The syngas reaction has been studied using a laterite iron mineral, promoted with K and Mn. In situ activation under syngas, as well as pre-treatment with H2 followed by CO under mild and more severe conditions were tested. These activation procedures led to different iron phase compositions and to different catalytic selectivities. The C2-C4/CH4 ratio was significantly lower for those catalysts which after reaction showed the presence of hexagonal carbide and magnetite compared to the solid, which showed the highest proportion of Hagg carbide.