GB196342A - Process of utilisation of igneous rocks for the manufacture of ceramic products - Google Patents

Abstract

196,342. Bacchiolelli, M., and Devals, A. Meifred-. Jan. 14, 1922. Materials, special, for bricks and tiles; pottery materials.-Igneous rocks such as lava, basalt, dolerite, greenstone, &c. for, use in pottery and making bricks and tiles are crushed to powder and agglomerated under the influence of heat with or without the addition of impoverishing substances such as chamotte, quartzite, sand, &c. or fluxes) at a temperature lower than their own melting points. The rock may be crushed with impoverishing materials and water added to form a paste. It is then shaped by any known process either in the mould with or without pressure or in the lathe or by pouring in the state of slip in an absorbing mould. After being finally fashioned, it is dried and fired at the required temperature. In another process, a mould of refractory earth is prepared and the powdered rock either dry, as a paste, or in the form of slip is introduced into the mould, dried if drying is necessary and fired during the necessary time at a suitable temperature. The mould and the article are subsequently subjected to a slow cooling and the article is removed, which is facilitated owing to the difference of shrinkages of the mould and article. The articles may receive. a varnishing or natural glazing by simply melting of thin surfaces or they may be enamelled or varnished by any known process.