Different SiAlONs (X, O’, AlN polytypoid, beta) are prepared by carboreduction under nitrogen of coal-mine schists, varying three synthesis parameters (carbon percentage, reaction time, reaction temperature) and using a new heating procedure. Iron oxides, present in the starting product, react with silicon to give iron silicides. beta-SiAlONs begin to crystallize at 1300 degrees C, The optimum conditions for getting a pure phase are 30 mass % of carbon, 1400 degrees C, and 2 hours. Two morphologies are observed in the final product : fibers and spheres.