Alpha-Type Calcium Sulfate Hemihydrate Compositions
AssigneeG.B. Technologies, LLC
InventorsDanny W. Cox, Robert B. Bruce
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Abstract
Disclosed is an improved alpha-type calcium sulfate hemihydrate. Methods of producing an improved powdered calcium sulfate hemihydrate (CaSO4.½H2O) [alpha-type] compound are disclosed, at least one method including forming calcium sulfate dihydrate (CaSO4.2H2O) into a briquette, calcining the briquette to transform the calcium sulfate dihydrate to calcium sulfate hemihydrate [alpha-type], drying the calcium sulfate hemihydrate [alpha-type] briquette, and optionally grinding the briquette. Also disclosed are methods of producing an improved gypsum plaster including producing the disclosed powdered calcium sulfate hemihydrate [alpha-type] and mixing the powdered calcium sulfate hemihydrate [alpha-type] with water.
Claims12
1-9. (canceled)
A ground alpha-hemihydrate made from a process comprising
- forming calcium sulfate dihydrate into a briquette having physically bound water in a range from about 15% to 21% by weight of the calcium sulfate dihydrate briquette, wherein forming calcium sulfate dihydrate into a briquette includes providing a pressure of formation greater than 14 megapascal to produce a substantially uncracked briquette that will remain substantially uncracked during calcination;
- adding free water to the calcium sulfate dihydrate briquette, wherein the free water is just greater than 0% up to about 12% by weight of the calcium sulfate dihydrate briquette;
- calcining the briquette;
- transforming the calcium sulfate dihydrate briquette to an alpha calcium sulfate hemihydrate briquette;
- and
- drying the alpha calcium sulfate hemihydrate briquette.
The product of claim 28, further comprising at least one of the following:
- sand and fly ash.
An alpha calcium sulfate hemihydrate comprising:
- crystals of the alpha calcium sulfate hemihydrate that have grown together to form clusters of the crystals;
- wherein the clusters of the crystals of alpha calcium sulfate hemihydrate have a substantially smaller amount of pore volume between the clusters, when compared to the pore volume of alpha calcium sulfate hemihydrate crystals formed from dihydrate briquettes with about 0% to 12% moisture concentration.
A dry, ground alpha calcium sulfate hemihydrate converted from a calcined calcium sulfate dihydrate briquette;
- wherein the dry, ground alpha-calcium sulfate hemihydrate has a water demand of less than 50 milliliters (ml) per 100 grams (g) of dry, ground alpha calcium sulfate hemihydrate.
Dependencies are inferred from the claim text.