Laboratory experiments were performed by exposing limestone samples to the corrosive action of S02 (1 ppmv) and N02 (6ppmv) at constant temperature (25°C), relative humidity (about 100%) and dynamic flow conditions (300cc/min) within a testing apparatus simulating dry deposition of pollutants. The obtained results point to a marked slowdown of the sulphation process in the short time and to an apparent resumption of sulphation after about twenty days from the beginning of the experiments. The trend of the experimental points was approximated by means of two different fitting curves, with logarithmic form in the initial stage and simple linear form in the subsequent stage. This led to some considerations on the relative rates of formation of the reaction products, calcium sulphite hemihydrate and gypsum, at different pollutants concentrations. A multistep genetic model was formulated by taking into account the influence of nucleation and growth of the reaction products in the progress of sulphation.
Corrosion of limestone in humid air containing sulphur and nitrogen dioxides: a model study
MORONI, Beatrice;POLI, Giampiero
2000
Abstract
Laboratory experiments were performed by exposing limestone samples to the corrosive action of S02 (1 ppmv) and N02 (6ppmv) at constant temperature (25°C), relative humidity (about 100%) and dynamic flow conditions (300cc/min) within a testing apparatus simulating dry deposition of pollutants. The obtained results point to a marked slowdown of the sulphation process in the short time and to an apparent resumption of sulphation after about twenty days from the beginning of the experiments. The trend of the experimental points was approximated by means of two different fitting curves, with logarithmic form in the initial stage and simple linear form in the subsequent stage. This led to some considerations on the relative rates of formation of the reaction products, calcium sulphite hemihydrate and gypsum, at different pollutants concentrations. A multistep genetic model was formulated by taking into account the influence of nucleation and growth of the reaction products in the progress of sulphation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
