Ceramic raw materials from High Latium (Central Italy) consisting of halloysite-10 Å, amorphous silica, sanidine and other accessory phases were subjected to heat treatment by rapid- and slow-firing processes. The products were studied by X-ray diffraction and optical microscopy. The main newly-formed high-temperature phases were mullite and cristobalite. The discussion centres around the formation and features of these newly-formed crystalline phases. Particular attention is paid to any mineralogical differences between the products from the two modes of firing. © 1992.
Mullite and cristobalite formation in fired products starting from halloysitic clay / Gualtieri, A.; Bertolani, M.. - In: APPLIED CLAY SCIENCE. - ISSN 0169-1317. - 7:4(1992), pp. 251-262. [10.1016/0169-1317(92)90013-D]