Catalytic carbon-bed sintering of CNTs/calcium aluminate cement and its effects on thermal mechanical properties of refractory castables

Lei, Changkun; Ding, Donghai; Xiao, Guoqing; Wang, Junkai; Chen, Jianjun; Zang, Yunfei; Shan, Jingyi

doi:10.1016/j.ceramint.2023.08.071

Cited by 9 publications

(3 citation statements)

References 41 publications

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“…With the catalyst content of 1.00 wt.%, the carbon content reached its maximum value of 9.69%. The carbon content of samples containing the catalyst was higher than N0 sample, because a role was played by Ni on carbon fixation during the pyrolysis of organic precursor 24 . Ni(NO 3 ) 2 ·6H 2 O underwent complete decomposition to form NiO at 330°C 25 .…”

Section: Resultsmentioning

confidence: 99%

Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement

Feng,

Xiao,

Ding

et al. 2024

J Am Ceram Soc.

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The CNTs/MgAl2O4 whiskers composite reinforcement was prepared by catalytic carbon‐bed sintering and added to low‐carbon Al2O3‐C refractories to enhance the thermal shock resistance of refractories. The effects of Ni(NO3)2·6H2O content on the phase and microstructure of CNTs/MgAl2O4 were investigated. The nano‐indentation technology was used to quantitatively evaluate the effect of CNTs/MgAl2O4 on the thermal shock resistance of low‐carbon Al2O3‐C refractories, and the toughening mechanism of CNTs/MgAl2O4 on refractories was further investigated. The results revealed that the inner and outer diameters of the CNTs were approximately 5.69 and 16.26 nm, respectively. The CNTs winded around interlocking structural MgAl2O4 whiskers with a high aspect ratio (>100), which was beneficial to the dispersion of CNTs in the refractory matrix. The thermal shock resistance of low‐carbon Al2O3‐C refractories was significantly improved by adding 3.0 wt.% of CNTs/MgAl2O4 (named C3). The specific fracture energy of refractory matrix and residual strength ratio of C3 reached 141 N·m−1 and 39.2%, which were 29.4% and 97.0% higher than those of the blank sample (109 N·m−1 and 19.9%), respectively. This is because the refractory matrix was significantly reinforced by CNTs and MgAl2O4 whiskers, promoting the occurrence of “bridging” and “crack deflection” and the generation of microcracks in the refractory matrix.

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Section: Resultsmentioning

confidence: 99%

Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement

Feng,

Xiao,

Ding

et al. 2024

J Am Ceram Soc.

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“…The ability to mix refractory aggregates with CAC on-site ensures flexible technological solutions. Easy blending, convenient shaping, and high mixture stability determine the technological advantages that extend engineering capacities [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…The investigation by Suvorov et al [ 6 ] supported this inference, indicating that the SiO 2 modification improves the mechanical properties of refractory materials and enhances their thermal resistance. The micro-silica/alumina activation process also improves castables’ strength and sinterability temperature compared to the conventional alternatives [ 9 , 10 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Investigating the High-Temperature Bonding Performance of Refractory Castables with Ribbed Stainless-Steel Bars

Plioplys,

Antonovič,

Boris

et al. 2024

Materials

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Refractory materials containing calcium aluminate cement (CAC) are commonly used in the metallurgical and petrochemical industries due to their exceptional mechanical resistance, even at temperatures exceeding 1000 °C, and do not require additional reinforcement. This study seeks to advance this practice by developing ultra-high-performance structures that offer building protection against fire and explosions. Such structures require bar reinforcement to withstand accidental tension stresses, and the bond performance becomes crucial. However, the compressive strength of these materials may not correlate with their bond resistance under high-temperature conditions. This study investigates the bond behavior of ribbed stainless austenitic steel bars in refractory materials typical for structural projects. The analysis considers three chamotte-based compositions, i.e., a conventional castable (CC) with 25 wt% CAC, a medium-cement castable (MCC) with 12 wt% CAC, a low-cement castable (LCC), and a low-cement bauxite-based castable (LCB); the LCC and LCB castables contain 7 wt% CAC. The first three refractory compositions were designed to achieve a cold compressive strength (CCS) of 100 MPa, while the LCB mix proportions were set to reach a CCS of 150 MPa. Mechanical and pull-out tests were conducted after treatment at 400 °C, 600 °C, 800 °C, and 1000 °C; reference specimens were not subjected to additional temperature treatment. This study used X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) methods to capture the material alterations. The test results indicated that the bonding resistance, expressed in terms of the pull-out deformation energy, did not directly correlate with the compressive strength, supporting the research hypothesis.

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A review on graphite surface modification methods towards low carbon-containing refractories

Zhang,

Ding,

et al. 2024

J. Iron Steel Res. Int.

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Catalytic carbon-bed sintering of CNTs/calcium aluminate cement and its effects on thermal mechanical properties of refractory castables

Cited by 9 publications

References 41 publications

Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement

Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement

Investigating the High-Temperature Bonding Performance of Refractory Castables with Ribbed Stainless-Steel Bars

A review on graphite surface modification methods towards low carbon-containing refractories

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Catalytic carbon-bed sintering of CNTs/calcium aluminate cement and its effects on thermal mechanical properties of refractory castables

Cited by 9 publications

References 41 publications

Enhanced thermal shock resistance of low‐carbon Al2O3‐C refractories via CNTs/MgAl2O4 whiskers composite reinforcement

Enhanced thermal shock resistance of low‐carbon Al2O3‐C refractories via CNTs/MgAl2O4 whiskers composite reinforcement

Investigating the High-Temperature Bonding Performance of Refractory Castables with Ribbed Stainless-Steel Bars

A review on graphite surface modification methods towards low carbon-containing refractories

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Product

Resources

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Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement

Enhanced thermal shock resistance of low‐carbon Al₂O₃‐C refractories via CNTs/MgAl₂O₄ whiskers composite reinforcement