GB417166A - Improvements in and relating to the firing of ceramic goods - Google Patents

Abstract

417,166. Porcelain ware. POLLAK, J. E., 20, Holborn, London.-(Porzellanfabrik Kahla; Kahla, Thuringia, Germany.) Dec. 9, 1933, No. 34701. [Class 87 (i).] Porcelain and other sintered ceramic materials to be vitrified above the decomposition point of iron oxide, are fired in an electric furnace into which carbon monoxide is introduced at temperatures above 950‹ C. as the only reducing gas to prevent the deposition of carbon on the goods. The carbon monoxide may be mixed with carbon dioxide, and if desired diluted with nitrogen. Perfumes or pungent materials may be added to the monoxide for safety. Examples are 97 per cent nitrogen, 2 per cent carbon monoxide, and 1 per cent carbon dioxide ; and 85 per cent nitrogen, 10 per cent carbon monoxide, and 5 per cent carbon dioxide. Nitrogen may be used with the monoxide alone. For firing at very high temperatures carbon dioxide alone or mixed with nitrogen may be used in the first place as a protective gas for the electric heating elements, the monoxide being employed in the highest ranges. The monoxide is introduced at the end of the sharp firing zone and passes in the opposite direction to the goods up to the commencement of the zone, thence is directed back to the end of the zone.