The determination of Ti2O3 in titania slags: a comparison of different methods of analysis

Nine titania slags, consisting mostly of ferropseudobrookite (denoted as M3O5), were investigated with the aim of evaluating various methods to estimate their Ti2O3 content. Direct methods include the determination of the Ti3+ content using chemical titration and X-ray absorption spectroscopy (XAS) at the Ti K edge. Indirect determinations of the Ti2O3 content are based on the bulk chemical composition analysed by inductively coupled plasma optical emission spectrometry and the analysis of pseudobrookite cell parameters using X-ray diffraction. It was found that the use of bulk chemistry, the FeO contents, as well as the a unit cell dimensions of the M3O5 phase give acceptable estimates, provided that the slags are not oxidised on cooling to room temperature. Only the direct XAS and titration methods determine the actual Ti3+ or Ti2O3 contents and are not influenced by the degree of oxidation of the slags. The XAS results provide a valuable independent validation of the titration method. It is concluded that the titration method is still the most practical and reliable method for estimating Ti3+ contents.