Method of treating produced gypsum

US5169617A · kind A · utility

Assignee

• Ruedersdorfer Zement GmbH · DE

Inventors

• Paul Clemens · Amsterdam, NL
• Ellen Wanzura · Hilpoltstein, DE
• Guenter Fietsch · Dessau, DE
• Helmut Meyer · Hilden, DE
• Detlef Kunze · Sandersdorf, DE
• Hans-Juergen Hartmann · Dessau, DE
• Wolfgang Schnelle · Dessau, DE

Key dates

• Filing date: Feb 12, 1991
• Grant date: Dec 8, 1992
• Expiry date: Feb 12, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02W30/91
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method for treating produced gypsum and, in particular, a method for treating flue-gas desulfurization gypsum forms highly active, modifiable gypsum binders of high strength with simultaneously drying, deagglomerating and dehydrating. Pursuant to the invention, produced gypsum (flue-gas desulfurization gypsum), with a particle size ranging up to 200 .mu.m, to which 10% by weight of milled natural gypsum is optionally added, is dehydrated at a material temperature of 335.degree. to 363.degree. K. and at a pressure ranging from 2.5 to 8 kpa, the dehydration being concluded when anhydrite III constitutes 50% to 100% by weight.