Influence of the Recirculation of Various by-products Generated through Electric Arc Furnace Route on EAF Slag Quality

Mombelli, Davide; Quadrio, Matteo; Mapelli, Carlo; Echterhof, Thomas; Aparicio, Leixuri Fernandez; Sorger, Christoph; Griessacher, Thomas; Mudersbach, Dirk; Schüler, Susanne

doi:10.2355/isijinternational.isijint-2021-571

Cited by 3 publications

(1 citation statement)

References 25 publications

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“…This could further explain why smaller samples showed higher W leaching compared to coarser ones. As stated by Quadrio et al [16], the leaching of tungsten tends to grow linearly with the CaO content in the slag. Although, in this work, the general chemical composition of each granularity fraction was not calculated, it is possible to state that higher CaO content should be detected in smaller granularity fractions, when compared to coarser ones, due to the higher amount of Ca contained in both spinels and larnite.…”

Section: W and Mo Leachingmentioning

confidence: 74%

Manipulation of the leaching behaviour of high-alloyed steel EAF slags through the particle size modulation

Mombelli,

Dall’Osto,

Cozzo

et al. 2024

IOP Conf. Ser.: Mater. Sci. Eng.

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The safe disposal of EAF slag have become crucial due the environmental and health protection regulations. Its direct reuse is hampered by the possible release of toxic elements into the surrounding environment over time. Specifically, EAF slag from high-alloyed steel production could potentially release toxic metals (e.g., Ba, Cr, Mo and V). Currently, the assessment of leaching behaviour is carried out according to the EN 12457:2002 standard, which generically specify that the material should not be finely ground, limiting the particle size as much as possible. However, no guidance is given on reducing particle size and handling fine fractions, which could lead to manipulation of data and variability of results. In this work six different fractions (from <4 mm to <63 μm) of EAF slag from high-alloyed steel production were investigated. X-Ray Diffraction, Scanning Electron Microscopy and selective C2S dissolution were used to correlate the leaching behaviour with particle size and identify which mineral can alters the release of specific toxic elements. The pH of the water was measured immediately after filtration, and the solution was analysed by Inductively Coupled Plasma-Optical Emission Spectrometry. In addition, five mixtures were prepared using different mass fractions of the six granular fractions with the aim of unbalancing the mixtures toward coarser or finer fractions, respectively. All the mixtures were subjected to leaching under the same previous conditions and analysed to evaluate the behaviour of the different blended fractions. To investigate the predictability of the leaching behaviour of the mixtures, the experimental results were compared with the values predicted by a theoretical model calibrated using the results obtained from the leaching results of the six particle size fractions. The investigation showed that the leaching behaviour is negatively affected by the particle size reduction, mainly due to the increase of surface-to-volume ratio, which increases the dissolution rate. Similarly, the mass fraction of the main crystalline phases that regulate leaching (unstable spinels, brownmillerite and larnite) is also correlated with the change in particle size. Consequently, the leaching results for the mixtures highlighted a critical aspect contained in the European standard. Even small changes in particle size can lead to different concentrations of toxic metals in leachates, which can then be manipulated to achieve the desired result.

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Section: W and Mo Leachingmentioning

confidence: 74%

Manipulation of the leaching behaviour of high-alloyed steel EAF slags through the particle size modulation

Mombelli,

Dall’Osto,

Cozzo

et al. 2024

IOP Conf. Ser.: Mater. Sci. Eng.

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Physicochemical Properties of Air-Quenched Electric Arc Furnace Slag as Free-State Sandblasting Abrasives and Application Potential Analysis

Lin,

Zhang,

et al. 2024

ISIJ Int.

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Air-quenched electric arc furnace slag (AEAFS) is a black sphere or spheroid particle prepared by an air quenching theology using electric arc furnace steelmaking slag as raw materials, possessing the characteristics of small particle size, moderate density and high hardness Combined with the tight supply and demand of the existing abrasive market and the continuous increase in price, AEAFS is tried to be used as a free abrasive for sandblasting processing according to its physical characteristics. In order to make sure that the AEAFS meets the requirement of free abrasive blasting, it is necessary to conduct a comprehensive and in-depth analysis of its physical and chemical properties. The research shows that the AEAFS is a spherical particle with weak magnetism and particle size being mainly 2.8 mm (accounting for more than 90%). Its Vickers hardness is in the range of 600-1000HV; its compressive strength is between 20 and 465N and increases first and then decreases with particle size. The water content is more than 0.019%, except that the particle size is less than 0.5mm. All the others meet the requirements of ISO-11126-6: 2018 standard. The content of f-CaO is between 1.122% and 1.612% increasing with the particle size, AEAFS has good chemical stability and weak acid resistance. In summary, AEAFS meets the performance requirements of the medium used in the sandblasting process and is a potential alternative product for sandblasting abrasives.

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Utilization of Renewable Carbon in Electric Arc Furnace-Based Steel Production: Comparative Evaluation of Properties of Conventional and Non-Conventional Carbon-Bearing Sources

Kieush

Schenk

Koveria

et al. 2023

Metals

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Conventional (anthracite, calcined petroleum coke, and coke) and non-conventional (biochar, and biocokes (3 wt.% torrefied wood, and 3 wt.% petroleum coke + 3 wt.% charcoal)) carbon-bearing sources have been studied for their use in electric arc furnace (EAF)-based steel production. Commonly, for the use of carbon sources in EAFs, one of the important properties is the content of fixed carbon, the release of volatiles as well as the elemental composition of inorganics. The properties of six carbon sources were analyzed by determining the proximate analysis, X-ray fluorescence analysis (XRF), coke reactivity index (CRI), and strength after reaction with CO2 (CSR), Brunauer–Emmett–Teller (BET) specific surface area and Barrett–Joyner–Halenda (BJH) pore size and volume analysis, ash chemical analysis, optical and scanning microscopy, Raman spectroscopy and X-ray diffraction (XRD) analysis. The results indicate biocoke as a promising option to replace conventional carbon-bearing sources. In the sample set, the fixed carbon, volatiles, and ash content of the biocokes were similar despite the total difference in additives. Additionally, the use of additives did not significantly affect the biocoke reactivity indices, but slightly decreased the strength after the reaction with CO2. Carbon-bearing sources have been characterized in terms of their structural properties. XRD analysis revealed that the amount of disordered carbon increased in the order: coke < calcined petroleum coke ~ biocoke (3 wt.% torrefied wood) < biocoke (3 wt.% petroleum coke + 3 wt.% charcoal) < biochar. The results obtained on the physical, chemical, and structural properties of carbon sources are the basis for further research on the behavior of slag foaming.

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Influence of the Recirculation of Various by-products Generated through Electric Arc Furnace Route on EAF Slag Quality

Cited by 3 publications

References 25 publications

Manipulation of the leaching behaviour of high-alloyed steel EAF slags through the particle size modulation

Manipulation of the leaching behaviour of high-alloyed steel EAF slags through the particle size modulation

Physicochemical Properties of Air-Quenched Electric Arc Furnace Slag as Free-State Sandblasting Abrasives and Application Potential Analysis

Utilization of Renewable Carbon in Electric Arc Furnace-Based Steel Production: Comparative Evaluation of Properties of Conventional and Non-Conventional Carbon-Bearing Sources

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