# US 5,707,960 A · Amorphous sodium silicate-metal sulfate composite powder

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- Number: US 5,707,960 A
- Document ID: US5707960A
- Status: Granted
- Kind: A
- Application number: 08/605,374
- Filed: 1996-02-22
- Granted: 1998-01-13
- Earliest claimed: 1995-02-23
- Assignees: Tokuyama Corporation
- Inventors: Yoshiki Fukuyama; Genji Taga
- Web page: https://patentgrep.com/patent/US5707960A

## CPC

- C11D 3/046: {Salts}
- C11D 3/08: Silicates
- C11D 3/122: {Sulfur-containing, e.g. sulfates, sulfites or gypsum}
- C11D: DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL

## Abstract

Amorphous sodium silicate-metal sulfate composite powder having water softening power and having small hygroscopicity, and useful as a detergent builder is provided. This amorphous sodium silicate-metal sulfate composite powder is characterized in that it contains a metal sulfate, for example, sodium sulfate, as solid solution, and when the SiO.sub.2 /Na.sub.2 O molar ratio is expressed by n and the specific surface area thereof is expressed by S (m.sup.2 /g), n and S satisfy the following expressions: 1.60.ltoreq.n.ltoreq.2.80 0.10.ltoreq.S.ltoreq.2.00 , provided that it is assumed that the molar number of Na.sub.2 O is the molar number of Na.sub.2 O based on sodium silicate, and does not contain the molar number of Na.sub.2 O based on sodium sulfate in the case where the metal sulfate is sodium sulfate. This powder is prepared by grinding sodium silicate cullet containing the metal sulfate as solid solution.

## Claims

### Claim 1

Amorphous sodium silicate-metal sulfate composite powder which contains the metal sulfate as solid solution, and is such that when the SiO.sub.2 /Na.sub.2 O molar ratio is expressed by n and the specific surface area is expressed by S (m.sup.2 /g), n and S satisfy the following expressions
1.60.ltoreq.n.ltoreq.2.80
0.10.ltoreq.S.ltoreq.2.00
, provided that the molar number of Na.sub.2 O is the molar number of Na20 based on sodium silicate, and does not contain the molar number of Na.sub.2 O based on sodium sulfate in the case where the metal sulfate is sodium sulfate;
wherein the metal sulfate is contained in an amount of 0.3 to 9.0% by weight in terms of a sulfur element and wherein said composite powder has an average primary particle size of 1.2 to 12 .mu.m and an average secondary particle size of 1.8 to 22 .mu.m.

### Claim 2 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the SiO.sub.2 /Na.sub.2 O molar ratio n satisfies the following expression
1.80.ltoreq.n.ltoreq.2.20.

### Claim 3 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the specific surface area S (m.sup.2 /g) satisfies the following expression
0.50.ltoreq.S.ltoreq.1.50.

### Claim 4 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the metal sulfate is an alkali metal sulfate, an alkaline earth metal sulfate or aluminum sulfate.

### Claim 5 (depends on 4)

The amorphous sodium silicate-metal sulfate composite powder according to claim 4, wherein the alkali metal sulfate is lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate or cesium sulfate.

### Claim 6 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the metal sulfate is contained in an amount of 0.7 to 7.0% by weight in terms of a sulfur element.

### Claim 7 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the metal sulfate is contained in an amount of 1.0 to 4.0% by weight in terms of a sulfur element.

### Claim 8 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein the amount of fine crystals thereof, calculated from the area of the broad peak in the X-ray diffraction halo pattern in comparison with the halo pattern, is under 20% by volume.

### Claim 9 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein its average primary particle size is 1.6 to 12 .mu.m.

### Claim 10 (depends on 1)

The amorphous sodium silicate-metal sulfate composite powder according to claim 1, wherein its average secondary particle size is 2.5 to 22 .mu.m.

### Claim 11 (depends on 1)

A detergent builder comprising the amorphous sodium silicate-metal sulfate composite powder according to claim 1.