Engineering the Microstructural Parameters of Erosion Resistant High Alumina Castables

D. T. Gomes1, V. A. A. Santos2, A. P. Luz2, V. C. Pandolfelli2

1 Petrobras, Rio de Janeiro, RJ, 21941-915, Brazil
2 Federal University of São Carlos, Materials Engineering Department, São Carlos, SP, 13565-905/Brazil

Revision 30.01.2018, 05.05.2018

Volume 10, Issue 3, Pages 84 - 92

Abstract

Different parameters (i.e., particle size distribution and packing, size and amount of coarse grains, and other features of the resulting microstructure) can affect the erosion resistance of refractory castables. In this sense, this work investigated the performance of high-alumina castable compositions containing: (i) different amounts of calcium aluminate cement (CAC) as binder, (ii) white or brown-fused alumina as coarse grains, (iii) distinct maximum particle size and distribution modulus of the formulations, and (iv) sodium borosilicate (0–5 mass-%) as a sintering additive, during erosion measurements. Besides the determination of the eroded volume of samples fred at distinct temperatures (600–1200 °C), apparent porosity and hot modulus of rupture of the designed formulations were also analysed. The obtained results indicated that the most promising evaluated composition comprised 10 mass-% of CAC as, specimens with lower cement amounts resulted in high eroded volume or even full erosion. No signifcant changes in the measured eroded volume could be detected for the refractory formulations containing white or brown-fused alumina aggregates and coarse grains with different particle size, as the matrix fraction (fine components) is the main area of the castables to be worn due to the SiC particles’ impact. The addition of sodium borosilicate to the castables helped to improve their erosion resistance (due to the generation of a boron-rich liquid phase and its further interaction with the other available oxides), when pre-fring the samples at intermediate temperatures (800 °C, 1000 °C or 1200 °C for 5 h).

Keywords

erosion, particle size distribution, calcium aluminate cement, refractory castables

References

[1] Luz, A.P.; et al.: High-alumina boron-containing refractory castables. Int. J. Appl. Ceram. Technol. (2014). doi:10.1111/ijac.12310 [2] Braulio, M.A.L.; et al.: Nano-bonded wide temperature range designed refractory castables. J. Amer. Ceram. Soc. 95 (2012) 1100–1104. doi:10.1111/j.1551-2916.2011.05053.x [3] Luz, A.P.; et al.: Monoaluminum phosphate-bonded refractory castables for petrochemical application. Ceram. Int. 42 (2016) 8331–8337. doi:10.1016/j.ceramint.2016.02.047 [4] Wiederhorn, S.; Roberts, D.E.: A technique to investigate high temperature erosion of refractories. Ceram. Bull. 55 (1976) 185–189 [5] Myhre, B.; Hundere, A.M.: The use of particle size distribution in the development of refractory castables. Proc. of XXV Alafar Congr., San Carlos de Bariloche, Argentina, 1996, 1–4 [6] Myhre, B.: The effect of particle size distribution on fow of refractory castables. Proc. of 30 Ann. Refract.. Symp., St Louis, USA, 1994, 1-17 [7] Studart, A.R.; et al.: High-alumina multifunctional refractory castables. Amer. Ceram. Soc. Bull. 80 (2001) 34–40 [8] Ismael, M.R.; Salomão, R.; Pandolfelli, V.C.: Colloidal silica bonded refractory castables: optimization of the particle size distribution. Refractory Appl. News. 13 (2008) 10–15 [9] Wiederhorn, S.: Erosion of castable refractories. Refract. Appl. 2 (1997) 2–6 [10] Ritter, J.E.; Rosenfeld, L.; Jakus, K.: Erosion and strength degradation in alumina. Wear 111 (1986) 335–346 [11] Wiederhorn, S.; Hockey, B.J.: Effect of material parameters on the erosion resistance of brittle materials. J. Mater. Sci. (1983) 766–780 [12] Crowley, M.S.: The infuence of particle size on the erosion resistance of refractory concretes. Amer. Ceram. Soc. Bull. 48 (1969) 707–710 [13] Prestes, E.; et al.: Hot-erosion of nano-bonded refractory castables for petrochemical industries. Ceram. Int. 39 (2013) 2611–2617 [14] Engman, U.: Erosion testing of refractories – a new testing procedure Wear 186–187 (1995) 215–223 [15] Luz, A.P.; Pandolfelli, V.C.; Braulio, M.A.L.: Particle size distribution and packing desing. Refractory Castable Engineering. Baden-Baden 2015, 91–155 [16] Pileggi, R.G.; et al.: Novel rheometer for refractory castables. Amer. Ceram. Soc. Bull. 79 (2000) 54–58 [17] Luz, A.P.; Borba, N.Z.; Pandolfelli, V.C.: Mechanical strength and hydrate products evolution of calcium aluminate cement for endodontic applications. Ceramica 60 (2014) 192–198. doi:10.1590/S0366-69132014000200005 (In Portuguese) [18] Lee, W.E.; et al.: Castable refractory concretes. Int. Mater. Rev. 46 (2001) 145–167. doi:10.1179/095066001101528439 [19] Luz, A.P.; et al.: Mullite-based refractory castable engineering for the petrochemical industry. Ceram. Int. 39 (2013) 9063–9070. doi:10.1016/j.ceramint.2013.05.001 [20] Scrivener, K.L.; Nemati, K.M.: The percolation of pore space in the cement paste/aggregate interfacial zone of concrete. Cem. Concr. Res. 26 (1996) 35–40 [21] Roy, D.M.; Scheetz, B.E.; Silbee, M.R.: Processing of optimised cements and concretes via particle packing. MRS Bull. 18 (1993) 45–49. [22] Luz, A.P.; Braulio, M.A.L.; Pandolfelli, V.C.: Refractory Castable Engineering. Baden-Baden 2015, 91–149 [23] Oliveira, I.R.; et al.: Dispersion and particles packing – principles and applications in ceramics processing. Fazendo Arte Editorial, São Paulo, 2000, 119–137 (in Portuguese) [24] Maizo, I.D.G.; et al.: Boron sources as sintering additives for alumina-based refractory castables. Ceram. Int. 43 (2017) 10207–10216. doi:10.1016/j.ceramint.2017.05.047 [25] Swamy, V.; Jung, I.H.; Decterov, S.A.: Thermodynamic modeling of the Al O –B O –SiO system. J. Non. Cryst. Solids. 355 (2009) 1679–1686. doi:10.1016/j.jnoncrysol.2009.06.036 [26] Schafer, U.L.; Kuzel, H.I.: Neues Jahrbuch für Mineralogie, Monatshefte, 4–5 (1967) 131 [27] V.D. Eisenhüttenleute, Slag Atlas, 2 Ed., Düsseldorf 1995, 99 [28] Gielisse, P.J.; Foster, W.R.: The system Al O –B O . Nature 195 (1962) 69–70

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