US4789485A
Expired / Lapsed
US
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Clarification of bayer process liquors
Assignee: Ciba Specialty Chemicals Water Treatments Ltd
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Filing: 1986-07-17
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Granted: 1988-12-06
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Expires: 2006-07-17
Abstract
Abstract The clarification of a sodium aluminate liquor in the Bayer Process, especially the liquor obtained by Kelly filter filtration of the supernatant from the primary settling stage, is improved by flocculation with a polymer of the formula CH 2 ═C(R 1 )CONHR 2 NR 3 R 4 wherein R 1 is hydrogen or methyl, R 2 is straight or branched chain C 2-8 alkylene having at least 2 carbon atoms in the backbone and R 3 and R 4 are independently selected from C 1-4 alkyl.
Inventors
- 👤 John R. Field
- 👤 Gillian M. Moody
- 👤 Trevor K. Hunter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:27
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/46; C01F7/47
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
118 words
A process for separating inorganic suspended solids in a sodium aluminate liquor obtained in a Bayer Process wherein an effective amount of a flocculatng agent is added to the liquor containing suspended solids, the flocculating agent comprising a quaternised polymer having an intrinsic viscosity (IV) above 1 dl/g and having at least about 25% by weight quaternised recurring units derived from monomers of the formula CH.sub.2 ═C(R.sup.1)CONHR.sup.2 NR.sup.3 R.sup.4 wherein R 1 is hydrogen or methyl, R 2 is straight or branched chain C 2-8 alkylene having at least 2 carbon atoms in the backbone and R 3 and R 4 are independently selected from C 1-4 alkyl, and the flocculated suspended solids are separated from the liquor.
Claim 2
Dependent Claim
118 words
A process for separating inorganic suspended solids in a sodium aluminate liquor obtained in a Bayer Process wherein an effective amount of a flocculatng agent is added to the liquor containing suspended solids, the flocculating agent comprising a quaternised polymer having an intrinsic viscosity (IV) above 1 dl/g and having at least about 25% by weight quaternised recurring units derived from monomers of the formula CH.sub.2 ═C(R.sup.1)CONHR.sup.2 NR.sup.3 R.sup.4 wherein R 1 is hydrogen or methyl, R 2 is straight or branched chain C 2-8 alkylene having at least 2 carbon atoms in the backbone and R 3 and R 4 are independently selected from C 1-4 alkyl, and the flocculated suspended solids are separated from the liquor.
Claim 3
Dependent Claim
38 words
A process according to claim 1 in which the liquor is the slurry obtained by digesting bauxite with sodium hydroxide and the separation is conducted in two stages comprising a primary separation stage and a pressure filtration step.
Claim 4
Dependent Claim
18 words
A process according to claim 2 in which the quaternised polymer is added before the primary separation stage.
Claim 5
Dependent Claim
26 words
A process according to claim 3 in which the flocculant also includes at least one of non-ionic and anionic polymeric flocculant added before the primary stage.
Claim 6
Dependent Claim
20 words
A process according to claim 4 in which the quaternised polymer is added before the non-ionic or anionic polymeric flocculant.
Claim 7
Dependent Claim
23 words
A process according to claim 2 in which the quaternised polymer is added after the primary separation stage and before the filtration stage.
Claim 8
Dependent Claim
36 words
A process according to claim 1 or claim 6 in which the quaternised polymer is added to a sodium aluminate liquor containing below 0.3% suspended inorganic solids and the liquor is then subjected to pressure filtration.
Claim 9
Dependent Claim
14 words
A process according to claim 7 in which filtration is by a Kelly filter.
Claim 10
Dependent Claim
26 words
A process according to claim 1 in which R 1 is hydrogen or methyl, R 2 is 1,3-propylene and R 3 and R 4 are methyl.
Claim 11
Dependent Claim
35 words
A process according to claim 9 in which the quaternerized polymer is derived from 95 to 25% by weight of the quaternized monomer units and 5 to 75% by weight of ethylenically unsaturated non-ionic comonomer.
Claim 12
Dependent Claim
12 words
A process according to claim 10 in which the comonomer is acrylamide.
Claim 13
Dependent Claim
17 words
A process according to claim 11 in which the polymer has an IV of 3 to 10.
Claim 14
Dependent Claim
15 words
A process according to claim 1 in which the polymer is quaternised by methyl chloride.
Claim 15
Dependent Claim
35 words
A process according to claim 1 in which the quaternised polymer is derived from 95 to 25% by weight of the quaternised monomer units and 5 to 75% by weight of ethylenically unsaturated non-ionic comonomer.
Claim 16
Dependent Claim
12 words
A process according to claim 14 in which the comonomer is acrylamide.
Claim 17
Dependent Claim
16 words
A process according to claim 1 in which the polymer has IV of 3 to 10.
Claim 18
Dependent Claim
24 words
A process according to claim 1 in which the liquor has a temperature of at least 60° C. and pH of at least 13.
Claim 19
Dependent Claim
88 words
A process for separating inorganic suspended solids from a sodium aluminate liquor obtained in a Bayer process wherein an effective amount of a flocculating agent is added to the liquor containing the suspended solids, the flocculating agent comprising a quaternised polymer having an intrinsic viscosity of above 1 dl/g and having from 95 to 25% by weight quaternised recurring groups derived from monomers of the formula CH.sub.2 ═C(R.sub.1)CONHCH.sub.2 CH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 wherein R 1 is hydrogen or methyl, and the flocculated suspended solids are separated from the liquor.
Claim 20
Dependent Claim
88 words
A process for separating inorganic suspended solids from a sodium aluminate liquor obtained in a Bayer process wherein an effective amount of a flocculating agent is added to the liquor containing the suspended solids, the flocculating agent comprising a quaternised polymer having an intrinsic viscosity of above 1 dl/g and having from 95 to 25% by weight quaternised recurring groups derived from monomers of the formula CH.sub.2 ═C(R.sub.1)CONHCH.sub.2 CH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 wherein R 1 is hydrogen or methyl, and the flocculated suspended solids are separated from the liquor.
Claim 21
Dependent Claim
15 words
A process according to claim 18 in which the polymer is quaternised by methyl chloride.
Claim 22
Dependent Claim
12 words
A process according to claim 18 in which the comonomer is acrylamide.
Claim 23
Dependent Claim
18 words
A process according to claim 18 in which the polymer has an intrinsic viscosity of 3 to 10.
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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) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |