Hydrogen chloride (HCl) absorption by raw meal and raw meal compounds, using in-situ HCl generation and TGA-FTIR tests

HCl emission control optimization from cement plants requires a quantification of the HCl absorption capacity of raw meals (mixtures of fine particles of raw materials) and the determination of raw meal constituent effects on HCl capture below 400 ℃. This work reports lab data obtained by ramping temperature tests using a standard TGA-FTIR set-up, a thermally degradable solid HCl source (AlCl₃ 6H₂O), industrial raw meals, and mixtures of reagent grade raw meal constituents (SiO₂, CaCO₃, Fe₂O₃, and Al₂O₃). The lab data showed that industrial raw meals had significantly higher HCl absorption capacity than reagent grade CaCO₃. The presence of Fe₂O₃ promoted HCl capture by CaCO3 between 90 ℃ and 350 ℃. The HCl absorption by raw meals was higher when the HCl source was dispersed rather than when it was placed below the raw meals.