Minimizing Chromium Leaching from Low-Alloy Electric Arc Furnace (EAF) Slag by Adjusting the Basicity and Cooling Rate to Control Brownmillerite Formation

Strandkvist, Ida; Pålsson, Kjell; Andersson, Anton; Olofsson, Jenny; Lennartsson, Andreas; Samuelsson, Caisa; Engström, Fredrik

doi:10.3390/app10010035

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…Spinels ((Mg, Al, Fe, Cr)2O4), larnite, periclase, and brownmillerite are minerals The mineral phases identified are in line with the mineral phases reported in the literature. Spinels ((Mg, Al, Fe, Cr) 2 O 4 ), larnite, periclase, and brownmillerite are minerals commonly found in EAF C slag [36][37][38][39]. In ladle slag dicalcium silicate (γ-C2S), larnite, mayenite and tricalcium aluminate are more frequently observed [38,[40][41][42].…”

Section: Mineralogical Characterizationmentioning

confidence: 99%

Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap

Loncnar

Mladenovič

Serjun

et al. 2022

Toxics

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Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composition. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag.

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Section: Mineralogical Characterizationmentioning

confidence: 99%

Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap

Loncnar

Mladenovič

Serjun

et al. 2022

Toxics

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show abstract

“…Mombelli et al discussed the influence of microstructure on heavy metal leaching characteristics in electric arc furnace slag (Mombelli et al, 2016b), suggesting phases such as spinel and gehlenite suppress leaching of Ba, V and Cr from slag, while larnite (β-Ca2SiO4) is more prone to leaching metals. The method by which slag is cooled can also manipulate the mineralogy of the final product, and thus the leaching behavior (Strandkvist et al, 2020).…”

Section: Tablementioning

confidence: 99%

The production of high value pig iron nuggets from steelmaking by-products – A thermodynamic evaluation

Stewart

Thomson

Barron

2021

Resources, Conservation and Recycling

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“…The lack of free periclase 214 , suggesting phases such as spinel and gehlenite suppress leaching of Ba, V and Cr from slag, while larnite (β-Ca2SiO4) is more prone to leaching metals. The method by which slag is cooled can also manipulate the mineralogy of the final product, and thus the leaching behaviour 215 .…”

Section: Flux Additionsmentioning

confidence: 99%

Value Generation by Recovering By-Products from Steelmaking Processes: Dezincification of Basic Oxygen Steelmaking Slurry

Stewart¹

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The production of steel through the blast furnace/basic oxygen steelmaking route generates approximately 10kg of ferrous dusts and sludges per tonne of hot metal produced. This ferrous material is readily recyclable via a sinter plant to recover iron units but is difficult to recycle when the material is contaminated with zinc. Historically, excess material has been stockpiled or landfilled which presents an environmental issue but also a commercial opportunity to recover huge volumes of ferrous material from operating and former steelmaking sites. A review of best available technology for recovery of zinc from steelmaking by-product dusts identified that the Rotary Hearth Furnace (RHF) is the most attractive commercialized option for processing of material at an integrated plant such as Tata Steel Port Talbot, but due to the relatively low value of the ferrous direct reduced iron (DRI) product is still not commercially viable. A characterization study of basic oxygen steelmaking dust from Port Talbot, Redcar and Scunthorpe steel plants in the United Kingdom was undertaken using a variety of techniques and indicated pyrometallurgical recovery would be the preferred recovery route due to the high metallization and variability of the morphology of the dusts. Benchmarking of material from Port Talbot material processed in laboratory furnace trials under conditions mimicking the RHF showed that while volatile metal removal and iron reduction performance is adequate for recycling at realistic RHF temperatures and hold times, the high sulfur and gangue content mean the produced DRI would not be valuable enough to offset production costs. A computational thermochemical study was undertaken using FactSage and identified the possibility of applying next generation RHF technology to produce high value pig iron nuggets from steelmaking by-products. This possibility was confirmed experimentally, producing pig iron nuggets from BOS dust with complete removal of zinc from the material, at feasible process conditions, by addition of SiO2 and MgO fluxes. Alternative reductants for the RHF were also explored, specifically adapting the RHF process to utilize the enormous volume of plastic waste generated from facemasks in the wake of the COVID-19 pandemic. The addition of facemask plastic to a low-volatile coal was found to increase its CO2 gasification reactivity, which has associated process benefits for direct reduction.

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Minimizing Chromium Leaching from Low-Alloy Electric Arc Furnace (EAF) Slag by Adjusting the Basicity and Cooling Rate to Control Brownmillerite Formation

Cited by 6 publications

References 18 publications

Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap

Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap

The production of high value pig iron nuggets from steelmaking by-products – A thermodynamic evaluation

Value Generation by Recovering By-Products from Steelmaking Processes: Dezincification of Basic Oxygen Steelmaking Slurry

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