Recycling MgO-C refractory in electric arc furnaces

Conejo, Alberto N.; Lule, R.; López, Francisco Javier; Rodríguez, Rooel Campos

doi:10.1016/j.resconrec.2006.03.002

Cited by 33 publications

(15 citation statements)

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“…The significant values of iron are also highlighted because it is a refractory used in foundry pots, silicon, aluminium, and calcium, the latter possibly slag. All values are in accordance with those obtained by Conejo et al 29 The high loss to fire was mainly due to the elimination of graphite. The variation in MgO levels can be observed in proportion to the loss of ignition values of CaO.…”

Section: Resultssupporting

confidence: 92%

“…Conejo et al 29 demonstrated that there is a reduction in the presence of MgO from the new brick compared to that used. Iron oxide, contrary to the results obtained in our study, was reduced.…”

Section: Resultsmentioning

confidence: 99%

“…This was because magnetic separation was not used in our study, because the intention was to use the waste as received, that is, without any preparation method that would change its chemical composition. This also occurs with Al 2 O 3 , because in the work developed by Conejo et al 29 , we sought, despite the difficulty, to separate alumina due to its low basicity.…”

Section: Resultsmentioning

confidence: 99%

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Chemically-Bonded Magnesium Phosphate Ceramics from Magnesium Oxide-Graphite Refractory Brick Waste

et al. 2021

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In Brazil, the production of each ton of steel generates approximately 621 kg of waste and direct co-products. One of the components that generates a high amount of waste is the refractory material used in the steel process. So, in this study, the possibility of using MgO-C refractory waste from steel casting pots after their deterioration for the formation of chemically bonded phosphate ceramics was investigated. This work aims to study the recovery of industrial solid waste from MgO-C refractories by determining the processing conditions necessary to obtain magnesium phosphate ceramics. Three mean particle size of the waste and three potassium monophosphate:MgO ratio in the mixture were adopted. All mixtures showed the formation of the K-struvite phase and a strong relationship between the compressive strength and porosity properties. The highest compressive strength value obtained, 7.51 ± 0.24 MPa, is sufficient for use in several areas of engineering. It was also possible to statistically represent, using a quadratic model, the variation in porosity in relation to the phosphate content and particle size of the waste, obtaining porosities ranging from 14% to 25%. Taking into account this study used a waste, the evaluation of its environmental impact assumed an important role. The waste showed no appreciable toxicity, while some samples W3-20 showed toxicity to Allium cepa L. and Artemia salina. Considering the presented properties, the obtained material could be used as a structural block, filters, support for catalysts, and repair element for cement-based structures and roadways.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Chemically-Bonded Magnesium Phosphate Ceramics from Magnesium Oxide-Graphite Refractory Brick Waste

et al. 2021

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“…In the European Union (EU), the production of spent refractories is estimated between 1.42 and 2.66 million tons per year. Although many efforts are being conducted, these debris are an economic and environmental concern as they lack effective ways of valorizing the huge volumes generated [14][15][16]. Of these wastes, 26% are doloma and magnesia recycled refractory materials (DMRR) from the steel industry [17].…”

Section: Introductionmentioning

confidence: 99%

Stabilization of a Clay Soil Using Cementing Material from Spent Refractories and Ground-Granulated Blast Furnace Slag

et al. 2021

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Nowadays, huge amounts of refractory materials are generated around the world. The majority of them lack valorization methods. This study analyzes the ability of a doloma and two magnesia spent refractory wastes as soil stabilizers on their own, as well as when combined with Ground-Granulated Blast Furnace Slags (GGBS). These materials showed a limited ability for the soil’s plasticity modification from a plasticity index of 15.6 to a minimum of 12.7. The high pH of the additives increased the soil’s pH from 7.88 to values in the range of 10.94–11.25 before the 28 days, allowing the development of the pozzolanic reactions. Unconfined compressive strength (UCS) increased along the curing time, reaching a maximum value of 5.68 MPa after 90 days. Based on the UCS, the optimum refractory GGBS ratios oscillate between 30:70 and 50:50. The UCS values after soaking samples reduced the unsoaked results between 68.70% to 94.41%. The binders considered showed a low effect against the soil swelling and the lack of delayed expansive effects because of the MgO hydration. Finally, X Ray Diffraction (XRD) tests showed that the stabilization only slightly modified the combinations of mineralogy and the formation of Magnesium Silicate Hydrate (MSH) gels.

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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 refractory in electric arc furnaces

Cited by 33 publications

References 1 publication

Chemically-Bonded Magnesium Phosphate Ceramics from Magnesium Oxide-Graphite Refractory Brick Waste

Chemically-Bonded Magnesium Phosphate Ceramics from Magnesium Oxide-Graphite Refractory Brick Waste

Stabilization of a Clay Soil Using Cementing Material from Spent Refractories and Ground-Granulated Blast Furnace Slag

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

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