Gypsum set accelerator and method of making the same
AssigneeNational Gypsum Company
InventorsFrank H. Campbell, Robert J. Piasecki, Larry W. Kingston, Edward A. Burkard
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Abstract
A composition for accelerating the setting reaction of an aqueous calcined gypsum slurry, and a method of making the same are disclosed. The composition includes a vibratory ball milled mixture of calcium sulfate dihydrate and a surfactant. The composition is prepared by subjecting the mixture to the high-frequency, low-impact grinding action of a vibratory ball mill. The resultant composition has a potency superior to that of conventional gypsum set accelerators.
Claims27
A composition for accelerating the setting reaction of calcium sulfate hemihydrate and water, the composition comprising a finely-ground product of a vibratory ball milling of a mixture comprising calcium sulfate dihydrate and a surfactant.
A continuous method of making a gypsum set accelerator, the method comprising the steps of:
- (a) substantially continuously blending calcium sulfate dihydrate and a surfactant to form a mixture;
- (b) conveying the mixture of step (a) into a vibratory ball mill;
- and,
- (c) milling the mixture in the mill at a temperature of less than about 50° C. to achieve a finely-ground gypsum set accelerator.
A gypsum set accelerator made by a method comprising the steps of:
- (a) substantially continuously blending calcium sulfate dihydrate and a surfactant to form a mixture;
- (b) conveying the mixture of step (a) into a vibratory ball mill;
- and,
- (c) milling the mixture in the mill at a temperature of less than about 50° C. to achieve a finely-ground gypsum set accelerator.
A composition for accelerating the setting reaction of calcium sulfate hemihydrate and water, the composition comprising a ground product of a vibratory ball milling of a mixture comprising calcium sulfate dihydrate and a surfactant, the composition having a potency allowing a gypsum slurry set time of about 3.1 minutes or less as determined by a ¼-pound Gillmore Needle Test (ASTM C266).
A composition for accelerating the setting reaction of calcium sulfate hemihydrate and water, the composition comprising a mixture comprising calcium sulfate dihydrate and a surfactant, the composition having a potency allowing a gypsum slurry set time of about 5.5 minutes or less as determined by a 1-pound Gillmore Needle Test (ASTM C266).
Dependencies are inferred from the claim text.