| 摘要 |
<p>The iron content of iron-, silicon- and aluminium-containing raw materials e.g. bauxites, clay minerals, colliery rocks, and red minds, is reduced by passing an aqueous hydrochloric acid solution the concentration of which exceeds 100 g./l, through one or more beds of the unground but preferably prebroken and sized raw material, at a temperature below 90 DEG C, preferably at room temperature, optionally in the presence of a flocculating agent. The ferric chloride produced is separated and subjected to pyrolytic decomposition to produce ferric oxide. The bed residue of reduced iron content can be utilized in the Bayer process for producing alum earth, as a starting substance of ceramic industry or, after treatment with sulfuric acid, dissolution in hydrochloric acid or water, elimination of silica, and pyrolytic decomposition of the aluminium sulfate obtained, as an alumina concentrate.</p> |
