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Abstract

To prepare a ceramic molded article based on silicate or based on alumina, a ceramic starting material containing clay, kaolin, steatite and/or alumina is mixed with a silicate-containing flux, the mixture is made into a molded article and the molded article is heated and dense-sintered. At least some of the flux used is composed of a preferably alkali metal-free glass frit whose beginning of softening is above 850.degree. C. Advantageously, an alkali metal-free boron silicate glass is used in amounts of 0.1-20% by weight of the starting mixture. This process makes it possible to prepare, inter alia, ceramic molded articles comprising a glass phase and a crystalline portion substantially containing Al.sub.2 O.sub.3, in which the glass phase content is 22-34% by weight and comprises 50-68% by weight of SiO.sub.2, 12-22% of Al.sub.2 O.sub.3, 0.1-4.5% of Fe.sub.2 O.sub.3, 0.1-13% of TiO.sub.2, 0.1-23% of CaO, 0.1-9% of MgO, 0-7% of Na.sub.2 O, 0-11% of K.sub.2 O, 0-9% of BaO and 0-23% of B.sub.2 O.sub.3 and the crystalline portion comprises 1-25% of SiO.sub.2, 70-80% of Al.sub.2 O.sub.3, 0.1-1% of Fe.sub.2 O.sub.3, 0.1-3% of TiO.sub.2, 0.1-5% of CaO, 0.1-2% of MgO, 0-1.5% of Na.sub.2 O, 0-2.5% of K.sub.2 O, 0-2% of Bao and 0-5% of B.sub.2 O.sub.3.

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First Claim