To facilitate the understanding of the fate of metals during incineration the speciation of metals is critical. Thus, an experimental study to determine the speciation of metals during incineration was performed. Aqueous metal salts of arsenic, cadmium, chromium, and lead were injected into a laboratory reactor, post-flame. Aerosols were captured on a glass fiber filter by isokinetic sampling. Reactor temperature was varied from 600 to 1100 degrees C and the stoichiometric ratio was varied from 0.95 to 1.25. The Reference Intensity Method (RIM) of quantitative X-ray diffraction analysis combined with X-ray transmission was utilized to determine the speciation of aerosols removed from the combustion environment. The results indicate that temperature and stoichiometric ratio affect the formation of crystalline compounds in the combustion environment. Injection of different compounds of the same metal into the furnace resulted in the formation of different products. RIM was used to determine the composition of the crystalline sample fraction when reference intensity ratios were available.