Claims
- 1. A method for the production of an anhydrous mixed alkali metal carbonate from potassium hydroxide and sodium bicarbonate using equimolar amounts of each compound, wherein:
- a) to an aqueous solution of potassium hydroxide is added an equimolar amount of sodium bicarbonate to produce an unsaturated solution of a thermally stable alkaline compound resulting from the reaction of said potassium hydroxide and sodium bicarbonate and b) said solution of said compound is heated to approximately 100.degree. C. and is then sent to a spray drier which has an outlet temperature about 93.degree. C., thereby yielding an anhydrous mixed potassium sodium carbonate.
- 2. A method according to claim 1, wherein to a solution of up to 22% weight of potassium hydroxide is added an equimolar amount of sodium bicarbonate to form a saturated solution of a mixed potassium sodium carbonate.
- 3. A method according to claim 1 wherein the bulk density of the anhydrous mixed alkali carbonate produced is 500-750 grams per liter.
- 4. A method according to claim 1, wherein the air for the spray drier that contains combustion gases is substantially free of contaminants.
- 5. A method for the production of sodium carbonate monohydrate from sodium bicarbonate and sodium hydroxide using equimolar amounts of each compound and dehydrating the resulting crystals to produce anhydrous neutral sodium carbonate as a dense soda-ash, wherein:
- a) sodium hydroxide in solution is introduced into a suspension of sodium carbonate monohydrate crystals in a saturated solution of sodium carbonate at a temperature about 35.degree. C., and part of the sodium carbonate in solution crystallizes as additional sodium carbonate monohydrate on the crystals in suspension,
- b) solid sodium bicarbonate in an equimolar amount to the sodium hydroxide in solution is then added and additional sodium carbonate monohydrate crystallizes on the sodium carbonate monohydrate crystals in suspension,
- c) the sodium carbonate monohydrate crystals are separated and dehydrated yielding dense soda-ash, anhydrous sodium carbonate of bulk density 950-1100 grams per liter, and
- d) the mother liquor is evaporated to eliminate the water introduced with the sodium hydroxide in step (a) and sodium carbonate monohydrate crystallizes to produce a suspension of said sodium carbonate monohydrate crystals in a saturated solution of sodium carbonate, said suspension being recycled to step (a).
- 6. A method according to claim 5, wherein in step (a) to a saturated solution containing about 30.5% sodium carbonate and sodium carbonate monohydrate crystals in suspension is added 50% sodium hydroxide to produce a solution having about 8.2% by weight of sodium hydroxide.
- 7. A method according to claim 5, wherein to the sodium hydroxide solution is added a stoichiometric equivalent of solid sodium bicarbonate.
- 8. A method according to claim 5, wherein in step (d) water introduced with the sodium hydroxide is evaporated from the mother liquid at a temperature below 107.50.degree.C. so that the sodium carbonate monohydrate crystallizes.
- 9. A method according to claim 5, wherein sodium carbonate monohydrate is separated from the mother liquor and dehydrated to yield an anhydrous sodium carbonate as the dense soda-ash.
- 10. A method for the production of light soda-ash with bulk density of 500-700 grams per liter from sodium hydroxide and sodium bicarbonate using equimolar amounts of each compound, wherein:
- a) to a solution of about 15.2% by weight of sodium hydroxide is added an equimolar amount of sodium bicarbonate to produce an approximately 30.5% solution carbonate at a temperature of about 35.degree. C. or more,
- b) the approximately 30.5% solution of sodium carbonate is heated to approximately 100.degree. C. and then dried in a spray drier with an outlet air temperature above 93.degree. C.
- 11. A method according to claim 10, wherein the bulk density of the anhydrous sodium carbonate of 500-700 grams per liter is varied by changing the concentration of the solution fed to the spray drier, wherein a higher concentration of solids in the solution results in a higher bulk density of the dried anhydrous product.
- 12. A method according to claim 10, wherein the heated air for the spray drier that contains combustion gases is free of contaminants.
Parent Case Info
This application is a continuation of application(s) Ser. No. 08/287,870 now abandoned filed on Aug. 9, 1994.
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
744521 |
Jul 1970 |
BEX |
Continuations (1)
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Number |
Date |
Country |
Parent |
287870 |
Aug 1994 |
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