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Interceram - International Ceramic Review

, Volume 64, Issue 4–5, pp 177–181 | Cite as

Sintering Effect of Al and a Boron Source in High-Alumina Nano-Bonded Refractory Castables

  • E. Prestes
  • A. P. Luz
  • D. T. Gomes
  • V. C. Pandolfelli
Review Papers

Abstract

Petrochemical refractory end-users face difficulties in finding commercial products with optimized thermo-mechanical properties for the low operational temperatures (<900°C) in fluid catalytic cracking units. Blending colloidal binders with sintering additives in castable compositions is an interesting alternative that may overcome the limited densification of conventional cement-bonded systems. This work investigated the effects associated with use of Al and/or boron sources added to high-alumina colloidal silica-bonded castables sintered at temperatures up to 1000°C. In situ measurements of hot elastic modulus and hot modulus of rupture, and XRD and SEM analyses were performed to explain the reaction mechanisms and phase evolution associated with Al and boron-based compound performance at high temperatures. The test results indicate that added boron induced formation of Al4B2O9 and generated liquid phase in the microstructure of the castables. Aluminium powder was oxidized (giving rise to alumina), which resulted in increased castable stiffness. This latter transformation was only observed in colloidal silica-containing compositions. The best thermo-mechanical performance in the 600–815°C range was obtained for castables containing both Al and boron.

Keywords

castable colloidal silica sintering additives alumina 

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Copyright information

© Springer Fachmedien Wiesbaden 2015

Authors and Affiliations

  • E. Prestes
    • 1
  • A. P. Luz
    • 1
  • D. T. Gomes
    • 2
  • V. C. Pandolfelli
    • 1
  1. 1.Materials Engineering DepartmentFederal University of São CarlosSão CarlosBrazil
  2. 2.Petrobras, CENPES/EB-AB-G-E/EEQRio de JaneiroBrazil

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