US3714792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Freezing and melting treatment of red mud slurries to aid solid separation
Assignee: Kaiser Aluminum and Chemical Corp
•
Filing: 1971-08-19
•
Granted: 1973-02-06
•
Expires: 1991-08-19
Abstract
Abstract Red mud slurries, resulting from the alkaline digestion of bauxite and consisting of finely divided red mud particles dispersed in an aqueous medium, are subjected to a freeze-thaw treatment to enhance the settling properties and the filterability of the dispersed particles. Lowering the temperature of the slurry to a temperature required to freeze at least a portion of the aqueous medium, followed by thawing, was found to impart significantly accelerated settling and filtration rates.
Inventors
- 👤 J Murphy
- 👤 P Bolmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:10
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/06; C01F7/066
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
116 words
A process for treating red mud slurries derived as digestion residue from the alkaline Bayer process treatment of bauxite and consisting of finely divided insoluble solids suspended in an aqueous medium in order to improve the settling and the filtration rate of the solids, which comprises: a. lowering the temperature of the slurry to at least the temperature required to freeze the aqueous medium; b. maintaining the slurry at this lowered temperature for a time sufficient to solidify by freezing at least a portion of the aqueous medium; c. raising the temperature of the slurry to a temperature sufficient to melt the solidified portion of the aqueous medium; and d. recovering the solids by gravitational separation.
Claim 2
Dependent Claim
116 words
A process for treating red mud slurries derived as digestion residue from the alkaline Bayer process treatment of bauxite and consisting of finely divided insoluble solids suspended in an aqueous medium in order to improve the settling and the filtration rate of the solids, which comprises: a. lowering the temperature of the slurry to at least the temperature required to freeze the aqueous medium; b. maintaining the slurry at this lowered temperature for a time sufficient to solidify by freezing at least a portion of the aqueous medium; c. raising the temperature of the slurry to a temperature sufficient to melt the solidified portion of the aqueous medium; and d. recovering the solids by gravitational separation.
Claim 3
Dependent Claim
20 words
Process according to claim 1, wherein the finely divided solids possess an average particle size of 10 microns or less.
Claim 4
Dependent Claim
20 words
Process according to claim 2, wherein the finely divided solids possess an average particle size of 1 micron or less.
Claim 5
Dependent Claim
16 words
Process according to claim 1, wherein the slurry temperature is lowered to below about -10* C.
Claim 6
Dependent Claim
30 words
Process according to claim 1, wherein the slurry temperature is lowered from about 0* C to about -10* C at a rate of about 1* to 4* C per minute.
Claim 7
Dependent Claim
20 words
Process according to claim 1, wherein the solids content of the slurry is about 10 to 40 percent by weight.
Claim 8
Dependent Claim
25 words
Process according to claim 1, wherein a portion of the iron minerals of the bauxite subjected to the Bayer process is present as goethite (FeO(OH)).
Claim 9
Dependent Claim
12 words
Process according to claim 1, wherein the bauxite is of Jamaican origin.
Claim 10
Dependent Claim
13 words
Process according to claim 1, wherein the gravitational separation is accomplished by settling.
References Cited (Backward Citations)
US938432A
Cited
US2922761A
Cited
US3311449A
Cited
US3148024A
Cited
US3397953A
Cited
US3508884A
Cited
US3681931A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |