PRODUCTION OF TILE COMPRISING COAL AS MAIN RAW MATERIAL

摘要

PURPOSE:To obtain tiles free from occurrence of circular coloring extremely damaging good appearance by specifying at least a primary burning condition of molded article of raw material. CONSTITUTION:A tile raw material consisting essentially of coal ash is molded into a given shape, the molded articles are primarily burnt, then the surface of the primarily burnt molded articles is glazed and secondarily burnt to give tiles. In this method, a roller hearth kiln is used and the primary burning is carried out in a state (piled state not in layers) of the surface of the molded article exposed to an atmosphere in the furnace. Coal ash having components well resembling those of agalmatolite can be used as the coal ash. By using the coal ash and agalmatolite, contraction during tile burning can be suppressed.