Effect of MgO and CaO/SiO2 on the immobilization of chromium in synthetic slags

Cabrera-Real, Hugo; Romero‐Serrano, Antonio; Zeifert, Beatriz; Hernández-Ramírez, Aurelio; Hallen‐Lopez, Manuel; Cruz-Ramírez, Alejandro

doi:10.1007/s10163-012-0072-y

Cited by 60 publications

(35 citation statements)

References 6 publications

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“…There are four major ferrous EAF slag minerals that usually contain Cr: spinels (AB 2 O 4 ), merwinite (Ca 3 MgSi 2 O 8 ), brownmillerite (Ca 2 (Al,Fe) 2 O 5 ), and magnesiowüstite (MeO) . Depending on which elements the spinels consist of they can either stable or unstable Spinels become more soluble as the calcium content increases . The dissolution of merwinite has been studied by Engström et al, who showed that merwinite is soluble, especially in acidic and neutral pH.…”

Section: Introductionmentioning

confidence: 99%

“…[17] Depending on which elements the spinels consist of they can either stable [10] or unstable Spinels become more soluble as the calcium content increases. [19] The dissolution of merwinite has been studied by Engström et al, [14] who showed that merwinite is soluble, especially in acidic and neutral pH. Only two phases are left to be investigated; magnesiowü stite and brownmillerite.…”

Section: Introductionmentioning

confidence: 99%

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Effect of FeO/MgO Ratio on Dissolution and Leaching of Magnesiowüstite

Strandkvist

Sandström

Engström

2017

steel research int.

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If slag is to be used as construction material, the leaching of some elements, such as chromium must be limited. The leaching of slag depends on the leaching properties of the minerals in the slag. However, the leaching/dissolution properties of individual slag minerals are usually not studied. One common slag mineral that can contribute to the leaching of chromium is magnesiowüstite. The object of this study is to determine whether magnesiowüstite can be modified to avoid chromium leaching. Magnesiowüstite samples with different FeO/MgO ratios with and without chromium content are manufactured. The dissolution is evaluated at pH 7 and 10 using the magnesiowüstite samples without chromium, at size fraction 20–38 μm, by measuring the acid consumption required to maintain constant pH level. The magnesiowüstite samples with chromium content are leached at pH 10; the leachate is analyzed for chromium. The results are unanimous, with increasing FeO content the dissolution of magnesiowüstite and leaching of chromium decrease. At pH 10 the magnesiowüstite, with ≥60 wt% FeO show no sign of dissolution and no chromium leaching could be detected with ≥70 wt% FeO. The results prove that the FeO content can stabilize magnesiowüstite and, thereby, prevent chromium leaching.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of FeO/MgO Ratio on Dissolution and Leaching of Magnesiowüstite

Strandkvist

Sandström

Engström

2017

steel research int.

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“…Adding spinel-forming agents, such as MgO and Al 2 O 3 , may promote Cr-containing spinel crystallization. 14,15) After such a slag composition adjustment, the grain size of the spinel mainly depends on the temperature to which it is exposed and the duration of the exposure. 16) Controlling the cooling conditions can affect the mineral transformation of slag and the growth behavior of spinel, although it is dif-ficult to realize the growth of spinel to a grain size above 30 μm.…”

Section: Shear-force Based Stainless Steel Slag Modification For Chromentioning

confidence: 99%

Shear-Force Based Stainless Steel Slag Modification for Chromium Immobilization

et al. 2019

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“…Various studies on the influence of the chemical and mineralogical composition on the release of heavy metals from steel slags as well as on surface reactions controlling the leaching behavior of slags are available (e.g., Aldrian [1][2][3][4][5][6][7][8]). However, conclusions drawn from these studies are not always applicable for all elements and all slag systems.…”

Section: Introductionmentioning

confidence: 99%

“…The potential of tailoring mechanical properties and leaching behavior of steel slags by adjusting the slag forming components and process parameters (cooling rate) is described, for example, by Cabrera-Real et al (2012) and Tossavainen et al (2007) [5,19]. The influence of quartz addition on the phase stability with respect to the hydraulic behavior was investigated by Mombelli et al (2014) [20].…”

Section: Introductionmentioning

confidence: 99%

Tailoring the FeO/SiO2 Ratio in Electric Arc Furnace Slags to Minimize the Leaching of Vanadium and Chromium

et al. 2020

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Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO 2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO 2 ratio. Prior to the melting experiments, the optimum FeO/SiO 2 ratio was calculated via FactSage TM . In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO 2 ) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO 2 ratio influences the mineralogy and the leaching behavior.

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Effect of MgO and CaO/SiO2 on the immobilization of chromium in synthetic slags

Cited by 60 publications

References 6 publications

Effect of FeO/MgO Ratio on Dissolution and Leaching of Magnesiowüstite

Effect of FeO/MgO Ratio on Dissolution and Leaching of Magnesiowüstite

Shear-Force Based Stainless Steel Slag Modification for Chromium Immobilization

Tailoring the FeO/SiO2 Ratio in Electric Arc Furnace Slags to Minimize the Leaching of Vanadium and Chromium

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