US4810682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of useful materials including synthetic nepheline from Bayer red mud
Assignee: Rio Tinto Aluminium Ltd
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Filing: 1987-06-10
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Granted: 1989-03-07
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Expires: 2007-06-10
Abstract
Abstract A process for production of useful materials including a product of similar composition to nepheline involves contacting a slurry of red mud with sulphur dioxide to dissolve components of the red mud that are soluble in sulphurous acid, removing residual undissolved solids by filtration, and recovering a filtrate containing soda, alumina and silica values, removing free water from the filtrate to produce a crystallized residue, and calcining the crystallized residue.
Inventors
- 👤 William H. Andrews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:46
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/20; C01B33/26; C01B33/28; C01B33/2807; C01B33/2892; C01D; C01D5/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
96 words
Process for the treatment of Bayer Red Mud to produce useful materials therefrom, said process comprising: (a) contacting a slurry of red mud with sulphur dioxide to dissolve components of red mud that are soluble in sulphurous acid, (b) removing residual undissolved solids by filtration, and recovering a filtrate containing sodium monoxide, alumina and silica values, (c) removing free water from the filtrate to produce a residue, and (d) calcining the residue to produce at least one material suitable for use in the glass or ceramic industries as a source of sodium monoxide, alumina or silica.
Claim 2
Dependent Claim
96 words
Process for the treatment of Bayer Red Mud to produce useful materials therefrom, said process comprising: (a) contacting a slurry of red mud with sulphur dioxide to dissolve components of red mud that are soluble in sulphurous acid, (b) removing residual undissolved solids by filtration, and recovering a filtrate containing sodium monoxide, alumina and silica values, (c) removing free water from the filtrate to produce a residue, and (d) calcining the residue to produce at least one material suitable for use in the glass or ceramic industries as a source of sodium monoxide, alumina or silica.
Claim 3
Dependent Claim
22 words
Process according to claim 1 in which sulphur dioxide is recovered from step (c) and step (d) and recycled to step (a).
Claim 4
Dependent Claim
27 words
Process according to claim 2 in which step (d) is carried out in an inert or reducing atmosphere to yield sulphur dioxide for recycle to step (a).
Claim 5
Dependent Claim
16 words
Process according to claim 1 in which step (d) is carried out in an oxidising atmosphere.
Claim 6
Dependent Claim
12 words
Process according to claim 1 in which the product contains synthetic nepheline.
Claim 7
Dependent Claim
11 words
Process according to claim 1 in which the product contains hauynite.
Claim 8
Dependent Claim
22 words
Process according to claim 1 in which step (d) is carried out in an oxidising atmosphere and the product contains sodium sulphate.
Claim 9
Dependent Claim
96 words
Process for the production of synthetic nepheline from Bayer Red Mud which comprises: (a) contacting a slurry of Red Mud with sulphur dioxide to dissolve components of the Red Mud that are soluble in sulphurous acid. (b) removing residual undissolved solids by filtration, and recovering the filtrate containing sodium monoxide, alumina and silica values, (c) removing free water from the filtrate to produce a residue, (d) calcining the residue in an inert or reducing atmosphere, (e) recycling sulphur dioxide yielded in step (d) to (a), and (f) recovering synthetic nepheline as a produce from step (d).
Claim 10
Dependent Claim
96 words
Process for the production of synthetic nepheline from Bayer Red Mud which comprises: (a) contacting a slurry of Red Mud with sulphur dioxide to dissolve components of the Red Mud that are soluble in sulphurous acid. (b) removing residual undissolved solids by filtration, and recovering the filtrate containing sodium monoxide, alumina and silica values, (c) removing free water from the filtrate to produce a residue, (d) calcining the residue in an inert or reducing atmosphere, (e) recycling sulphur dioxide yielded in step (d) to (a), and (f) recovering synthetic nepheline as a produce from step (d).
Claim 11
Dependent Claim
40 words
The product of a process according to claim 7, said product containing sodium sulphate and at least one composition selected from the group consisting of nepheline and hauynite, the mineralogy of the product being determined by the temperature of calcination.
Claim 12
Dependent Claim
9 words
The product of a process according to claim 1.
Claim 13
Dependent Claim
19 words
Process according to claim 1 in which sulphur dioxide is recovered from step (b) and recycled to step (a).
Claim 14
Dependent Claim
18 words
Process according to claim 1 in which sulphur dioxide is recovered from step(c) and recycled to step (a).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-06 | 1992-09-05 | 1993-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-06 | 1996-09-05 | 1997-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-06 | 2000-09-05 | 2001-03-07 | $7700.00 | Window Closed / Lapsed |