Évolution physico-chimique de particules d'aérosols dans les panaches industriels en cheminée et dans l'environnement au sein du périmètre d'un site métallurgique

Abstract

Aerosol samplings were performed inside the chimneys and in the environment of a FeMn alloys manufacturing plant. A LIDAR device was used to follow the transport of emitted plumes. To analyze aerosols evolution, a Scanning Mobility Particle Sizer (SMPS) and an Optical Particle Counter (OPC) were combined to short-term aerosol samplings at increasing distances from the source (0-2000 m). The bulk concentrations of the refractory fraction were measured by mass spectrometry (ICP-MS) and the elemental composition of individual particles was obtained by electron microanalysis (automated SEM-EDX). By contrast with upwind measurements, the particle size distributions obtained downwind the plant highlight enrichment in ultrafine particles (10-100 nm). Individual analysis of particles collected inside the plume shows a high proportion of Mn-/Fe-bearing particles constituted of internally mixed aluminosilicate and metallic compounds. They evolve rapidly after emission by adsorption of VOCs gas and sulfuric acid emitted by the plant but also by agglomeration with pre-existing particles.