Mullite-based refractory castable engineering for the petrochemical industry

作者：Luz A P^*; Neto A B Silva; Santos T Jr; Medeiros J; Pandolfelli V C

来源：Ceramics International, 2013, 39(8): 9063-9070.

DOI：10.1016/j.ceramint.2013.05.001

• Mullite
• Binder
• Refractory castables
• Sintering additive

Refractory castables used in fluid catalytic converter (FCC) risers should present suitable particle erosion and thermal shock resistances at temperatures below 900 degrees C. Considering that calcium aluminate cement (CAC)-bonded refractories usually start their densification above 1200 degrees C, the use of sintering additives to induce faster densification is a promising technological alternative. Therefore, this work addresses the evaluation of mullite-based castables containing a boron-based sintering additive and CAC and/or hydratable alumina as the binder sources. Hot elastic modulus, cyclical thermal shock, hot modulus of rupture and cold erosion resistance measurements were carried out to evaluate the compositions. According to the attained results, adding 1.5 wt% of the evaluated sintering additive to the designed castables led to a remarkable increase of the hot modulus of rupture (maximum of 40.4 MPa at 800 degrees C for the CAC-containing refractory) and high erosion resistance (1.5-2.9 cm(3)) after pre-firing at 800 degrees C for 5 h. Moreover, the combination of CAC and hydratable alumina gave rise to an improved refractory (M-2CAC-2HA-S) showing a transient liquid formation at an increased temperature, high thermal shock resistance (no E decay after 8 thermal cycles, Delta T=800 degrees C) and high mechanical strength at 800 degrees C and 1000 degrees C.

• 出版日期2013-12