Process for producing calcium carbonate and products thereof
AssigneeJ.M. Huber Corporation
InventorsJohn A. Kosin, Claude R. Andrews
Life of this patent
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Abstract
A process for producing calcium carbonate from calcium hydroxide derived from, for example, limestone, comprises injecting a gas containing carbon dioxide into a recirculating stream flowing in a recycle piping system in communication with a reaction vessel. The carbon dioxide containing gas is injected at a turbulent area located in the recycle piping system. By controlling reaction parameters including pH and temperature, novel calcium carbonate products are formed by the process.
Claims20
A method for producing calcium carbonate, comprising the steps of:
- (a) providing an aqueous calcium hydroxide slurry in a reaction vessel;
- (b) continuously recirculating at least a portion of the aqueous slurry through a recycle piping system in communication with the reaction vessel;
- and
- (c) injecting a gas comprising carbon dioxide into the recirculating aqueous slurry at a turbulent area located in the recycle piping system until the pH of the aqueous slurry in the reaction vessel is in the approximate range of from 8 to 10, at which time the gas injection is discontinued.
A method for producing calcium carbonate, comprising the steps of:
- (a) providing a reaction vessel containing water;
- (b) continuously recirculating at least a portion of the water through a recycle piping system in communication with the reaction vessel;
- (c) injecting a gas comprising carbon dioxide into the recirculating water at a turbulent area located in the recycle piping system until the pH of the water is in the approximate range of from 5 to 7;
- and
- (d) adding calcium hydroxide to the reaction vessel while continuing the gas injection at a rate to provide the resultant slurry formed in the reaction vessel with a pH value in the approximate range of from 8 to 10.
A method for producing calcium carbonate, comprising the steps of:
- (a) providing an aqueous calcium hydroxide slurry in a reaction vessel;
- (b) continuously recirculating at least a portion of the aqueous slurry through a recycle piping system in communication with the reaction vessel;
- (c) injecting a gas comprising carbon dioxide into the recirculating aqueous slurry at a turbulent area located in the recycle piping system until the pH of the aqueous slurry in the reaction vessel is at a first interim value in the approximate range of from 8 to 10, at which time the gas injection is discontinued;
- (d) continuing the recirculation of at least a portion of the aqueous slurry after the gas injection has been discontinued until the pH of the aqueous slurry in the reaction vessel rises to a second value above said first interim value as calcium carbonate which forms at the surface of calcium hydroxide particles flakes off and exposes new calcium hydroxide surfaces;
- and
- (e) again injecting a gas comprising carbon dioxide into the recirculating aqueous slurry at a turbulent area located in the recycle piping system until the pH of the aqueous slurry is at a third final value in the approximate range of from 8 to 10, at which time the gas injection is discontinued.
Dependencies are inferred from the claim text.