Recycling MgO–C refractories and dolomite fines as slag foaming conditioners: experimental and thermodynamic evaluations

Luz, A.P.; Vivaldini, D. O.; López, Francisco Javier; Brant, Patrick; Pandolfelli, V. C.

doi:10.1016/j.ceramint.2013.03.080

Cited by 20 publications

(5 citation statements)

References 8 publications

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“…The range composition of the slag foams is The content of Si, Ca, and Mg oxides does not differ significantly between the samples from the top and bottom of the crucible and between different carbon sources. The reason for the decrease in the MgO content in all samples can be explained by the activity of MgO with some other slag components [48,49].…”

Section: Resultsmentioning

confidence: 91%

Evaluation of Slag Foaming Behavior Using Renewable Carbon Sources in Electric Arc Furnace-Based Steel Production

et al. 2023

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The influence of different carbon sources, including anthracite, calcined petroleum coke, three samples of high-temperature coke, biochar, and a mixture of 50 wt.% biochar and 50 wt.% coke, on slag foaming behavior was studied. The slag’s composition was set to FeO-CaO-Al2O3-MgO-SiO2, and the temperature for slag foaming was 1600 °C. The effect of the carbon sources was evaluated using foaming characteristics (foam height, foam volume, relative foaming height, and gas fraction), X-ray diffraction (XRD), chemical analysis of the slag foams, Mossbauer spectroscopy, observation by scanning electron microscope (SEM), and energy-dispersive spectroscopy (EDS) mapping. Different foaming phenomena were found among conventional sources, biochar as a single source, and the mixture of coke and biochar. Biochar showed the most inferior foaming characteristics compared to the other studied carbon sources. Nevertheless, the slag foaming process was improved and showed slag foaming characteristics similar to results obtained using conventional carbon sources when the mixture of 50 wt.% coke and 50 wt.% biochar was used. The XRD analysis revealed a difference between the top and bottom of the slag foams. In almost all cases, a maghemite crystalline phase was detected at the top of the slag foams, indicating oxidation; metallic iron was found at the bottom. Furthermore, a difference in the slag foam (mixture of coke and biochar) was found in the presence of such crystalline phases as magnesium iron oxide (Fe2MgO4) and magnetite (Mg0.4Fe2.96O4). Notwithstanding the carbon source applied, a layer between the foam slag and the crucible wall was found in many samples. Based on the SEM/EDS and XRD results, it was assumed this layer consists of gehlenite (Ca2(Al(AlSi)O7) and two spinels: magnesium aluminate (MgAl2O4) and magnesium iron oxide (Fe2MgO4).

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Section: Resultsmentioning

confidence: 91%

Evaluation of Slag Foaming Behavior Using Renewable Carbon Sources in Electric Arc Furnace-Based Steel Production

et al. 2023

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“…4 Recycled MgO-C refractories are used, for example, as slag conditioners in electric arc furnaces. [5][6][7] However, the highest benefit can be achieved when they are used as secondary raw materials for the production of refractories. 4 Nakamura et al showed that MgO-C bricks containing 30% recycled material are suitable to replace low-grade MgO-C bricks from virgin material.…”

Section: Introductionmentioning

confidence: 99%

Magnesia‐carbon refractories from recycled materials

Moritz

Dudczig

Endres³

et al. 2022

Int J Ceramic Engine & Sci

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Recycling of used refractories -in particular closed-loop recycling -gains in importance because of both ecological and economic benefits, such as the conservation of natural resources, reduced landfilling, and the reduction of greenhouse gases and energy consumption. In this work, the use of a magnesia-carbon (MgO-C) recyclate for the production of MgO-C refractories is investigated. Using fused magnesia, the mentioned MgO-C recyclate, graphite, novolak, and a modified coal tar pitch, test specimens with different recyclate contents (0, 40, 65, and 82 wt%) were prepared on a laboratory scale. The apparent porosity, which is usually higher in recyclate-based refractories than in recyclate-free ones, increased by 14% from the specimens made exclusively from virgin raw materials to those made from the mixture containing 82 wt% recyclate. The dynamic Young's modulus and cold modulus of rupture decreased, but the thermal shock resistance was improved by the use of the recyclate.

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“…The state of the postmortem refractory linings determines the processing effectivity and the economy of the material recycling. The recovered materials may be used according to their quality as building materials (gravel) or as an additive to slags, also as secondary raw materials for the production of building ceramics, inorganic binding materials or some new non-shaped/refractories [3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

SPECIFICATION OF MgO-CONCENTRATE OBTAINED FROM POST MORTEM MgO-C REFRACTORY MATERIALS

Plešingerová¹

2018

Ceramics - Silikaty

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The recycling process of post mortem MgO-C (MC) materials is based on carbon removal from the crushed material. The laboratory results of the annealing of the crushed post-mortem MC bricks in a static layer, in an air atmosphere in an electric furnace are presented. The quantity and quality of the fractions size was evaluated before and after annealing. The results show that the carbon inside the grains of size 6.3-15 mm is incompletely burnt out under the given conditions. The results from annealing of the fractions size below 6.3 mm confirmed that the carbon burning out decreases the strength and density of the agglomerates, which then partially disintegrate during annealing. A mechanical load is needed for the complete disintegration of the brittle agglomerates. In addition, the results of the MgO-fractions quality evaluation are discussed, which were obtained by annealing the grit from the post-mortem MC bricks from the pilot-plant experiment in a rotary kiln in the factory Hačava, from the company INTOCAST Slovakia a.s.. The obtained fraction size of MgO possesses a suitable chemical and phase composition. However, the strength of the MgO-grains core was lower. This confirms that the post-mortem MC materials may be recycled; however, it requires waste management and the related technical equipment for the recycling processes.

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Recycling MgO–C refractories and dolomite fines as slag foaming conditioners: experimental and thermodynamic evaluations

Cited by 20 publications

References 8 publications

Evaluation of Slag Foaming Behavior Using Renewable Carbon Sources in Electric Arc Furnace-Based Steel Production

Evaluation of Slag Foaming Behavior Using Renewable Carbon Sources in Electric Arc Furnace-Based Steel Production

Magnesia‐carbon refractories from recycled materials

SPECIFICATION OF MgO-CONCENTRATE OBTAINED FROM POST MORTEM MgO-C REFRACTORY MATERIALS

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