Physico-Chemical Characterization of Steel Slag. Study of its Behavior under Simulated Environmental Conditions

Abstract

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.

Column Studies for the Simultaneous Removal of Phenol, Ammonia and Thiocyanate by the Adsorption with Steel Slag

“…According to the IUPAC, the material can be classified as mesoporous material. This is also confirmed by the studies done elsewhere [35]. Figure 3 shows that increase in bed height of the slag in the column increase the breakthrough time but increase in flow of wastewater in the column reduces the breakthrough time.…”

Effects of surface Fe(III) oxides in a steel slag on the formation of humic-like dark-colored polymers by the polycondensation of humic precursors

“…The compositions of inorganic elements for the untreated and treated slag samples are summarized in [27]. Because the steel slag used in the present study was neutralized with CO 2 , Ca was mainly present in the form of calcite (CaCO 3 ), suggesting that silicates or silicon are present as non-crystalline forms.…”

Chemical and Mineralogical Characterization of Ghanaian Foundry Slags

“…(CaO+MgO):SiO 2 ≥ 1). In practice, for technological reasons, the Al 2 O 3 :Fe 2 O 3 ratio (must be < 1), or so called hydraulic properties, expressed by the relationship (CaO+MgO+Al 2 O 3 )/SiO 2 (must be > 1) should also be known [7]. It is interesting to know that, even though the chemical composition of slags has complicated structures, they are usually expressed as if these compounds existed separately within the material.…”

“…There are different types of ferrous slags, each one named from the process of which they are generated: blast furnace slag (BF) also called iron slag, basic oxygen furnace slag (BOF), electric arc furnace slag (EAF) and ladle furnace slag (LF) also called refining slag. Slag types investigated in this work are cupola furnace (CF) slag and induction furnace (IF) slags [7].…”

“…EAF has however, found increased use as recycled aggregate in road construction [12]. Steel slag having high content of CaO but low levels of phosphorus and sulfur are reused as fluxing material in steel making process to replace limestone [7]. Steel slags are also being used in areas such as road construction, fertilizers and soil conditioners, and for metal recoveries.…”