Alkali activation of electric arc furnace slag: Mechanical properties and micro analyzes

Öztürk, Murat; Bankır, Muzeyyen Balcıkanlı; Bölükbaşı, Ömer Saltuk; Sevim, Umur Korkut

doi:10.1016/j.jobe.2018.10.005

Cited by 51 publications

(21 citation statements)

References 22 publications

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“…These low values go along with those typical of non-structural materials, such as brick, tiles and foamed panels for thermal insulation. Concerning dense materials, we can compare our results with those reported by Ozturk et al (Ozturk et al, 2019) who studied activation of electric arc furnace slag with the mixture of sodium hydroxide and sodium silicate. The best-performance resulted mortar specimen reached compressive strength of 22.0 MPa.…”

Section: Alkali Activation and Properties Of The Final Consolidated Materialssupporting

confidence: 69%

Antibacterial Properties and Cytotoxicity of 100% Waste Derived Alkali Activated Materials: Slags and Stone Wool-Based Binders

et al. 2021

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In this study we compare the leaching behavior and the antibacterial and cytotoxic properties of 100% slag or stone wool derived alkali activated materials. The antibacterial activity was measured as the inhibiting capacity against two Gram-negative bacterial strains, Escherichia coli and Pseudomonas aeruginosa and one Gram-positive bacterial strain: Enterococcus faecalis. The cytotoxicity properties were tested on mouse embryonic fibroblast NIH-3T3 cell-line. It was proved that the high quality of the 3D aluminosilicate network of the consolidated materials obtained from powders of CaO or MgO-rich slags or stone wool, opportunely activated with NaO and/or Na-silicate, was capable of stabilizing heavy metal cations. The concentrations of leachate heavy cations were lower than the European law limit when tested in water. The effect of additives in the composites, basal fibers or nanocellulose, did not reduce the chemical stability and slightly influenced the compressive strength. Weight loss in water increased by 20% with basalt fibers addition, while it remained almost constant when nanocellulose was added. All the consolidated materials, cement-like in appearance, exhibited limited antibacterial properties (viability from 50 to 80% depending on the bacterial colony and the amount of sample) and absence of cytotoxicity, envisaging good acceptance from part of the final consumer and zero ecological impact. CaO-rich formulations can replace ordinary Portland cement (showing bacterial viability at 100%) with a certain capability for preventing the reproduction of the E. coli and S. aureus bacteria with health and environmental protection results.

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Section: Alkali Activation and Properties Of The Final Consolidated Materialssupporting

confidence: 69%

Antibacterial Properties and Cytotoxicity of 100% Waste Derived Alkali Activated Materials: Slags and Stone Wool-Based Binders

et al. 2021

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“…The volume of cracks and pores is affected by the alkaline reaction and the curing conditions, where water is removed from the AAM matrix [4,5]. The distribution of particles within the matrix of all samples is similar for all samples, but some cracks and voids are visible in the sample cured at room temperature, especially around single grains (Figure 11a,b).…”

Section: Resultsmentioning

confidence: 99%

“…Alkali activation technology offers the possibility to utilize large amounts of aluminosilicate-rich secondary products such as fly ash from thermoplants [1,2,3], slag from metallurgical processes [4,5] and waste glass [6] for a useful new group of building products. Steel slag-based alkali activated materials (AAM), have a high mechanical strength, show good fire resistance and high thermal resistance at elevated temperatures, and, in the case of low density, they further exhibit low thermal conductivity [7].…”

Section: Introductionmentioning

confidence: 99%

“…Authors concluded that when the curing temperature is 40 °C and time of curing is prolonged from 6 to 12 h, the cracks occur due to evaporation of water and when the temperature is higher (80 °C), the hydratation reactions are faster resulting in the denser microstructure and therefore the mechanical strengths are increased. Also the higher amounts of silica content propagate the C-S-H gel formation which densify microstructure and therefore is one of the important factor in the strength development [5].…”

Section: Introductionmentioning

confidence: 99%

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The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

et al. 2019

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Alkali activation is studied as a potential technology to produce a group of high performance building materials from industrial residues such as metallurgical slag. Namely, slags containing aluminate and silicate form a useful solid material when activated by an alkaline solution. The alkali-activated (AA) slag-based materials are promising alternative products for civil engineering sector and industrial purposes. In the present study the locally available electric arc furnace steel slag (Slag A) and the ladle furnace basic slag (Slag R) from different metallurgical industries in Slovenia were selected for alkali activation because of promising amorphous Al/Si rich content. Different mixtures of selected precursors were prepared in the Slag A/Slag R ratios 1/0, 3/1, 1/1, 1/3 and 0/1 and further activated with potassium silicate using an activator to slag ratio of 1:2 in order to select the optimal composition with respect to their mechanical properties. Bending strength of investigated samples ranged between 4 and 18 MPa, whereas compressive strength varied between 30 and 60 MPa. The optimal mixture (Slag A/Slag R = 1/1) was further used to study strength development under the influence of different curing temperatures at room temperature (R. T.), and in a heat-chamber at 50, 70 and 90 °C, and the effects of curing time for 1, 3, 7 and 28 days was furthermore studied. The influence of curing time at room temperature on the mechanical strength at an early age was found to be nearly linear. Further, it was shown that specimens cured at 70 °C for 3 days attained almost identical (bending/compressive) strength to those cured at room temperature for 28 days. Additionally, microstructure evaluation of input materials and samples cured under different conditions was performed by means of XRD, FTIR, SEM and mercury intrusion porosimetry (MIP).

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“…EAFS was also studied by Ozturk et al in an extensive study where different influential parameters (such as silicate modulus, sodium concentration, relative humidity, curing temperature and curing time) on an alkali-activation process were varied. The best performance was shown in the mortar specimen reaching the compressive and flexural strengths of 22.0 and 4.2 MPa, respectively [ 8 ]. In another study, GGBFS-based alkali-activated samples were exposed to heat curing, and the mechanism and microstructure of the alkali-activation process was investigated [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Alkali Activation of Metallurgical Slags: Reactivity, Chemical Behavior, and Environmental Assessment

et al. 2021

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Alkali-activated materials (AAMs) represent a promising alternative to conventional building materials and ceramics. Being produced in large amounts as aluminosilicate-rich secondary products, such as slags, they can be utilized for the formulation of AAMs. Slags are partially crystalline metallurgical residues produced during the high temperature separation of metallic and non-metallic materials in the steelmaking processes. In the present study, the electric arc furnace carbon or stainless steel slag (EAF) and secondary metallurgical slag such as ladle furnace basic slag (LS) were used as precursors in an alkali-activation process. EAF slag, with its amorphous fraction of about 56%, presented higher contents of soluble Si and Al species with respect to ladle slag R (35%). However, both are suitable to produce AAM. The leaching behavior shows that all the release values are below the regulation limit. All the bivalent ions (Ba, Cd, Cu, Ni, Pb, and Zn) are well immobilized in a geopolymeric matrix, while amphoteric elements, such as As and Cr, show a slight increase of release with respect to the corresponding slag in alkaline and aqueous environments. In particular, for Sb and As of AAM, release still remains below the regulation limits, while Mo presents an increase of leaching values that slightly exceeds the limit for landfill non-dangerous waste.

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Alkali activation of electric arc furnace slag: Mechanical properties and micro analyzes

Cited by 51 publications

References 22 publications

Antibacterial Properties and Cytotoxicity of 100% Waste Derived Alkali Activated Materials: Slags and Stone Wool-Based Binders

Antibacterial Properties and Cytotoxicity of 100% Waste Derived Alkali Activated Materials: Slags and Stone Wool-Based Binders

The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

Alkali Activation of Metallurgical Slags: Reactivity, Chemical Behavior, and Environmental Assessment

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