Abstract: A gas injection stone is manufactured by embedding in a refractory compound a plurality of adjacent and abutting nets. Thereby, when the refractory compound is solidified and when the nets subsequently are removed by burning or melting, the result will be the formation within the stone of plural interconnected layers of interlinked gas channels.

Abstract: A gas flushing apparatus for use with a metallurgical vessel is disclosed which is operable to allow for adjustment of the flow rate of gas through the gas flushing apparatus into molten metal contained in the metallurgical vessel. Such adjustability is provided according to the invention by providing at least a pair of discrete gas-permeable portions extending through the gas flushing apparatus from a bottom end thereof to a top end thereof. The discrete gas-permeable portions are individually connected to a gas supply by a gas distribution mechanism. The gas distribution mechanism is operable to distribute gas from a supply line to either or both of the at least two discrete gas-permeable portions of the gas flushing apparatus. The gas-permeable portions can be formed with cross sections which differ in shape from the lower portions of the gas-permeable portions to the upper portions thereof. Also, the two discrete gas-permeable portions can be provided with differing cross sectional areas.

Abstract: Very thin plates of ceramic material with low binding strength are difficult to manufacture, since the stability of the moldings is very low, so that they can hardly be fed to a subsequent treatment stage after shaping. Therefore, after the ceramic material is molded into plate-shaped moldings, these moldings are pushed onto a flat carrier in the plane of their plate surface and are heated on it for a few minutes, so that iron sulfates form, which impart dimensional stability to the moldings.

Abstract: A refractory ceramic sink includes a frusto-conically shaped internal ceramic element having upper and lower end surfaces and an outer surface extending between the upper and lower end surfaces, and an external ceramic element encompassing the internal ceramic element and having upper and lower end surfaces and an inner surface extending between the upper and lower end surfaces and shaped complementary to the outer surface of the internal ceramic element. Channels are formed directly in at least one of the inner surface of the external ceramic element and the outer surface of the internal ceramic element, the channels extending from the bottom to the top of the sink.

Abstract: A composite refractory member includes at least one insert formed of an oxide ceramic material having a high resistance to molten material. The insert defines a discharge opening or other molten material contacting surface. A base structure encloses and supports the insert and is formed by molding a chemically setting refractory concrete including a refractory granulate of low-iron sintered magnesia with a MgO content of over 80 weight percent. Mold cores extend into the refractory concrete during molding such that the molded structure has expansion joints which later are filled with mortar.