	US 12,281,045 B2
	Methods for reclaiming gypsum panels that contain hydrophobic materials and use thereof
Rudy A. Schermann, El Centro, CA (US); Annamaria Vilinska, Chicago, IL (US); Alfred Li, Naperville, IL (US); Blair C. Walker, Timmins (CA); Te Hua Lau, Glenview, IL (US); Stephen P. Erickson, Imperial, CA (US); Jose Luis Carrazco, Imperial, CA (US); and Angel Arturo Rueda, El Centro, CA (US)
Assigned to KNAUF GIPS KG, Iphofen (DE)
Filed by KNAUF GIPS KG, Iphofen (DE)
Filed on Mar. 24, 2021, as Appl. No. 17/210,789.
Claims priority of provisional application 63/016,540, filed on Apr. 28, 2020.
Prior Publication US 2021/0331978 A1, Oct. 28, 2021
Int. Cl. C04B 28/14 (2006.01); B28B 19/00 (2006.01); C04B 18/167 (2023.01); C04B 24/42 (2006.01); C04B 38/10 (2006.01); C04B 111/00 (2006.01)

CPC C04B 28/14 (2013.01) [B28B 19/0092 (2013.01); C04B 18/167 (2013.01); C04B 24/42 (2013.01); C04B 38/10 (2013.01); C04B 2111/0062 (2013.01)]

21 Claims

1. A method for making a gypsum board comprising:

depositing a core layer comprising an aqueous gypsum slurry over a forming surface;

wherein non-calcined reclaimed gypsum particles in the aqueous gypsum slurry consist of non-calcined reclaimed gypsum particles with a D50 particle size of about 200 μm to about 800 μm, and wherein the non-calcined reclaimed gypsum particles comprise at least about 50 wt. % calcium sulfate dihydrate and about 0.05 wt. % to about 10 wt. % hydrophobic material;

wherein the aqueous gypsum slurry is made by combining

water, and

the non-calcined reclaimed gypsum particles and

calcined gypsum particles comprising calcium sulfate hemihydrate; and

allowing the core layer to set, thereby forming a set gypsum core.