# US 2014/0150693 A1 · Surfactant-coated hemihydrate gypsum and production method thereof

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- Number: US 2014/0150693 A1
- Document ID: US20140150693A1
- Status: Published application
- Kind: A1
- Application number: 14/234,602
- Filed: 2012-08-21
- Published: 2014-06-05
- Earliest claimed: 2011-09-08
- Assignees: Tokuyama Corporation
- Inventors: Shingo Hiranaka; Hiroyoshi Kato
- Web page: https://patentgrep.com/patent/US20140150693A1

## CPC

- C04B 11/005: {Preparing or treating the raw materials}
- C04B 11/024: Ingredients added before, or during, the calcining process, e.g. calcination modifiers
- C04B 20/1025: {Fats; Fatty oils; Ester type waxes; Higher fatty acids; Derivatives thereof}
- C04B 20/1029: {Macromolecular compounds}
- C04B 20/1037: {obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds}
- Y10T 428/2993: Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Surfactant-coated hemihydrate gypsum which is coated with 0.01 to 1 part by weight of a surfactant based on 100 parts by weight of hemihydrate gypsum, wherein the residual rate of the surfactant when the surfactant-coated hemihydrate gypsum is heated up to 300° C. is not less than 40 wt % of the amount of the surfactant before heating.

## Claims

### Claim 1

Surfactant-coated hemihydrate gypsum which is coated with 0.01 to 1 part by weight of a surfactant based on 100 parts by weight of hemihydrate gypsum, wherein
the residual rate of the surfactant when the surfactant-coated hemihydrate gypsum is heated up to 300° C. is not less than 40 wt % of the amount of the surfactant before heating.

### Claim 2 (depends on 1)

The surfactant-coated hemihydrate gypsum according to claim 1, wherein the coating amount of the surfactant is 0.1 to 0.6 part by weight based on 100 parts by weight of hemihydrate gypsum.

### Claim 3 (depends on 1)

The surfactant-coated hemihydrate gypsum according to claim 1, wherein the surfactant is at least one selected from the group consisting of sulfates of a polyoxyalkylene, alkali metal salts of a higher fatty acid, fatty acid esters of glycerin and polyoxyalkylene-based nonionic surfactants.

### Claim 4 (depends on 1)

The surfactant-coated hemihydrate gypsum according to claim 1 which has a cumulative pore volume of not more than 0.5 mL/g.

### Claim 5 (depends on 1)

A method of producing the surfactant-coated hemihydrate gypsum of claim 1, comprising the step of heating a composition containing at least dihydrate gypsum and a surfactant at 110 to 200° C.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the dihydrate gypsum is at least one selected from the group consisting of natural gypsum, flue-gas desulfurized gypsum and recovered dihydrate gypsum which has undergone a crystallization step.

### Claim 7 (depends on 2)

The surfactant-coated hemihydrate gypsum according to claim 2, wherein the surfactant is at least one selected from the group consisting of sulfates of a polyoxyalkylene, alkali metal salts of a higher fatty acid, fatty acid esters of glycerin and polyoxyalkylene-based nonionic surfactants.

### Claim 8 (depends on 2)

The surfactant-coated hemihydrate gypsum according to claim 2 which has a cumulative pore volume of not more than 0.5 mL/g.