PROCESS FOR THE MANUFACTURE OF TERRACOTTA TEXTILE OBJECTS, FREE OF FLOWERING, IN PARTICULAR BRICKWARE AND TILER PRODUCTS AND TERRACOTTA PRODUCTS MANUFACTURED BY THIS PROCESS

摘要

Clayware with a porous body, in which the SO3 content of the body is at least 0.04 per cent by weight, relative to the weight of the dry fired body, and whose body is free of unconverted calcium oxide, and which clayware does not show any undesired calcium hydroxide efflorescence even under prolonged action of moisture, is produced by adding, immediately before forming, a sufficient quantity of an iron sulphide, especially pyrite, which is oxidised with formation of SO2 and/or SO3 at approximately the firing temperature of the clay material, to the clay material present as a plasticised raw mass and homogeneously distributing it therein. By means of this process, it is possible to overcome in a simple manner the difficulties which arise in the firing of clayware in gas-fired furnaces and to obtain clayware which is free of the undesired calcium hydroxide efflorescences which adversely affect the fired colour and the adhesion of plaster, which is of paramount importance in particular for brickworks products.