Bayer Aktiengesellschaft

Martin Muller

Karl Brandle

Heinrich Heine

Gerhard Winter

Friedrich Hinsche

Hans Kyri

In the production of a gypsum-based porous body of high strength by foaming a gypsum-water mixture containing alkali, hydrogen peroxide and a decomposition catalyst therefor, the improvement which comprises including in said mixture an acid-reacting compound with active hydrogen atoms in a quantity insufficient for complete neutralization of the alkali. The alkali is preferably calcium and/or magnesium oxide and/or hydroxide and the preferred acid-reacting compounds are phosphates and/or sulfates, especially potassium hydrogen phosphates. The acid-reacting compound is employed in an amount sufficient to neutralize about 5 to 50% of the alkali, the final pH being about 12 to 12.5.

Production of foamed gypsum moldings

In the production of a gypsum-based porous body of high strength by foaming a gypsum-water mixture, the improvement which comprises including in said mixture about 0.1 to 1 part of a water-soluble aluminum compound per 100 parts by weight of gypsum, calcium oxide or calcium hydroxide in such a quantity that the final mixture has a pH-value in the range of about 10 to 13, a decomposition catalyst, and about 0.5 to 5 parts of hydrogen peroxide, expressed as a 35% solution, per 100 parts by weight of mixture, the ratio of solids to liquid being about 1 : 0.4 - 1. The preferred aluminum compound is aluminum nitrate. The preferred decomposition catalysts are manganese compounds such as manganates or permanganates, e.g. potassium permanganate.

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Krefeld, Germany

Martin Muller