A Study on the Preparation of Mullite

This thesis is interested in preparing high purity mullite powder, 3Al₂O₃.2SiO₂, by hydrolysis method at low temperature. Aluminum nitrate nona hydrate, ANN, Al (NO₃)₃.9H₂O, is used as a source of alumina while tetraethyl orthosilicate, TEOS, Si (OC₂H₅)₄, is the source of silica. It is required to obtain the maximum quantity of mullite powder precursors at the same time the best quality. Among the factors that maximize the production quantity are the reactants concentrations by wt. % mullite solids to be 1, 2 and 3 wt. % which yield the standard molar ratio of alumina to silica as 3:2. In addition to concentration; both the temperature (50, 60 and 70 °C) and ph of the reacting medium (4, 6 and 8) are selected. Taguchi design of experiment (DOE) - as a first step in carrying out the experiment set - is applied. For the three factors previously mentioned, three levels for each one are also selected. This choice corresponds to an orthogonal array L9, so from Taguchi design, nine experimental runs alternatives are considered