The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 08, 1994
Filed:
Sep. 27, 1991
Timothy J Roth, Allentown, PA (US);
Carmine R Gagliardi, Emmaus, PA (US);
William R Welliver, Ship Bottom, NJ (US);
Air Products and Chemicals, Inc., Allentown, PA (US);
Abstract
This invention relates to an improved process for producing gypsum calcium sulfate dihydrate flakes from powdered gypsum calcium sulfate dihydrate obtained from the desulfurization of flue gas by the wet limestone process. The flakes have sufficient size and strength such that the gypsum calcium sulfate dihydrate can be handled and processed in conventional equipment commonly used by wallboard manufacturers and others in the construction industry, The intermediate calcium sulfate dihydrate from the desulfurization process is dewatered to about 5 to 12% by weight and then compressed into a thin sheet under a compaction or compression load of 4 tons force to 15 tons force per linear inch of sheet width. A linear speed of from 0.5 to 2.5 feet per second is maintained during compaction providing a compaction residence time of from about 0.2 to 1.2 seconds. An elevated temperature is maintained during the compaction process to enhance the reformation of the crystal size and shape of the gypsum calcium sulfate dihydrate. The combination of pressure and temperature on the moist gypsum calcium sulfate dihydrate alters the physical characteristics of the gypsum calcium sulfate dihydrate, thereby resulting a sheet which breaks into hard flakes on exit from the compaction zone.