Secondary raw materials like steelworks slag or other vanadium bearing industry wastes like catalysts and oil burner ash can be used for the production of vanadium before their final disposal. Therefore, as in primary processing, alkaline roasting has to be carried out in a rotary kiln or multiple hearth furnace. This process transforms the vanadium, strongly embedded within the spinel mineral structure, into leachable vanadates. Mathematical modeling of this process for the establishment of simulation programs and for model based controller design requires accurate models of the chemical reaction kinetics. In this article a set of equations describing the reaction rate of the vanadium roast process and its derivation is presented. Validation showed good agreement between simulation and measurement data. (C) 2003 Elsevier Ltd. All rights reserved.