Claims
- 1. A process for preparing crystalline anhydrous sodium carbonate from saturated sodium carbonate aqueous solutions, the solutions containing not more than about 0.4% by weight of sulfate ions, comprising adding to said solutions from about 25 to 5,000 parts per million by weight of an additive selected from the group consisting of maleic acid-alkanol telomers having the formula: ##STR3## wherein n is an integer of about 1 to 8 and X represents RCHOH, R being either hydrogen or an alkyl group of 1 to 5 carbon atoms; sodium tripolyphosphate; benzoic acid; phenol; and mixtures of same; and evaporating water from said solutions at temperatures of from about 104.degree. to below 109.degree. C. whereby anhydrous crystalline sodium carbonate is formed.
- 2. The process of claim 1 wherein said additive is a maleic acid-methanol telomer.
- 3. The process of claim 1 wherein said additive is a mixture of maleic acid-methanol telomer and sodium tripolyphosphate.
- 4. The process of claim 3 wherein the quantity of said additive is at least about 35 parts per million.
- 5. Process of claim 1 wherein said additive is phenol.
- 6. Process of claim 1 wherein said additive is benzoic acid.
- 7. The process of claim 1 wherein said aqueous sodium carbonate solution is produced in the monohydrate process by calcining crude trona to prepare crude sodium carbonate, dissolving the crude sodium carbonate in water to produce a crude sodium carbonate solution, filtering said solution to remove insoluble materials therefrom, said solution being a saturated solution containing 25 to 30.5% sodium carbonate.
- 8. A continuous process for producing crystalline anhydrous sodium carbonate comprising continuously adding a saturated solution of sodium carbonate containing from about 25 to 5,000 parts per million of a mixture of a maleic acid-methanol telomer having the formula: ##STR4## wherein n is an integer of about 1 to 8 and X represents RCHOH, and sodium tripolyphosphate to a slurry of anhydrous sodium carbonate crystals in water having a density of about 30% by weight, said solution having no more than about 0.4% by weight of sulfate ions, while maintaining said slurry at a temperature of about 105.degree. to about 106.degree. C., continuously evaporating water from said slurry and crystallizing anhydrous sodium carbonate crystals in the presence of said telomer and sodium tripolyphosphate, withdrawing a portion of said slurry, separating said crystals from said withdrawn portion of said slurry, drying said crystals and recovering crystalline anhydrous sodium carbonate.
- 9. The process of claim 8 wherein the saturated solution contains at least 35 ppm of a mixture of said maleic acid-methanol telomer and sodium tripolyphosphate.
- 10. The process of claim 8 wherein the anhydrous sodium carbonate crystals have a bulk density of 65 to 68 pounds per cubic foot.
- 11. A continuous process for producing crystalline anhydrous sodium carbonate comprising continuously adding an aqueous solution of sodium carbonate to a slurry of anhydrous sodium carbonate crystals in water, said solution having no more than about 0.4% by weight of sulfate ions, maintaining said slurry at a temperature of from about 104.degree. to below 109.degree. C., maintaining in said slurry from about 25 to 5,000 parts per million of an additive selected from the group consisting of a maleic acid-methanol telomer having the formula ##STR5## wherein n is an integer of about 1 to 8 and X represents RCHOH, R being either hydrogen or an alkyl group of 1 to 5 carbon atoms; sodium tripolyphosphate; benzoic acid; phenol; and mixtures of same; continuously evaporating water from said slurry and crystallizing anhydrous sodium carbonate crystals in the presence of said additive, withdrawing a portion of said slurry, separating said crystals from the withdrawn portion of said slurry, drying said crystals and recovering crystalline anhydrous sodium carbonate.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-in-Part of U.S. Application Ser. No. 798,709, now abandoned filed on May 19, 1977 in the names of Joseph M. Ilardi and Eric Rau, which is a Continuation-in-Part of U.S. Application Ser. No. 651,943, filed on Jan. 23, 1976 in the names of Joseph M. Ilardi and Eric Rau, now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (2)
Number |
Date |
Country |
46-16664 |
May 1971 |
JPX |
48-17160 |
May 1973 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Sienko et al., Chemistry, 2nd Edition, McGraw Hill Book Co., N.Y., N.Y. 1961, pp. 196-199. |
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
798709 |
May 1977 |
|
Parent |
651943 |
Jan 1976 |
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