ABSTRACT. The particulate matter (PM) from the atmosphere is able to penetrate in the respiratory system presenting several health risks such as acute respiratory items, allergic issues, and chronic risks such as silicosis and asthma. PM from atmosphere is classified by diameter as PM10 -particles with aerodynamic diameter up to 10 µm, PM2.5 -particles with aerodynamic diameter up to 2.5 µm, and PM1 -particles with aerodynamic diameter up to 1 µm. The first major PM source is the street dust (SD) which induces mineral fraction into the atmosphere such as: quartz, kaolinite, calcite, muscovite, and goethite. The second PM source is the pollen from several species like Tilia Cordata, Sambucus Nigra, Jasminus Communis, Rosaceae Family, Lilium Candidum, and Brassica Rapa, during later spring and early summer. Elements from both sources were found in PM samples collected from atmosphere: sedimentary particles, PM10 and PM2.5. In vivo experiments show that PM10 affects upper respiratory pathways such as nasal cavity and pharynges meanwhile PM2.5 was found in the expectoration matter from tracheal area. These studies reveal that 5 minutes of exposure at a concentration of 125 µg/m 3 conducts to formation of severe deposits on respiratory mucosa.
The aim of this paper is to assess the chemical and mineralogical composition and the leaching behavior of the electric arc furnace slags (EAFS) in order to improve their management by identifying suitable reuse options in different fields. The chemical and mineralogical composition of slag varies from one type of steel to another, from one technological stage to another and from one steel plant to another. In order to minimize the slag quantities disposed in the slag dumps one has first to characterize the generated slags for each technological stage of the steelmaking process. The chemical composition, as percentages, of the compounds identified in melting, refining and deoxidizing slags characterized varies between: (27-50%) for calcium oxide (CaO), (15-25%) for silicon dioxide (SiO2), (8-30%) for total iron (Fe tot.), (3-10%) for manganese oxide (MnO), (5-8%) for magnesia oxide (MgO), (5-6%) for alumina (Al2O3) and (0.1-0.4%) for phosphorus pentoxide (P2O5). As a result of the mineralogical characterization of the slag samples there were identified the following mineralogical compounds: jacobsite (MnFe2O4), wustite (FeO), magnetite (Fe3O4), hematite (Fe2O3), grossular ((Ca2.869Fe0.131)(Al1.89Fe0.11)(SiO4)3), andradite (Ca3Fe2(SiO4)3), pyrope ((Mg0.92Fe0.05Ca0.03)3Al2SiO4), akermanite (Ca2Mg(Si2O7)), fayalite manganoan magnesian (Mg.075Fe1.741Mn.123SiO4), srebrodolskite (CaFeO4), grossularite (Ca3Al2(SiO4)3), gehlenite (Ca2Al2SiO7), merwinite (Ca3Mg(SiO4)2), Fe-ringwoodite (Fe2(SiO4)), monticellite (CaMg(SiO4)) and fayalite-tephorite (FeMn(SiO4)). The slags can be used in different fields without any risk of harmful impact on the environment due to heavy metal leaching. The whole usage of slag would result in the conservation of natural resources and the elimination of the environmental problems with final disposal.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.