One-step synthesis of in-situ carbon-containing calcium aluminate cement as binders for refractory castables

Int J Applied Ceramic Tech

et al. 2020

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Slag corrosion is one of the main damage modes for refractory castables used in iron and steel metallurgy. The matrix plays vital roles for corrosion resistance of refractory castables. In the present paper, the properties of the Al2O3‐SiC‐C‐based trough castables with in situ carbon containing calcium aluminate cement (CCAC) and ball pitch as carbon sources, respectively, were comparatively investigated. The microstructures of the trough castables after corrosion were observed by field‐emission scanning electron microscopy. The results showed that after being corroded at 1450°C for 3 hours, the corrosion depth of Al2O3‐SiC‐C‐castables with CCAC as binder (A2) was 1.2 mm, 65.71% lower than that of the trough castables with ball pitch as carbon source (A1), though the content of carbon materials in the former was much lower than that of the latter. The reasons for these observations were that the in situ carbon materials of CCAC exhibit improved distribution in the matrices of castables and excellent oxidation resistance, resulting in lower porosity within the castables, and hindered the penetration of the molten slag at high temperatures. In addition, the Al2O3‐SiC‐C‐castables bonded by CCAC displayed good mechanical properties at room temperature and elevated temperature.

“…The in situ CCAC with phase composition close to that of Secar71 was synthesized, and the details have been reported in the literature. The carbon content of CCAC was 1.45 wt%.…”

Section: Methodsmentioning

confidence: 99%

“…In our previous works, the in situ carbon containing calcium aluminate cement (CCAC) and in situ nanocarbon containing calcium aluminate cement, whose phase compositions were close to those of Secar71, were synthesized. It was found that the corrosion resistance of MgO‐Al 2 O 3 castables bonded by CCAC was significantly improved.…”

Section: Introductionmentioning

confidence: 99%

Improved corrosion resistance of Al₂O₃‐SiC‐C castables through in situ carbon containing aluminate cement as binder

Int J Applied Ceramic Tech

et al. 2020

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“…Recently, the modification of refractory matrixes by in-situ carbon composites has gained popularity [19][20][21][22]. The present authors synthesized insitu carbon-containing calcium aluminate cement (CCAC) with the phase composition close to that of Secar71 via the carbon bed sintering method, and found that the water dispersion and oxidation resistance of CCAC were enhanced, and that the corrosion resistance of the MgO-Al 2 O 3 castables bonded by CCAC were remarkably improved [23][24][25].…”

Section: Introductionmentioning

confidence: 91%

“…The in-situ carbon containing calcium aluminate cement (CCAC) with the phase composition close to that of Secar71 was synthesized, and the details of the process were presented in our previous works [23,25]. The in-situ carbon content of CCAC was 1.45% by mass.…”

Section: Preparation Of Al 2 O 3 -Sic-c Castablesmentioning

confidence: 99%

Effect of in-situ carbon containing calcium aluminate cement on properties of Al₂O₃-SiC-C based trough castables

Journal of Asian Ceramic Societies

et al. 2020

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The properties of Al 2 O 3-SiC-C castables bonded by in-situ carbon containing calcium aluminate cement (CCAC) were investigated in this study. The results showed that after the Al 2 O 3-SiC-C castables were dried at 110°C, their cold crushing strength (CCS) and cold modulus of rupture (CMOR) increased with the percentage of CCAC. The sample with CCAC content exceeding 2.5% by mass (named C2.5) had higher CCS and CMOR values than those of the model Al 2 O 3-SiC-C castables (named BPS) with ball pitch as the carbon source. After being fired at 1100 and 1450°C, all the castables exhibited increased CCS and CMOR values, while the high apparent porosity of the BPS sample lowered its CCS and CMOR values. Compared with the BPS sample, the carbon materials of the castables bonded by CCAC exhibited improved dispersion in the matrix and excellent oxidation resistance, which enhanced the corrosion resistance of the refractory castables.

“…In our previous work, we presented synthesis of in situ carbon‐containing calcium aluminate cement (CCAC) with phase compositions close to that of the commercial cement Secar71, and used it as binders for refractory castables. The results shown that in situ carbons in the cement were uniformly dispersed between/embedded into calcium aluminate particles.…”

Section: Introductionmentioning

confidence: 99%

One‐step synthesis of in situ nanocarbon‐containing calcium aluminate cement in reducing atmosphere

Int J Applied Ceramic Tech

et al. 2019

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In order to overcome the problems caused by poor water wettability/dispersion and oxidation resistance of carbons for improving properties of carbon-containing refractory castables, we prepare in situ nanocarbon-containing cement through the carbonbed sintering method with calcium citrate tetrahydrate (CCT, C 12 H 10 Ca 3 O 14 ·4H 2 O) and Al 2 O 3 as raw materials, and FeCl 3 as a catalyst. In this paper, the carbonization process of CCT was analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis coupled with a FTIR. In addition, the synthesized cement was characterized through XRD, Raman spectroscopy, field-emission scanning electron microscopy, and highresolution transmission electron microscopy. The results show that the in situ carbon was generated through carbonization of calcium aconitic acid which was generated by pyrolysis of CCT, accompanying with overflowing of H 2 O, CO 2 , CO, and CH 4 .Interestingly, as the sintering temperature increases, the freshly generated carbons were transformed into nanofiber and nanoflake carbons under the action of Fe catalyst. After sintering at 1500°C for 4 hours, the phase compositions of the synthesized product approached to that of the commercial cement Secar71, and the in situ carbons with nanofiber and nanoflake morphologies dispersed in calcium aluminate grains. K E Y W O R D Scalcium aluminate cement, carbon-bed sintering synthesis, in situ nanocarbon