www.ireng.org


Technical Paper


Figure 9: Macro-TGA of MCC and NCC


Figure 10: Macro-TG of LCC (300 K/h)


Figure 11: Permeability as function of curing Temperature (24h) castable formulations. The deflocculating active compound REFPAC® 500


has been developed for alumina spinel and alumina magnesia castables. It has been demonstrated that it stabilizes the setting time in relation to the temperature dependence that one typically observes for refractory castables. The biggest effect is seen at 5°C where RP500 gives a significant accelerating effect without using Lithium salt as accelerator, while at 35°C only small differences have been observed compared to the PCE based reference mix. The permeability enhancing active compound REFPAC® MIPORE 20 creates at lower temperature higher gas permeability than PP- fibers. Furthermore the formation of gel-like calcium aluminate hydrates favours a lower de-hydration temperature. The removal of a large amount of water becomes possible at temperatures below 150ºC which helps to avoid high steam pressure build-up inside the castable and minimizes the risk of explosive steam spalling.


Figure 12: Temperature at which 2/3 of water is removed from cubes of different size


References


1. Zetterström C, Pommay J, Frier E, Wöhrmeyer C. Novel deflocculation system for silica fume containing castables with enhanced robustness to raw material variations. AcerS St. Louis Refractory section, 50th Symposium on Refractories, March 2014.


Ann.


2. Zetterström C, Auvray JM, Wöhrmeyer C, Parr C. Enhanced permeability for a rapid dry-out of refractory castables, Proc. Unitecr15, Vienna, 2015.


3. Auvray JM, Zetterström C, Wöhrmeyer C, Parr C, Kebli F. The impact of permeability for a rapid dry-out of refractory castables, Proc. Unitecr15, Vienna, 2015.


4. Nouri-Khezrabat M, Braulio MAL, Pandolfelli VC, Golestani-Fard F, Rezaie, HR. Nano-bonded refractory castables. Ceram. Int., May 2013, 39 (4), 3479-97.


Figure 13: Castable matrix of A15 (24h, 20ºC) September 2017 Issue ENGINEER THE REFRACTORIES


Figure 14: Castable matrix of A15-MP20 (24h, 20°C) 19


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