Patent US3681931A successfully refreshed from Google Patents.
US3681931A
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Treatment of phosphate rock slimes by freezing
Assignee: KEY WEST HOLDINGS Inc
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Filing: 1970-03-11
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Granted: 1972-08-08
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Expires: 1990-03-11
Abstract
Abstract This process is a method of treating an aqueous inorganic colloidal suspension to make it amenable to separation by decantation, filtration, and centrifugation and comprises statically freezing the suspension and thawing the thus frozen suspension prior to separation by decantation, filtration, and centrifugation. In the preferred embodiment of the process, the suspension is kept in a frozen state for a predetermined length of time after the static freezing. This process is particularly adept at making phosphate rock slimes amenable to separation by the above-named methods.
Inventors
- 👤 Pablo Hadzeriga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:49
CPC Classifications
C; C05; C05B; C05B11/00; C05B11/04; C05B11/06; B; B03; B03B; B03B1/00; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/32; C01B3/00; C01B3/02; C01B3/06; C01B3/12; C01B3/16; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/181; C01B33/183; C02; C02F; C02F11/00; C02F11/18; C02F11/20; B03D; B03D1/00; B03D1/02; B03D1/021
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
18 words
The method as defined in claim 1 wherein the frozen suspension is statically thawed in the thawing step.
Claim 2
Dependent Claim
17 words
The method as defined in claim 1 wherein the freezing temperature is between -1* and -100* C.
Claim 3
Dependent Claim
18 words
The process as defined in claim 1 wherein the freezing temperature is between about -20* and -80* C.
Claim 4
Dependent Claim
26 words
The method as defined in claim 1 wherein the total solids content of the phosphate rock slime is between about 5 percent and about 10 percent.
Claim 5
Dependent Claim
18 words
The meThod as defined in claim 1 wherein the phosphate rock slime is an acid leached phosphate slime.
Claim 6
Dependent Claim
15 words
The method as defined in claim 1 wherein the freezing temperature is about -20* C.
Claim 7
Dependent Claim
24 words
The method as defined in claim 7 wherein the phosphate rock slime is kept in a frozen state for at least about 24 hours.
Claim 8
Dependent Claim
97 words
A process for the treatment of phosphate rock slimes which comprises: subjecting the phosphate rock slimes to a freezing temperature, without agitation of the suspension, for a period sufficient to separate and freeze a substantial portion of the water therein; subjecting the phosphate rock slimes to a thawing temperature without agitation for a period sufficient to melt the frozen water therein to yield a bottom layer of phosphate rock slimes concentrated suspension and an upper layer of liquid containing essentially water and dissolved matter; and filtering off the upper thawed liquid layer from the thawed concentrated suspension.
Claim 9
Dependent Claim
30 words
The process defined in claim 9 including the additional step of keeping the phosphate rock slimes in a frozen state for a predetermined length of time after the freezing step.
Claim 10
Dependent Claim
28 words
The process defined in claim 9 including the additional step of decanting the upper layer of liquid from the thawed phosphate rock slimes prior to the filtration step.
Claim 11
Dependent Claim
30 words
The process defined in claim 9 including the additional step of centrifuging the thawed phosphate rock slimes to effect further concentration of the concentrated suspension prior to the filtering step.
Claim 12
Dependent Claim
18 words
The process defined in claim 9 wherein the phosphate rock slime is an acid leached phosphate rock slime.
Claim 13
Dependent Claim
19 words
The process defined in claim 9 wherein the freezing temperature is between about -20* C. and about -80* C.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |