High-titanium slag can be oxidised by exposure to oxygen or water vapour, since the slag contains trivalent titanium and divalent iron; such oxidation is used in slag upgrading processes. The presence of water vapour may increase the rate of oxidation. To test this, samples of crushed high-titanium slag were oxidised in various mixtures of oxygen, argon, and water vapour, in a fluidised bed, at 800 degrees C, for up to 2 h. The presence of water vapour did increase the degree of oxidation, without changing the nature of the reaction products, which were rutile, pseudobrookite with increased iron content, and some anatase. (c) 2005 Elsevier Ltd. All rights reserved.