Phase development during thermal treatment of a fast-setting cordierite-mullite refractory

N. HIPEDINGER, A.N. SCIAN Y E.F. AGLIETTI.

Procedia Materials Science

Elsevier

Lugar: Amsterdam; Año: 2015 p. 305 - 312

AbstractCordierite based materials are widely used in high temperature applications due to their good thermo-mechanical properties andthermal shock resistance. They are generally employed in the kiln furniture (shelves, brackets, bearing plates) for firing ceramicpieces. Because of its low expansion coefficient and dielectric properties, cordierite is also used in advanced ceramics, catalystsupports automotive, industrial waste gas purification and parts subjected to sudden temperature changes. The low intrinsicstrength of the cordierite may be compensated by the presence of mullite, forming a composite material of cordierite-mullite,extending its use to somewhat higher temperatures, at the expense of a slight increase in the thermal expansion coefficient. In thiswork a cordierite-mullite precursor was prepared from a mixture of magnesium oxide, calcined alumina, silica fume andmonoaluminum phosphate solution that produces fast setting at room temperature (~20 minutes) and then, by calcination,cordierite-mullite is generated. The evolution of the mineralogical phases was studied from room temperature to 1350 °C by Xraydiffraction, differential thermal analysis and thermogravimetry. A possible sequence of chemicals reactions throughout theheat treatment is also proposed. Adding refractory aggregates to this precursor leads to obtaining a fast-setting concrete, suitablefor the formation of individual pieces or repair service at moderately high temperatures. A summary of its main properties is alsoincluded.