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:
Sep. 15, 2009
Filed:
Sep. 20, 2006
Michael R. Lynn, Arlington Heights, IL (US);
W. David Song, Gurnee, IL (US);
Qingxia Liu, Vernon Hills, IL (US);
Qiang Yu, Grayslake, IL (US);
Michael L. Cloud, Canton, OK (US);
Michael R. Lynn, Arlington Heights, IL (US);
W. David Song, Gurnee, IL (US);
Qingxia Liu, Vernon Hills, IL (US);
Qiang Yu, Grayslake, IL (US);
Michael L. Cloud, Canton, OK (US);
United States Gypsum Company, Chicago, IL (US);
Abstract
A process is disclosed for making a blend of alpha- and beta-stucco including a slurry calcination step to produce alpha calcium sulfate hemihydrate followed by a fluidized bed calcination step to produce beta calcium sulfate hemihydrate. The process starts with 50-75% gypsum-containing solids slurry, and then steam calcines the slurry in a first reactor to form partially calcined gypsum slurry which contains calcium sulfate dihydrate and alpha calcium sulfate hemihydrate. The partially calcined slurry is then dewatered. Then the filter cake is fed into a kettle to complete the calcination process by converting the calcium sulfate dihydrate of the filter cake material into beta calcium sulfate hemihydrate.