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AssigneeRuedersdorfer Zement GmbH
InventorsPaul Clemens, Ellen Wanzura, Guenter Fietsch, Helmut Meyer, Detlef Kunze, Hans-Juergen Hartmann, Wolfgang Schnelle
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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.
A method for treating flue-gas desulfurization gypsum, comprising dehydrating said gypsum having a particle size of less than 200 .mu.m in a fluidized bed to form a calcium sulfate binder, said dehydrating including conducting dehydration at a reduced pressure ranging from 2.5 to 8 kpa and at a material temperature ranging from 333.degree. to 363.degree. K., and ending said dehydration when anhydrite III is present in said calcium sulfate binder in an amount ranging from 50% to 100% by weight of total dehydration product to provide a calcium sulfate binder rich in anhydrite III.
Dependencies are inferred from the claim text.