Lightweight porous ceramic product prepn. - by calcining a ceramic contg. a pore former mixed with a glaze to improve strength

摘要

A light weight, porous, ceramic product in the form of a (non)-supporting construction element for building, insulation, ceramic filters, cooling bodies or drainage pipes with a pore dia. of 0.5-6.0 mm has a thin film of glaze on the walls of the. The elements have improved strength at the same degree of porosity as elements with no glazing layer, and the same strength with a higher degree of porosity. Compression strength may be improved by 300%. Building bricks may be prepd. having a higher degree of porosity and heat insulation while maintaining their usual strength. The thin film of glaze may be (dis)continuous and is esp. net-like. The elements are prepd. by mixing a raw ceramic compsn. with a vaporisable and/or pyrolysable particulate pore former (I) contg. a glazing compsn. (II) with a softening point lower than the calcining temp. of the ceramic, moulding and drying the compsn. and calcining. (I) may be a foamed resin e.g. polystyrene, polyurethane, wood flour, carbon powder, peat and/or cellulose (II) is pref. a ceramic frit, glass or a mineral such as K feldspar, nephelin-syenite or colemanite and is finely ground.