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US 4,459,272 AGranted
Dry carbonation process
AssigneeChurch & Dwight Co., Inc.
InventorsJohn P. Krieg, Anthony E. Winston
Life of this patent
Estimating the term…
Abstract
A process for the dry carbonation of an ammonium or alkali metal carbonate containing material, or a mixture thereof, for conversion to the corresponding bicarbonate containing material comprising reacting in the solid phase an ammonium and/or alkali metal carbonate containing material with liquid water in a carbon dioxide rich atmosphere at a particle temperature of from about 125.degree. F. to about 240.degree. F. for a period of time sufficient to effect the desired conversion of the carbonate groups of said carbonate containing material to bicarbonate groups, the reaction temperature being controlled by the evaporation of liquid water at the reaction site and the removal of the resulting water vapor from the reactor atmosphere.
Claims20
In a process for carbonating a water-soluble alkali metal or ammonium carbonate material free of water of hydration in the solid phase to convert at least 15% by weight of the carbonate material to the corresponding alkali metal or ammonium bicarbonate, the improvement comprising
- reacting the carbonate material in solid, particulate form with liquid water in a carbon dioxide-containing atmosphere under a total pressure of from 1 to 10 atmospheres to form a solution of the carbonate reactant within each individual particle and to crystallize the bicarbonate product formed therein, and
- carrying out the reaction by contacting the solid carbonate material, the liquid water and the gaseous carbon dioxide for from 5 to 60 minutes, the longer the reaction time, the higher degree of conversion, while maintaining the temperature of the particulate reactant within the range of from 125.degree. to 240.degree. F., by:
- (a) adding both relatively dry carbon dioxide gas and a liquid water aliquot over a substantial portion of the reaction period, the liquid water aliquot being added in an amount of from 2 to 50 percent by weight of the carbonate, and adding additional liquid water to replace at least a portion of that removed as vapor during the carbonation reaction, the total amount of liquid water present in the reaction mixture being:
- (i) sufficient to insure substantially uniform contact between the liquid water and the solid particles, but not so much as to agglomerate and cake the particles, and
- (ii) sufficient to moderate the rate of heat release by the carbonation reaction to maintain the temperature of the particulate reactant as aforesaid;
- (b) mixing the particulate mass to effect intimate contact of the carbonate material, the liquid water and the carbon dioxide;
- (c) maintaining the carbon dioxide at a partial pressure of from 0.2 to 0.9 atmosphere when the total pressure is 1 atmosphere, and at proportionately higher partial pressures at greater total pressures;
- (d) evaporating liquid water adjacent the particulate reactant to cool the reacting particles;
- and
- (e) removing the water vapor-containing atmosphere to continue the evaporation of water to cool the reacting particles and maintain them within the aforesaid temperature range.
7 more elements
In a process for carbonating anhydrous sodium carbonate to sodium bicarbonate, the improvement comprising
- reacting the anhydrous sodium carbonate in solid, particulate form with liquid water in a carbon dioxide-containing atmosphere under a total pressure of from 1 to 3 atmospheres to form a solution of sodium carbonate within each individual particle, to convert at least 15% by weight of the anhydrous sodium carbonate to sodium bicarbonate, and to crystallize the sodium bicarbonate, and
- carrying out the reaction by contacting the anhydrous sodium carbonate, the liquid water and the gaseous carbon dioxide for from 20 to 45 minutes, the longer the reaction time, the higher degree of conversion, while maintaining the temperature of the particulate reactant within the range of from 125.degree. to 240.degree. F., by:
- (a) adding both relatively dry carbon dioxide gas and a liquid water aliquot over a substantial portion of the reaction period, the liquid water aliquot being added in an amount of from 2 to 50 percent by weight of the carbonate, and adding additional liquid water to replace at least a portion of that removed as vapor during the carbonation reaction, the total amount of liquid water present in the reaction mixture being:
- (i) sufficient to insure substantially uniform contact between the liquid water and the solid particles, but not so much as to agglomerate and cake the particles, and
- (ii) sufficient to moderate the rate of heat release by the carbonation reaction to maintain the temperature of the particulate reactant as aforesaid;
- (b) mixing the particulate mass to effect intimate contact of the anhydrous sodium carbonate, the liquid water and the carbon dioxide;
- (c) maintaining the carbon dioxide at a partial pressure of from 0.2 to 0.9 atmosphere when the total pressure is 1 atmosphere, and at proportionately higher partial pressures at greater total pressures;
- (d) evaporating liquid water adjacent the particulate reactant to cool the reacting particles;
- and
- (e) removing the water vapor-containing atmosphere to continue the evaporation of water to cool the reacting particles and maintain them within the aforesaid temperature range.
7 more elements
In a process for carbonating a water-soluble, hydrated alkali metal or ammonium carbonate material in the solid phase to convert at least 15% by weight of the carbonate values present to the corresponding bicarbonate, the improvement comprising
- reacting the carbonate material in solid, particulate form with liquid water in a carbon dioxide-containing atmosphere under a total pressure of from 1 to 10 atmospheres to form a solution of the carbonate reactant within each individual particle and to crystallize the bicarbonate product formed therein, and
- carrying out the reaction by contacting the solid carbonate material, the liquid water and the gaseous carbon dioxide for from 5 to 60 minutes, the longer the time, the higher the degree of conversion, while maintaining the temperature of the particulate reactant within the range of from 125.degree. to 240.degree. F., by:
- (a) adding both relatively dry carbon dioxide gas and a liquid water aliquot over a substantial portion of the reaction period, the liquid water aliquot being added in an amount of from 2 to 50 percent by weight of the carbonate, and adding additional liquid water to replace at least a portion of that removed as vapor during the carbonation reaction, the total amount of liquid water present in the reaction mixture being:
- (i) sufficient to insure substantially uniform contact between the liquid water and the solid particles, but not so much as to agglomerate and cake the particles, and
- (ii) sufficient to moderate the rate of heat release by the carbonation reaction to maintain the temperature of the particulate reactant as aforesaid;
- (b) mixing the particulate mass to effect intimate contact of the carbonate material, the liquid water and the carbon dioxide;
- (c) maintaining the carbon dioxide at a partial pressure of from 0.2 to 0.9 atmosphere when the total pressure is 1 atmosphere, and at proportionately higher partial pressures at greater total pressures;
- (d) evaporating liquid water adjacent the particulate reactant to cool the reacting particles;
- and
- (e) removing the water vapor-containing atmosphere to continue the evaporation of water to cool the reacting particles and maintain them within the aforesaid temperature range.
7 more elements
Dependencies are inferred from the claim text.