The chemical and mineralogical composition of steel slag produced in two ArcelorMittal steel plants located in the North of Spain, as well as the study of the influence of simulated environmental conditions on the properties of the slag stored in disposal areas, was carried out by elemental chemical analysis, XRF, X-ray diffraction, thermal analysis, and scanning electron microscopy with EDS analyzer. Spectroscopic characterization of the slag was also performed by using FTIR spectroscopy. Due to the potential uses of the slag as low cost adsorbent for water treatment and pollutants removal, its detailed textural characterization was carried out by nitrogen adsorption-desorption at 77 K and mercury intrusion porosimetry. The results show that the slag is a crystalline heterogeneous material whose main components are iron oxides, calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate), elemental iron, and quartz. The slags are porous materials with specific surface area of 11 m(2)g(-1), containing both mesopores and macropores. Slag exposure to simulated environmental conditions lead to the formation of carbonate phases. Carbonation reduces the leaching of alkaline earth elements as well as the release of the harmful trace elements Cr (VI) and V. Steel slags with high contents of portlandite and calcium silicates are potential raw materials for CO(2) long-term storage.
A novel metastable layered titanium phosphate has been synthesized by the treatment of layered titanates (Na2Ti3O7 and Na4Ti9O20) with 1–2 M phosphoric acid solution at 120–150 °C. Based on the data of 31P MAS NMR and IR spectroscopy, x-ray powder diffraction, and thermal and elemental analysis, the formula Ti2O3(H2PO4)2 · 2H2O was assigned to the novel compound. The layered nature of the compound was confirmed from n-alkylamine intercalation and the ion exchange behavior toward alkali, alkaline earth, and some transition metal ions.
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