The kinetic parameters of the reduction of barium sulphate to barium sulphide using carbon monoxide fractions of 2.4-9.6% and temperatures of 850-1000 degrees C, using an isothermal thermogravimetric method, were obtained. This reaction has shown to be temperature and carbon monoxide concentration dependent. By variation in temperature, at constant CO fractions, an average activation energy of 149 (+/- 10) kJ/mol was observed. By changing the CO fraction at constant temperature, it is suggested that the reduction reaction is first order in CO. An overall reaction rate equation is proposed. (C) 2009 Elsevier B.V. All rights reserved.