This work describes the crystal chemistry of synthetic mullite doped with Fe, Mn, Cr, Co, V, Pr, Cd, Ni, Cu, Zn and Zr. The synthesis was achieved at 1500°C for 4 h starting from caolinite and aluminum hydroxide. The solubility of the doping element in mullite was investigated. Synthetic mullites can be classified with respect to their degree of crystallization: (1) good crystallization (Fe-, Mn-, V-mullite); (2) rather good crystallization (undoped-, Cr-, Co-, Ni-, Pr-, Zn-, Zr-mullite); (3) poor crystallization (Cd-, Cu-mullite). The application of mullite as a bulk pigment in stoneware products and as a component for "matt" glazes was promising only for the latter application.
Synthesis of mullite from kaolinite: Use in tradiational ceramics as stain or glaze component / Porta, A.; Gualtieri, A. F.. - In: CERAMURGIA. - ISSN 0045-6152. - 33:3-4(2003), pp. 111-122.