The role of pH on leaching of heavy metals and chlorides from electric arc furnace dust in cement-based mortars

Ledesma, Enrique; Lozano-Lunar, Angélica; Ayuso, Jesús; Galvín, Adela P.; Fernández, José Antonio Fernández; Jiménez, José Ramón

doi:10.1016/j.conbuildmat.2018.06.175

Cited by 40 publications

(22 citation statements)

References 41 publications

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“…These facts were in accordance with Figure 11 (XRD patterns), in which the compressive strength behaviour of mortars could be attributed to the formation of the Portlandite phase [ 15 , 18 , 20 ], since this phase only appeared in mortars with good mechanical properties (RM, EAFD25, and EAFD25_H2) and was not present in EAFD25_H1 or EAFD25_H3. These results were in agreement with those in Ledesma et al [ 15 , 18 ] and Lozano-Lunar et al [ 20 ] who showed that Portlandite (Ca(OH) 2 ) was formed due to the extension of the Portland cement reaction. Hydrotalcite, due to its acid-base characteristics, to a greater or lesser extent, inhibits the hydration reaction of cement, which translates into a minor amount or absence of Portlandite (Ca(OH) 2 ).…”

Section: Resultssupporting

confidence: 89%

“…The conventional immobilisation mortars EAFD50, EAFD75, and EAFD100 exhibited a sudden drop in compressive strength with values of 1.18, 1.71, and 1.81, respectively, with the increase in heavy metal content. Heavy metals influence cement hydration and, therefore, the acquisition of compressive strength [ 15 , 18 , 55 ].…”

Section: Resultsmentioning

confidence: 99%

“…Issa et al [ 1 ] observed liberation of Zn using cement as a solid matrix. Ledesma et al [ 15 ] reduced EAFD polluting potential through S/S treatment with mortars using Portland cement, a limestone filler and siliceous natural sand. EAFD was incorporated in a ratio of 2:1 by weight (mortar−EAFD).…”

Section: Introductionmentioning

confidence: 99%

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A Double Barrier Technique with Hydrotalcites for Pb Immobilisation from Electric Arc Furnace Dust

et al. 2019

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A new line of mortars incorporating hydrotalcites was developed. This research article shows the results of a study of a double barrier technique (DBT) for Pb immobilisation from electric arc furnace dust (EAFD) in mortars with the addition of three different hydrotalcites (H1, H2, and H3). Electric arc furnace dust (EAFD) is a hazardous waste due to its heavy metal leachability. The aim was to obtain a mortar in which, due to its chemical composition, heavy metal leaching satisfied environmental criteria. Previously, a physical and chemical characterisation of mortar material components was carried out. The leaching behaviour of Pb from EAFD in double barrier (DB) mortars with different hydrotalcites was analysed for compressive strength to determine treatment effectiveness. DB mortars could be considered monoliths because their compressive strengths were higher than 1 MPa but exhibited a decrease due to hydrotalcite incorporation. The mortar EAFD25_H2 (with ethylenediaminetetraacetate (EDTA) in the interlayer of the hydrotalcite) showed one minor reduction in compressive strength with respect to the reference mortar because formation of Portlandite was observed, which is a characteristic of cement hydration. The conventional immobilisation mortar (EAFD25) did not achieve Pb immobilisation. However, DB mortars with dimercaptosuccinate (DMSA) in the interlayer of the hydrotalcite reduced Pb release by ~50%, from 20.29 mg kg−1 (EAFD25) to 9.88 mg kg−1 (EAFD25_H3). In addition, EAFD25_H3 included the lowest hydrotalcite content, thereby improving the immobilisation ratio. The results of this study contribute to better Pb immobilisation, thus satisfying environmental criteria.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

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A Double Barrier Technique with Hydrotalcites for Pb Immobilisation from Electric Arc Furnace Dust

et al. 2019

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“…The concentrations of four metals, i.e., Cu, Pb, Cr, and Ba in the GFFA-containing brick could be dissolved in the leachate, at higher concentrations than those observed for the FBFA-containing brick. However, Zn concentration in the GFFA-containing brick was lower than that of the FBFA-containing brick, probably due to the acetic acid buffer system [29]. Fortunately, the amounts of all metals in the leachates of both bricks were lower than those accepted according to GB16889-2008, when the amount of GFFA was lower than 40% in total.…”

Section: Leaching Heavy Metal Concentrations Of the Two Types New Devmentioning

confidence: 77%

Microstructure and Strength of Alkali-Activated Bricks Containing Municipal Solid Waste Incineration (MSWI) Fly Ash Developed as Construction Materials

Zhao

Qiu

et al. 2019

Sustainability

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Alkali-activated materials (AAM) are widely applied in the field of building materials and civil engineering to substitute cement materials. This study used two types of municipal solid waste incineration fly ash (MSWI-FA): grate-firing fly ash (GFFA) and fluidized bed fly ash (FBFA) as brick raw materials. Various weight ratio of 20%, 30%, and 40% GFFA and FBFA were added to coal fly ash (CFA), GGBFs (Ground Granulated Blast-Furnace Slag), and an alkali-activating reagent to produce alkali-activated bricks. Microstructure and crystalline phase composition were observed to analyze their compressive strength, and a leaching test was used to prove the material’s safety for the environment. It can be seen from the results of this study that the alkali-activated bricks containing FBFA had higher compressive strength than those containing GFFA in the same amount. Considering the engineering properties, the alkali-activated bricks containing FBFA are more suitable to be used as building materials. The difference in the compressive strength resulted from the large amount of calcium compounds and chloride salts present in the GFFA. From SEM analysis, it was observed that there was a large number of pores in the microstructure. It was also found from the results of XRD that the bricks containing GFFA contained a large amount of chloride salt. From the results of the two leaching tests, it was found that the amounts of six heavy metals detected in the leachates of the bricks in this study met the corresponding regulation standards. This described MSWI-FA is suitable for use as alkali-activated material, and its products have potential to be commercially used in the future.

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“…Furthermore, Spain is the third-highest steel producing country in the European Union [15]. More than 75% of its steel is produced through scrap recycling [16]. The scrap is melted in an electric arc furnace at temperatures above 1600 • C, and in this process occurs the volatilization of elements such as iron, zinc and lead, which react with oxygen and generate waste in the form of dust.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Study of Recycled Aggregate Mortar for Electric Arc Furnace Dust Encapsulation

et al. 2021

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This article shows the preliminary results of a study carried out to determine the technical feasibility of encapsulating a high percentage of EAFD in cement-based mortars manufactured with the fine fraction of recycled concrete aggregates (RCA). Two families of mortars, with natural aggregate as a reference and with RCA, were studied. An incorporation rate by weight of two parts mortar to one part EAFD was tested. The mechanical strengths (compressive strength and tensile strength) before and after immersion in water, the rate of delitescence and the leaching behavior were studied. Mortars made with RCA showed similar mechanical strengths to the reference mortars made with natural aggregates; however, the incorporation of EAFD decreased the mechanical strengths. Encapsulation considerably reduced the leaching of heavy metals, although the Pb concentration remained above the hazardous waste limit. With this preliminary study, two wastes are managed together, and the results have shown that the use of RCA instead of natural aggregate is a viable alternative since it does not significantly impair the mechanical or leaching properties of the cement-based matrices used to encapsulate EAFD.

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The role of pH on leaching of heavy metals and chlorides from electric arc furnace dust in cement-based mortars

Cited by 40 publications

References 41 publications

A Double Barrier Technique with Hydrotalcites for Pb Immobilisation from Electric Arc Furnace Dust

A Double Barrier Technique with Hydrotalcites for Pb Immobilisation from Electric Arc Furnace Dust

Microstructure and Strength of Alkali-Activated Bricks Containing Municipal Solid Waste Incineration (MSWI) Fly Ash Developed as Construction Materials

Preliminary Study of Recycled Aggregate Mortar for Electric Arc Furnace Dust Encapsulation

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