Reaction sintering of zircon-dolomite mixtures

Dolomite-zircon mixtures have become interesting for finding alternate sour ces to improve the production of high magnesia refractories. To asses this option, two minerals, dolomite and zircon were selected, as economically ra w materials, to produce MEO-CaZrO3-Ca2SiO4 materials. The reaction sinterin g mechanism of zircon-dolomite mixtures were investigated using finely grou nd Spanish dolomite and zircon powders as starting materials. During the he at treatment decomposed dolomite (CaO + MgO) reacts with zircon. from 1000 to 1200 degreesC. through a series of reactions before the final stable com pounds are formed. From the results obtained the reaction occurs prior to s intering in the presence of an amorphous transitory phase, magnesium calciu m silicate phase and the limiting process during the reaction is the format ion of Ca2SiO4. The sintering occurs after the end of the reaction so by co ntrolling the whole process it is possible to obtain materials with control led porosity. In the present work it is shown that reaction sintering of zi rcon-dolomite mixtures is a feasible route to obtain MgO-CaZrO3-beta -Ca2Si O4 porous materials for refractory insulators or as filters applications. ( C) 2001 Elsevier Science Ltd. All rights reserved.