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US4059673A
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US
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Production of bauxite and aluminium chloride of low iron content
Assignee: Rio Tinto Aluminium Holdings Ltd
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Filing: 1975-04-10
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Granted: 1977-11-22
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Expires: 1995-04-10
Abstract
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.
Inventors
- 👤 Robin David Holliday
- 👤 David John Milne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:08
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/48; C01F7/56; C01F7/58; C01F7/60
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
116 words
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° to 750° C with a gas mixture comprising 20 to 40% SO 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.
Claim 2
Dependent Claim
116 words
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° to 750° C with a gas mixture comprising 20 to 40% SO 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.
Claim 3
Dependent Claim
15 words
Process according to claim 1 in which the chlorinating gas contains chlorine and carbon monoxide.
Claim 4
Dependent Claim
18 words
Process according to claim 1 in which the chlorination in the second step is effected at 650°-750° C.
Claim 5
Dependent Claim
12 words
Process according to claim 1 in which the aluminous material is bauxite.
Claim 6
Dependent Claim
30 words
Process according to claim 1 including a preliminary dehydration stage in which entrained and combined water is removed from the raw material by heating at temperatures up to 750° C.
Claim 7
Dependent Claim
89 words
Process for removing iron from bauxite which comprises a. heating the bauxite raw material at temperatures not exceeding 750° C to remove entrained and combined water; b. treating the product of step (a) at temperatures from 400° to 750° C with a gas mixture consisting essentially of 20 to 40% SO 2 and 80 to 60% CO by volume to sulphidize iron contained therein; c. treating the product of step (b) at temperatures between 430° and 750° C with chlorine and removing the iron chloride so produced by volatilization.
Claim 8
Dependent Claim
89 words
Process for removing iron from bauxite which comprises a. heating the bauxite raw material at temperatures not exceeding 750° C to remove entrained and combined water; b. treating the product of step (a) at temperatures from 400° to 750° C with a gas mixture consisting essentially of 20 to 40% SO 2 and 80 to 60% CO by volume to sulphidize iron contained therein; c. treating the product of step (b) at temperatures between 430° and 750° C with chlorine and removing the iron chloride so produced by volatilization.
Claim 9
Dependent Claim
26 words
Process according to claim 6 wherein the purified bauxite resulting from step (c) is chlorinated with a chlorinating gas consisting essentially of chlorine and carbon monoxide.
Claim 10
Dependent Claim
34 words
Process according to claim 7 in which said chlorinating step is carried out at temperatures from 650 to 750° C and the chlorinating gas is an approximately equimolar mixture of chlorine and carbon monoxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-21 | 1981-05-23 | 1981-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-21 | 1985-05-23 | 1985-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-21 | 1989-05-23 | 1989-11-22 | $7700.00 | Window Closed / Lapsed |