US3870780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of sodium carbonate
Assignee: Henley Group Inc
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Filing: 1972-09-14
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Granted: 1975-03-11
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Expires: 1992-09-14
Abstract
Abstract A method of treating an aqueous solution of sodium carbonate containing soluble silicates and suspended insoluble matter by digesting the solution at a temperature within the range of about 185* to 220*F. for a time sufficent to substantially reduce the soluble silicates contained therein, separating the solution from the insoluble matter, and obtaining purified sodium carbonate by crystallization. The method is particularly applicable to the treatment of solutions of calcined trona.
Inventors
- 👤 Joel P Guptill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:48
CPC Classifications
C; C01; C01D; C01D7/00; C01D7/22; C01D7/26
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
94 words
A METHOD OF REDUCING SOLUBLE SILICATES FROM AN AQUEOUS SODIUM CARBONATE SOLUTION PREPARED FROM CALCINED TRONA HAVING AT LEAST ABOUT 20 PERCENT BY WEIGHT SODIUM CARBONATE DISSOLVED THEREIN, AND CONTAINING AS IMPURITIES, SOLUBLE SILICATES AND SUSPENDED INSOLUBLE MATTER, WHICH METHOD COMPRISES THE STEPS OF: DIGESTING THE AQUEOUS SODIUM CARBONATE SOLUTION IN THE ABSENCE OF ADDITIVES TO INSOLUBILIZE THE SILICATES AT A TEMPERATURE WITHIN THE RANGE OF 160* AND 240*F. FOR A TIME SUFFICIENT TO REMOVE AT LEAST 25 PERCENT OF THE SOLUBLE SILICATES CONTAINED THEREIN; AND SEPARATING THE DIGESTED SOLUTION FROM CONTAINED INSOLUBLE MATTER.
Claim 2
Independent Claim
94 words
A METHOD OF REDUCING SOLUBLE SILICATES FROM AN AQUEOUS SODIUM CARBONATE SOLUTION PREPARED FROM CALCINED TRONA HAVING AT LEAST ABOUT 20 PERCENT BY WEIGHT SODIUM CARBONATE DISSOLVED THEREIN, AND CONTAINING AS IMPURITIES, SOLUBLE SILICATES AND SUSPENDED INSOLUBLE MATTER, WHICH METHOD COMPRISES THE STEPS OF: DIGESTING THE AQUEOUS SODIUM CARBONATE SOLUTION IN THE ABSENCE OF ADDITIVES TO INSOLUBILIZE THE SILICATES AT A TEMPERATURE WITHIN THE RANGE OF 160* AND 240*F. FOR A TIME SUFFICIENT TO REMOVE AT LEAST 25 PERCENT OF THE SOLUBLE SILICATES CONTAINED THEREIN; AND SEPARATING THE DIGESTED SOLUTION FROM CONTAINED INSOLUBLE MATTER.
Claim 3
Independent Claim
94 words
A method of reducing soluble silicates from an aqueous sodium carbonate solution prepared from calcined trona having at least about 20 percent by weight sodium carbonate dissolved therein, and containing as impurities, soluble silicates and suspended insoluble matter, which method comprises the steps of: digesting the aqueous sodium carbonate solution in the absence of additives to insolubilize the silicates at a temperature within the range of 160* and 240*F. for a time sufficient to remove at least 25 percent of the soluble silicates contained therein; and separating the digested solution from contained insoluble matter.
Claim 4
Independent Claim
94 words
A method of reducing soluble silicates from an aqueous sodium carbonate solution prepared from calcined trona having at least about 20 percent by weight sodium carbonate dissolved therein, and containing as impurities, soluble silicates and suspended insoluble matter, which method comprises the steps of: digesting the aqueous sodium carbonate solution in the absence of additives to insolubilize the silicates at a temperature within the range of 160* and 240*F. for a time sufficient to remove at least 25 percent of the soluble silicates contained therein; and separating the digested solution from contained insoluble matter.
Claim 5
Dependent Claim
22 words
The method of claim 1 wherein the aqueous solution has a sodium carbonate concentration of between 20 and 35.5 percent sodium carbonate.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the aqueous solution is substantially saturated with respect to sodium carbonate.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein the digestion is carried out at a temperature within the range of 185* to 210*F.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the digestion is carried out for between 1/2 and 8.0 hours.
Claim 9
Dependent Claim
15 words
The process of claim 1 wherein the trona is calcined at temperatures of about 500*C.
Claim 10
Dependent Claim
40 words
The method of claim 1 wherein sodium carbonate is obtained by crystallizing said sodium carbonate from the solution separated from the contained insoluble matter under crystallization conditions sufficient to effect formation of a stable crystal phase of said sodium carbonate.
Claim 11
Dependent Claim
14 words
The method of claim 7 wherein the crystalline sodium carbonate is sodium carbonate monohydrate.
Claim 12
Dependent Claim
30 words
The method of claim 7 wherein the sodium carbonate crystals are separated from the concentrated solution and dried and the concentrated solution free of crystals is recovered as mother liquor.
Claim 13
Dependent Claim
33 words
The method of claim 9 wherein the aqueous sodium carbonate solution comprises a solution of trona in an aquEous medium consisting, at least in part, of the mother liquor from the crystallization step.
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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) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |