Production of bauxite and aluminium chloride of low iron content
AssigneeComalco Limited
InventorsRobin David Holliday, David John Milne
Life of this patent
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Abstract
Removal of iron from aluminous material such as bauxite is effected by treatment with a gas mixture comprising sulphur dioxide and carbon monoxide in a first step, followed by chlorination in a second step whereby ferric chloride is produced and removed by volatilization. Aluminium chloride of low iron content may be obtained from the purified aluminous material by chlorination.
Claims8
Process for production of aluminum chloride of low iron content from aluminous materials containing iron, which comprises in a first step reacting an aluminous material containing iron at temperatures from 400.degree. to 750.degree. C with a gas mixture comprising 20 to 40% SO.sub.2 by volume, the balance being CO apart from minor diluents, to produce iron sulphide;
- in a second step, heating the product of the first step in the presence of chlorine, whereby ferric chloride is produced and removed by volatilization, whereby a purified aluminous material of low iron content is obtained;
- and in a third step, chlorinating said purified aluminous material with a chlorinating gas to produce aluminum chloride of low iron content.
Process for removing iron from bauxite which comprises
- a. heating the bauxite raw material at temperatures not exceeding 750.degree. C to remove entrained and combined water;
- b. treating the product of step (a) at temperatures from 400.degree. to 750.degree. C with a gas mixture consisting essentially of 20 to 40% SO.sub.2 and 80 to 60% CO by volume to sulphidize iron contained therein;
- c. treating the product of step (b) at temperatures between 430.degree. and 750.degree. C with chlorine and removing the iron chloride so produced by volatilization.
Dependencies are inferred from the claim text.