Bonding phase formation in eco-friendly periclase−spinel−Al bricks used in RH degassing process

Guo, Zongqi; Lei, Zhongxing; Ma, Ying; Huang, Zhiming; Dang, Xiaomei; Xu, Zhao‐Dong

doi:10.1016/j.jeurceramsoc.2023.01.002

Cited by 6 publications

(8 citation statements)

References 13 publications

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“…The magnesia particles swimming in the liquid are observed at the hot face. In previous investigation on the used brick, 18 there was only 700 μm deep oxidation zone found at the hot face and no obvious slag penetration was observed. It is believed that interwoven‐whisker‐network bond of periclase–spinel–Al brick has advantage to inhibit slag penetration.…”

Section: Resultsmentioning

confidence: 77%

“…Residual periclase–spinel–Al brick served in the snorkel had high concentration of thin‐whisker network (most whiskers with 1−2 μm in diameter and 10−35 μm in length), after 101 heats of service time. Residual periclase–spinel–Al brick served in the lower vessel showed high concentration of coarse‐whisker network (most whiskers with 4−5 μm in diameter and 20−35 μm in length), after 227 heats of service time 18 . It is believed that the whisker network bond is weaker within the samples tested in wedge splitting test than the residual bricks from RH degassers, in terms of the concentration of whisker network and size.…”

Section: Discussionmentioning

confidence: 95%

“…Residual periclase-spinel-Al brick served in the lower vessel showed high concentration of coarse-whisker network (most whiskers with 4−5 μm in diameter and 20−35 μm in length), after 227 heats of service time. 18 It is believed that the whisker network bond is weaker within the samples tested in wedge splitting test than the residual bricks from RH degassers, in terms of the concentration of whisker network and size. Their mechanical properties at high temperature, corrosion resistance and fracture behavior can be further improved after the formation of highconcentration, whisker-network bond acquired in the use of RH degasser.…”

Section: Bonding Formation Process In Periclase-spinel-al Brickmentioning

confidence: 99%

“…15,16 Both studies on periclase-spinel-Al bricks heated in labs and used in RH degassers had the findings of a whisker interwoven network all over the matrix. 17,18 Magnesia-chrome brick, magnesia-spinel brick and unburnt periclase-spinel-Al brick are all being used in RH degassers. It would be interesting to understand what plays a critical role in using of those materials and why an unburnt brick becomes the best potential alternative to magnesia-chrome brick.…”

Section: Introductionmentioning

confidence: 99%

“…Surprisedly, an unburnt periclase–spinel–Al brick appeared for years, achieving optimistic performance in various RH degassers and demonstrating outstanding properties 15,16 . Both studies on periclase–spinel–Al bricks heated in labs and used in RH degassers had the findings of a whisker interwoven network all over the matrix 17,18 …”

Section: Introductionmentioning

confidence: 99%

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Three bond modes of basic refractories used for Ruhrstahl Heraeus degassing process

et al. 2023

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Magnesia-spinel brick and unburnt periclase-spinel-Al brick are being employed as a substitution of traditional magnesia-chrome brick in the chromium-free campaign of lining materials in Ruhrstahl Heraeus (RH) degasser. These three materials are investigated, in terms of physical properties, corrosion resistance and flexibility by wedge splitting test. Tracking their physical alterations and chemical reactions through burning or heating, three bond modes are discovered. Magnesia-chrome brick is subject to a series of phase transformation with rising temperature to yield a liquid envelop around chromite-ore particles, to further form porous rim while liquid is gradually absorbed by surrounding magnesia and eventually to precipitate secondary chromite spinel lied between magnesia particles by thoroughly dissociating chrome ore. The precipitated chromite spinel functions as the featured bond that enhances hot strength and corrosion resistance to slag, and additionally liquid coexistence improves the flexibility. The direct bond mode of magnesia particles in magnesia-spinel brick endures slag penetration by immanent character of MgO. Spinel incorporation in magnesia effectively improves thermal shock resistance. Due to minor negative value of permanent linear change after reheating, further sintering (densifying) in using at high temperature would bring a risk of loosening and open joints of magnesia-spinel lining. While used in RH degasser, unburnt periclase-spinel-Al bricks undergo a miraculous process of metallic Al melting, gaseous AlN and AlON formation, MgAlON whiskers germination combined with gaseous Mg reduced, and micron-size whisker network bond domination in their matrix. Such a whisker-network bond renders the material a successful eco-friendly alternative to magnesia-chrome refractory.

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Section: Resultsmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 95%

Section: Bonding Formation Process In Periclase-spinel-al Brickmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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