Methods for producing stucco compositions useful in making gypsum products

Patent metadata

Field	Value
Publication number	US-2024246855-A1
Application number	US-202318515518-A
Country	US
Kind code	A1
Filing date	Nov 21, 2023
Priority date	Jan 22, 2023
Publication date	Jul 25, 2024
Grant date	—

Abstract

The present disclosure relates generally to methods for producing stucco compositions useful in making gypsum products. One aspect of the disclosure is a method for producing a stucco composition using dielectric calcination. Another aspect of the disclosure is a production process for a gypsum product using a stucco composition prepared by dielectric calcination.

First claim

We claim:

1 . A method of producing a stucco composition, the method comprising:
providing a calcium sulfate feed comprising calcium sulfate dihydrate (gypsum); and calcining the calcium sulfate feed using dielectric heating by exposing it to radio frequency radiation at a specific power of at least 15 W/kg calcium sulfate dihydrate in the feed (e.g., for a duration that applies a specific energy dose of at least 0.0027 kW-hr/kg of calcium sulfate dihydrate in the feed), in a radio frequency range up to 900 MHz.

2 . The method of claim 1 , wherein the calcium sulfate feed comprises at least 60 wt % gypsum.

3 . The method of claim 1 , wherein the calcium sulfate feed comprises free moisture, present in an amount up to 15 wt %.

4 . The method of claim 1 , wherein the radio frequency range is in the range of 1-1-500 MHz.

5 . The method of claim 1 , wherein the radio frequency range is in the range 20-100 MHz.

6 . The method of claim 1 , wherein the radio frequency range is in the range 30-50 MHz.

7 . The method of claim 1 , wherein the radio frequency range is in the range of 5-10 MHz.

8 . The method of claim 1 , wherein the specific power in the radio frequency range is at least 30 W/kg.

9 . The method of claim 1 , wherein the specific power in the radio frequency range is at least 200 W/kg.

10 . The method of claim 1 , wherein the calcium sulfate feed is exposed to a specific energy dose in the radio frequency range of at least 0.0027 kW·h/kg of calcium sulfate dihydrate in the feed.

11 . The method of claim 1 , wherein the calcium sulfate feed is exposed to a specific energy dose in the radio frequency range of at least 0.1 kW·h/kg of calcium sulfate dihydrate in the feed.

12 . The method of claim 1 , wherein the calcium sulfate feed is exposed to a specific energy dose in the radio frequency range of no more than 3 kW·h/kg of calcium sulfate dihydrate in the feed.

13 . The method of claim 1 , wherein at least 70 mol % of the calcium sulfate dihydrate of the calcium sulfate feed is converted to calcium sulfate hemihydrate.

14 . The method of claim 1 , wherein at least 5% of crystalline water is removed from the calcium sulfate dihydrate.

15 . The method of claim 1 , wherein at least 45% of crystalline water is removed from the calcium sulfate feed.

16 . The method of claim 1 , wherein no more than 75% of crystalline water is removed from the calcium sulfate feed %.

17 . The method of claim 1 , wherein the calcining reduces the mass of the calcium sulfate feed to provide a stucco composition having a mass of no more than 95% of the mass of the calcium sulfate feed.

18 . The method of claim 1 , wherein the calcining reduces the mass of the calcium sulfate feed to provide a stucco composition having a mass of no more than 85% of the mass of the calcium sulfate feed.

19 . The method of claim 1 , wherein the calcining reduces the mass of the calcium sulfate feed to provide a stucco composition having a mass in the range of 75-95% of the mass of the calcium sulfate feed.

20 . A production process for a gypsum product, the production process comprising:
providing a stucco composition by the method of claim 1 ; hydrating the stucco composition in an aqueous slurry; allowing the aqueous slurry to set; and drying the set slurry to form the gypsum product.

Assignees

• Certainteed Gypsum Inc
• Georgia Tech Res Inst

Inventors

• Goulet Remi L
• Lespiat Remi
• Keniar Khoudor
• Conforti Kameron Michael
• Garimella Srinivas
• Tjards Jacob
• Lockyear Kristian

Classifications

• C04B28/14

  containing calcium sulfate cements {(gypsum-paper plates E04C)} · CPC title

• C04B41/5307

  Removal of physically bonded water, e.g. drying of hardened concrete (E04B1/7007 takes precedence) · CPC title

• C04B11/005 Primary

  Preparing or treating the raw materials · CPC title

• C04B2111/0062

  Gypsum-paper board like materials · CPC title

• C04B11/028 Primary

  Devices therefor {characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained} · CPC title