Method for producing calcium compounds containing water of crystallization

US6814947B1 · kind B1 · utility

Assignee

• Rethmann Lippewerk GmbH · DE

Inventors

• Josef Lehmkuhl · Haltern am See, DE
• Ansgar Fendel · Dortmund, DE
• Hubert Bings · Grafenau, DE

Key dates

• Filing date: Nov 29, 2001
• Grant date: Nov 9, 2004
• Expiry date: Nov 29, 2021

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21H19/385
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to the production of calcium compounds containing water of crystallization by means of a chemical reaction between an aqueous alkaline sodium aluminate solution and solid or dissolved or suspended calcium (hydr)-oxide in the presence of carbon dioxide or carbonate; and to the use of these compounds. The resulting precipitate is separated by sedimentation, dehydration, drying and/or clacination and/or grinding or suspending the resulting filter cake and reacted with at least one mineral acid and/or at least one salt of the same. The resulting precipitate, which contains water of crystallization, is separated by sedimentation, dehydration, drying and/or grinding.The resulting compounds can be used as fillers or as extra white pigments for producing and surface-treating paper, cardboard or card, for producing paints and lacquers, as a flame-retardant filler for fire-protecting construction materials and as a filler for producing plasterboards or building slabs or as a hydraulically active additive for producing expansive cements, expansive plasters and screeds and as a swelling component for explosion-protected explosives.