Production of porous gypsum moldings

US4040850A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hans Kyri · Cologne, DE
• Karl Brandle
• Martin Muller · Berlin, DE
• Heinrich Heine · Krefeld, DE

Key dates

• Filing date: Aug 14, 1975
• Grant date: Aug 9, 1977
• Expiry date: Aug 14, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B28/14
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

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.