Method and apparatus for producing a multilayer cementitious product
AssigneeBPB Limited
InventorsWinfried Johannes Spickemann, Kane Ironside
Life of this patent
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Abstract
Gypsum plasterboard is produced by combining calium sulphate hemihydrate (stucco) with water to form an aqueous slurry. Uncalcined gypsum having a specific surface area below 0.3 m2/g is added to the slurry and the slurry is discharged onto a support so as to form a sheet of gypsum plasterboard.
Claims22
A method of preparing gypsum board comprising the steps of;
- a) combining calcium sulphate hemihydrate (stucco) with water to form an aqueous slurry,
- b) adding uncalcined gypsum to said slurry,
- b) discharging the slurry onto a support so as to form a sheet of gypsum board wherein said uncalcined gypsum has a specific surface area below 0.3 m2/g and has a particle size distribution within the range of 0.1 to 1000 microns.
A method of preparing gypsum wallboard as claimed in any one of the preceding claims wherein the uncalcined gypsum is present within the range of 5 to 50% weight on weight (w:w) of the calcium sulphate hemihydrate.
(canceled)
A method of preparing gypsum wallboard as claimed in any one of the preceding claims wherein the uncalcined gypsum is synthetic gypsum.
A method according to any one of the preceding claims wherein existing gypsum wallboard is crushed to a suitable size and added to the slurry to provide additional bulk to the wallboard mixture.
A cementitious composition comprising a mixture of stucco, water and desulphurisation gypsum wherein the specific surface area of at least some of the desulphurisation gypsum is below 0.3 m2/g and has a particle size distribution within the range of 0.1 to 1000 microns.
(canceled)
Dependencies are inferred from the claim text.