The paper explores several alternative ways for improving the performance of zinc ferrites, which are common high-throughput sorbents used in hot gas desulphurisation processes (IGCC). The catalysts have been prepared by supporting the pure oxides (zinc and iron oxides) in porous supports (sepiolite, ZrO2 and zeolite) that provides the necessary strength. The active phase (zinc ferrite) is "in situ" synthesized as combined mixed oxides with a spinel structure, produced after calcination at high temperature. It has been found that the preparation method has a strong influence on the spatial distribution of the chemical species inside the pellet. In some cases, it is even possible to produce a profile where metallic oxides concentrate near the outer edge of the particle. According to XRD, it is found a preferential formation of enstatite phase rather than franklinite, due to substitution of interstitial ions in the framework of supports for Fe2+ and Zn2+. These conclusions set up strong requirements for the synthesis of specific sorbents in FGD reactions. This can be achieved by means of a combination of different preparation methodologies, which allow selecting the metallic ions and the supports in order to build the active spinels required for the FGD reaction. (C) 2004 Elsevier B.V. All rights reserved.