In the current work the separation of nickel from alumina is proposed when it is present in the following mixtures: 10 wt% Ni+90 wt% Al2O3, 12 wt% NiO+88 wt% Al2O3, making use of a tubular reactor, with a flow of 2 1/2 of gaseous chlorine and from 500 to 800 degrees C. The final products of the reaction, extracted from the hottest zones of the reactor where characterized as NiCl2 and NiCl2 center dot 6H(2)O, and the predominating phase of alumina condensed with NiCl2 UP to 700 degrees C was gamma-Al2O3. Thermogravimetric (TG) measurements were carried out in a mixed flux Of Cl-2 and Ar in non-isothermal conditions up to 950 degrees C. The beginning of the reaction in the first mixture was detected at 384 degrees C and close to 653 degrees C the volatilization of NiCl2 started. Besides, NiO reacts at 473 degrees C and NiCl2 volatilizes at 577 degrees C. There is no reaction with Cl-2 and no phase transition of gamma-Al2O3. in order to find out the reaction rates, mass changes of the reactants were measured under the same gaseous flow and in isothermal conditions. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.