Abstract: The invention relates to an improved process for reducing the iron content of iron-, silicon- and aluminium-containing raw materials and for producing ferric oxide, optionally along with an alumina concentrate. According to the invention the iron content of mineral raw materials, e.g. bauxites, clay minerals, colliary rocks, red muds, etc. is eliminated by passing through one or more beds prepared from the unground but preferably prebroaken and sized raw material an aqueous hydrochloric acid solution, the concentration of which exceeds 100 g./lit., at a temperature below 90.degree. C., preferably at room temperature, optionally in the presence of a flocculating agent. By pyrolytic decomposition of the ferric chloride prepared ferric oxide can be produced.