Fire-resistant calcium sulphate-based products

• US 10,662,113 B2
• Filed: 11/17/2015
• Issued: 05/26/2020
• Est. Priority Date: 11/21/2014
• Status: Active Grant

• Current Assignee: Saint-Gobain Placo
• Original Assignee: Saint-Gobain Placo
• Inventors: Brooks, Laura, Fisher, Robin, Rideout, Jan
• Primary Examiner(s): Green, Anthony J
• Application Number:
  US15/525,467
• Publication Number:
  US 20170334783A1
• Time in Patent Office: 1,652 Days
• CPC Class Codes: C04B 14/062 Microsilica, e.g. colloïdal silica preparing microsilica slurries or suspensions C04B18/148
• CPC Class Codes: C04B 14/08 Diatomaceous earth
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/14 Minerals of vulcanic origin granite C04B14/048
• CPC Class Codes: C04B 14/16 porous, e.g. pumice
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 18/101 Burned rice husks or other burned vegetable material
• CPC Class Codes: C04B 18/146 Silica fume
• CPC Class Codes: C04B 2111/28 Fire resistance, i.e. materials resistant to accidental fires or high temperatures
• CPC Class Codes: C04B 2111/34 Non-shrinking or non-cracking materials
• CPC Class Codes: C04B 22/08 Acids or salts thereof C04B22/0013 takes precedence
• CPC Class Codes: C04B 22/085 containing nitrogen in the anion, e.g. nitrites
• CPC Class Codes: C04B 24/42 Organo-silicon compounds
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

The present invention provides calcium sulphate-based product having reduced shrinkage after exposure to high temperatures, the product comprising gypsum, a pozzolan source (e.g. in an amount between 4-27 wt %) and a metal salt additive (in an amount between 0.5 and 10 wt %). The pozzolan source may be selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil. The metal salt additive may be a metal salt which decomposes between a temperature of 300-500° C. to yield a metal oxide, e.g. magnesium nitrate.

Claims

1. A gypsum wallboard comprising:

gypsum, a pozzolan source, and a metal salt, wherein;

the gypsum is provided in an amount of 40% or greater based on a total weight of the gypsum wallboard,

the metal salt is selected from nitrate and hydrogen carbonate salts of calcium, magnesium, copper, zinc, iron and aluminum, and carbonate and chloride salts of copper, zinc, iron or aluminum; and

the metal salt is provided in an amount of between 0.5 wt % and 10 wt % based on the weight of the gypsum, the pozzolan source and the metal salt.

2. The gypsum wallboard according to claim 1, wherein the pozzolan source is included in an amount between 4 wt % and 27 wt % (based on the weight of the gypsum, the pozzolan source and the metal salt).

3. The gypsum wallboard according to claim 1, wherein the wt % of pozzolan source and wt % metal salt are equal.

4. The gypsum wallboard according to claim 1, wherein the pozzolan source is selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil.

5. The gypsum wallboard according to claim 1, wherein the metal salt decomposes between a temperature of 300°

C.-500°

C. to yield a metal oxide.

6. The gypsum wallboard according to claim 1, wherein the metal salt is a magnesium salt.

7. A gypsum wallboard formed by a process comprising:

drying an aqueous slurry containing gypsum, a pozzolan source, and a metal salt additive, wherein;

the gypsum is provided in the gypsum wallboard in an amount of 40% or greater based on a total weight of the gypsum, the pozzolan source and the metal salt additive,

the metal salt additive is selected from nitrate and hydrogen carbonate salts of calcium, magnesium, copper, zinc, iron and aluminum and carbonate and chloride salts of copper, zinc, iron or aluminum, and

the metal salt additive is included in the slurry in an amount between 1 wt % and 15 wt %.

8. The gypsum wallboard according to claim 7, wherein the pozzolan source is included in the slurry in an amount between 5 wt % and 30 wt %.

9. A calcium sulphate-based composition for use in forming a gypsum wallboard by drying an aqueous slurry of the calcium sulphate-based composition, the calcium sulphate-based composition comprising:

gypsum, a pozzolan source, and a metal salt, wherein;

the gypsum is provided in the gypsum wallboard in an amount of 40% or greater based on a total weight of the gypsum wallboard,

the metal salt is selected from nitrate and hydrogen carbonate salts of calcium, magnesium, copper, zinc, iron and aluminum and carbonate and chloride salts of copper, zinc, iron or aluminum, and

the metal salt is included in the slurry in an amount between 1 wt % and 15 wt %.

10. The calcium sulphate-based composition according to claim 9, wherein the pozzolan source is included in an amount between 5 wt % and 30 wt %.

11. The calcium sulphate-based composition according to claim 9, wherein the wt % of pozzolan source and wt % metal salt are equal.

12. The calcium sulphate-based composition according to claim 9, wherein the pozzolan source is selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil.

13. The calcium sulphate-based composition according to claim 9, wherein the metal salt decomposes between a temperature of 300°

C.-500°

C. to yield a metal oxide.

14. The calcium sulphate-based composition according to claim 13, wherein the metal salt is a magnesium salt.

15. A method of forming a gypsum wallboard by drying an aqueous slurry comprising the composition according to claim 9.

16. A gypsum wallboard comprising:

gypsum, a pozzolan source, and a metal salt additive, wherein;

the gypsum is provided in an amount of 40% or greater based on a total weight of the gypsum wallboard,

the metal salt additive is selected from calcium nitrate and salts of magnesium, copper, zinc, or iron, and

the wt % of pozzolan source and wt % metal salt additive are equal.

17. The gypsum wallboard according to claim 16, wherein the pozzolan source is selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil.

18. The gypsum wallboard according to claim 16, wherein the metal salt decomposes between a temperature of 300-500°

C. to yield a metal oxide.

19. The gypsum wallboard according to claim 18, wherein the metal salt is a magnesium salt.