# US 5,707,912 A · Process for the treatment of clay materials to provide slurries having improved rheological properties

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- Number: US 5,707,912 A
- Document ID: US5707912A
- Status: Granted
- Kind: A
- Application number: 08/617,964
- Filed: 1996-03-18
- Granted: 1998-01-13
- Earliest claimed: 1996-03-18
- Assignees: Thiele Kaolin Company
- Inventors: Robert A. Lowe; Prakash B. Malla
- Web page: https://patentgrep.com/patent/US5707912A

## CPC

- C09C 1/42: Clays
- C01P 2006/22: Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
- Y10S 106/04: Bentonite
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Clay materials, such as kaolin, containing expandable layer-silicates are chemically treated with a source of magnesium cations, followed by a pH adjustment, to provide a slurry product having improved rheological properties.

## Claims

### Claim 1

A process for treating clay materials which contain expandable layer-silicates, wherein the process comprises the steps of:
A. obtaining an initial slurry of a clay material which contains expandable layer-silicates;
B. treating the clay slurry with a source of magnesium cations; and
C. adding a base solution to the treated clay slurry to achieve a molar ratio of hydroxide:magnesium ions of about 1.0:1.0 to about 2.5:1.0,
whereby a treated clay is produced having rheological properties which are improved over the rheological properties of the initial clay slurry when compared at equivalent solids content.

### Claim 2 (depends on 1)

A process as defined by claim 1 wherein the expandable layer-silicates are smectites, illites or a mixture thereof.

### Claim 3 (depends on 1)

A process as defined by claim 1 wherein the expandable layer-silicates are smectites.

### Claim 4 (depends on 1)

A process as defined by claim 1 wherein the clay material is kaolin clay.

### Claim 5 (depends on 1)

A process as defined by claim 1 wherein the magnesium cations are derived from magnesium chloride, magnesium nitrate, magnesium hydroxide, magnesium acetate or a mixture thereof.

### Claim 6 (depends on 1)

A process as defined by claim 1 wherein the magnesium cations are derived from magnesium chloride.

### Claim 7 (depends on 1)

A process as defined by claim 1 wherein the base solution is sodium hydroxide, potassium hydroxide, ammonium hydroxide, lithium hydroxide, soda ash or a mixture thereof.

### Claim 8 (depends on 1)

A process as defined by claim 1 wherein the base solution is sodium hydroxide.

### Claim 9 (depends on 1)

A process as defined by claim 1 wherein the base solution is soda ash.

### Claim 10 (depends on 1)

A process as defined by claim 1 wherein the molar ratio of hydroxide:magnesium ions is about 1.0:1.0 to about 2.0:1.0.

### Claim 11

A clay slurry produced by a process which comprises the steps of:
A. obtaining an initial slurry of a clay material which contains expandable layer-silicates;
B. treating the clay slurry with a source of magnesium cations; and
C. adding a base solution to the treated clay slurry to achieve a molar ratio of hydroxide:magnesium ions of about 1.0:1.0 to about 2.5:1.0,
whereby a treated clay is produced having rheological properties which are improved over the rheological properties of the initial clay slurry when compared at equivalent solids content.

### Claim 12 (depends on 11)

A clay slurry as defined by claim 11 wherein the expandable layer-silicates are smectites, illites or a mixture thereof.

### Claim 13 (depends on 11)

A clay slurry as defined by claim 11 wherein the expandable layer-silicates are smectites.

### Claim 14 (depends on 11)

A clay slurry as defined by claim 11 wherein the clay material is kaolin clay.

### Claim 15 (depends on 11)

A clay slurry as defined by claim 11 wherein the magnesium cations are derived from magnesium chloride, magnesium nitrate, magnesium hydroxide, magnesium acetate or a mixture thereof.

### Claim 16 (depends on 11)

A clay slurry as defined by claim 11 wherein the magnesium cations are derived from magnesium chloride.

### Claim 17 (depends on 11)

A clay slurry as defined by claim 11 wherein the base solution is sodium hydroxide, potassium hydroxide, ammonium hydroxide, lithium hydroxide, soda ash or a mixture thereof.

### Claim 18 (depends on 11)

A clay slurry as defined by claim 11 wherein the base solution is sodium hydroxide.

### Claim 19 (depends on 11)

A clay slurry as defined by claim 11 wherein the base solution is soda ash.

### Claim 20 (depends on 11)

A clay slurry as defined by claim 11 wherein the molar ratio of hydroxide:magnesium ions is about 1.0:1.0 to about 2.0:1.0.