Synthesis of mullite from kaolinite: Use in tradiational ceramics as stain or glaze component

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.