Titania slag as a ceramic pigment

The phase transformations and colouring mechanisms that occur during the ceramic processing of titania slag were investigated using XRF-EDS, XRD, DRS and laboratory-scale application in glazed and unglazed tiles. The slag transforms to pseudobrookite, undergoing a drastic colour change during firing as a consequence of thermal oxidation with Fe(2+) to Fe(3+) and Ti(3+) to Ti(4+) reactions. The intense brown colour imparted by titania slag is stable at both low (up to 1050 degrees C) and high (around 1200 degrees C) temperatures and is suitable for porcelain stoneware tiles. In through-body application, titania slag enables 'spotting' effects to be achieved. (c) 2007 Elsevier Ltd. All rights reserved.