US 5,853,686 A · Calcium carbonates of altered crystal habit or morphology and methods for producing same

Abstract

Methods are disclosed in which first and second reactant salts and, optionally, a complexing agent are added to a non-aqueous reaction solvent to form a reaction system. The reactant salts, which are substantially soluble and reactive with each other in water to form a first crystallite of calcium carbonate, are present in the reaction solvent in relative amounts that are sufficient to form a desired amount of the calcium carbonate in the reaction system. The complexing agent, if present, is a crown ether or other cyclic or acyclic polydentate chelating agent that, in the reaction solvent, forms chelation complexes with at least one of the reactant salts. Reaction of the first and second reactant salts in the reaction solvent forms a second crystallite precipitate comprising crystals of calcium carbonate having a different habit or morphology from calcium carbonate crystals in the first crystallite that would otherwise be formable in water by reaction of similar amounts of the first and second reactant salts.

Claims16

Dependent claims

A method for forming a crystallite of calcium carbonate, the method comprising;

(a) adding a calcium salt and a carbogate salt, at least one of the salts being substantially soluble in water, and a complexing agent to an essentially non-aqueous reaction solvent to form a reaction system, the calcium, salt and carbonate salt being reactive with each other in water to form a first crystallite of calcium carbonate, the complexing agent being soluble in the reaction solvent and being selected from a group consisting of crown ethers, tris(metboxyethoxyethyl)amines, poly(ethylene glycols), and glymes, the complexing agent being capable of forming chelation complexes with at least one of the salts in the reaction solvent, the calcium salt and carbonate salt being added to the reaction solvent for reaction with each other in the reaction system to form a calcium carbonate;
(b) allowing the calcium salt and carbonate salt to react with each other in the reaction system to form a second crystalline precipitate, the second crystallite comprising crystals of calcium carbonate that have a different habit or morphology from calcium carbonate crystals in the calcium carbonate in the first crystallite that would otherwise be formable in water by reaction of the calcium salt and carbonate salt without the complexing agent.

A method for forming a crystallite of calcium carbonate, the method comprising:

(a) providing a calcium salt and a carbonate salt, at least one of said salts being substantially soluble in water, said salts reacting with each other in water to form a first crystallite of calcium carbonate;
(b) providing a complexing agent that is soluble in and can form chelation complexes with the calcium salt in an organic solvent, the complexing agent being selected from a group consisting of crown ethers, tri(methoxyethoxyethyl)amines, poly(ethylene glycols), and glymes;
(c) adding the calcium salt and carbonate salt along with the complexing agent to the organic solvent in a reaction system, the calcium salt and carbonate salt reacting with each other to form a calcium carbonate in the reaction system;
and
(d) allowing the calcium salt and carbonate salt to react with each other in the reaction system to form a second crystallite precipitate of the calcium carbonate in the organic solvent, the second crystallite precipitate comprising crystals of the calcium carbonate that have a different habit or morphology from crystals of the calcium carbonate in the first crystallite that would be formable in water by reaction of the salts without the complexing agent.

2 more elements

Dependencies are inferred from the claim text.

Calcium carbonates of altered crystal habit or morphology and methods for producing same

Life of this patent

Calcium carbonates of altered crystal habit or morphology and methods for producing same

Life of this patent

Abstract

Claims16