Isolation or corrosion of microporous alumina in contact with various CaO-Al 2 O 3 -SiO 2 slags

Fu, Lvping; Huang, Ao; Lian, Pengfei; Gu, Huazhi

doi:10.1016/j.corsci.2017.01.018

Cited by 60 publications

(31 citation statements)

References 19 publications

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“…The total O content (T[O]), including the dissolved O in the molten steel ([O]) and O in oxide inclusions (i[O]), is often used to estimate the quality and cleanliness of steel . The T[O] in the steels placed in contact with various refractories after different smelting times are shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…This is because the second phase is more easily supersaturated and precipitates and ripens at higher rates as the pore size of the lightweight alumina aggregate decreases; thus, a continuous isolation layer consisting of CaAl 12 O 19 (CA 6 ) and CaAl 4 O 7 (CA 2 ) forms around the alumina aggregate to prevent further slag corrosion and penetration . Moreover, when in contact with low‐viscosity molten slags, the uptake of molten slag in the pores is very fast; therefore, a smaller critical pore size is required to form a continuous isolation layer …”

Section: Introductionmentioning

confidence: 99%

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Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Zou

Huang

et al. 2018

J Am Ceram Soc

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Lightweight refractory linings for industrial furnaces have become important subjects of development in high‐temperature industries. The reaction mechanism between a lightweight microporous alumina‐based refractory material and molten steel was investigated in this study. The main mechanism of refractory damage was structural spalling, caused by steel penetrating the pores. The many micropores in lightweight microporous alumina have high specific surface area and reactivity, inducing the formation of FeO–Fe2O3–Al2O3 phases. This impeded the further penetration of molten steel and the direct dissolution of refractory oxides, promoting greater resistance to molten steel than that shown by common tabular alumina‐based refractories, in which Fe does not react and steel penetration through the pores cannot be retarded.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Zou

Huang

et al. 2018

J Am Ceram Soc

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“…When slag penetrates the grain boundary, a certain penetration depth is formed. Meanwhile, the dissolution process of magnesia grains into slag is dominated by diffusion, and the dissolution rate can be calculated as follows:

V_{normalS} = 360 \frac{ρ_{sl}}{ρ_{s}} β (C_{normalS} - C_{0})

where V S is the dissolution rate, mm/s; ρ sl is the density of slag, g/cm 3 ; ρ s is the density of magnesia, g/cm 3 ; β is the mass transfer coefficient, mm/s; C S is the saturated mass fraction of MgO in slag, wt%; and C 0 is the initial mass fraction of MgO in slag, wt%.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Corrosion modeling of magnesia aggregates in contact with CaO–MgO–SiO₂ slags

et al. 2019

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Ladle refining is an efficient process for improvement of quality of steel on secondary metallurgy under harsh conditions. Magnesia refractories with high purity are important raw materials for ladle lining in high‐quality steel production. However, the penetration by CaO–MgO–SiO2 slags damages magnesia refractories, which considerably limits their service life. Abundant grain boundaries in magnesia create channels for slag penetration and lead to the destruction of the structure. The effect of the microstructure on the slag corrosion behavior of magnesia aggregates requires further systematic investigation. In this study, a corrosion model was established to describe the slag penetration process of magnesia aggregates. The effects of the grain‐boundary size and slag CaO/SiO2 mass ratio (C/S ratio) on slag penetration were investigated, and the possibility of the microstructure optimization of magnesia aggregates was discussed. The results indicated that magnesia aggregates exhibited excellent slag resistance for slag with a C/S ratio above 1.5 or even 2.0. When the slag C/S ratio was lower than 1.5, the dissolution rate of magnesia decreased more rapidly with the increase in the slag C/S ratio. In addition, the much smaller grain‐boundary size increased the slag penetration resistance by promoting the formation of a dense isolation layer and inhibiting further penetration processes. The calculation results agreed well with the experimental results, suggesting that the corrosion model is promising for predicting slag corrosion.

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“…Through the carbothermal reduction of MgO, Yin et al fabricated lightweight corundum‐spinel refractory material with an apparent porosity of approximately 30% . Based on the characteristic of superplasticity, lightweight Al 2 O 3 ‐MgAl 2 O 4 refractory with a closed porosity of 16% and pore size of 10 μm was obtained by Yuan et al Fu et al fabricated lightweight alumina containing microscale intracrystalline pores and investigated its slag corrosion behavior . They pointed out that an isolation layer formed on the surface of the lightweight alumina during a slag corrosion test, converting the direct dissolution of lightweight alumina into indirect dissolution, meaning that the lightweight alumina exhibited guaranteed slag corrosion .…”

Section: Introductionmentioning

confidence: 99%

“…They pointed out that an isolation layer formed on the surface of the lightweight alumina during a slag corrosion test, converting the direct dissolution of lightweight alumina into indirect dissolution, meaning that the lightweight alumina exhibited guaranteed slag corrosion . However, further analysis revealed that the formation of a continuous isolation layer does not always occur in situ when lightweight alumina reacts with different molten slags . When reacting with molten slags with low viscosity, lightweight materials with nanoscale pores exhibit guaranteed slag corrosion.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of lightweight alumina with nanoscale intracrystalline pores

Huang

et al. 2019

J Am Ceram Soc

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In this study, lightweight alumina containing nanoscale intracrystalline pores was fabricated by introducing zirconia sol and alumina sol into α‐Al2O3 micropowder. The effects of zirconia sol on the sintering behavior of lightweight alumina were also investigated. With the introduction of zirconia sol, the grain growth and phase transformation of nano‐alumina are delayed. Therefore, the structure of the nanoscale pores between nanoparticles can be stabilized during heat treatment, and numerous nanoscale intracrystalline pores with diameters in the range of 50‐300 nm are trapped in the alumina grains. Because of the existence of these nanoscale intracrystalline pores, the thermal conductivity of lightweight alumina decreases significantly. Lightweight alumina with the addition of 0.75 wt% zirconia sol exhibits 31% lower thermal conductivity compared to alumina without zirconia sol.

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Isolation or corrosion of microporous alumina in contact with various CaO-Al 2 O 3 -SiO 2 slags

Cited by 60 publications

References 19 publications

Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Corrosion modeling of magnesia aggregates in contact with CaO–MgO–SiO₂ slags

Fabrication of lightweight alumina with nanoscale intracrystalline pores

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Isolation or corrosion of microporous alumina in contact with various CaO-Al 2 O 3 -SiO 2 slags

Cited by 60 publications

References 19 publications

Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Corrosion mechanism of lightweight microporous alumina‐based refractory by molten steel

Corrosion modeling of magnesia aggregates in contact with CaO–MgO–SiO2 slags

Fabrication of lightweight alumina with nanoscale intracrystalline pores

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Corrosion modeling of magnesia aggregates in contact with CaO–MgO–SiO₂ slags