Abstract: A method for primarily pre-heating ceramic material primarily in metallurgical processes, the material, in the form of brick or the like, forming part of a lining (3) or the like and being intended to be brought into contact with molten metal, such as molten steel, or a like melt, either directly or indirectly. Heating is effected primarily to reduce the magnitude of the temperature changes that occur in the material as a result of the alternating presence and absence of molten metal, or of a like melt that has an effect on the material.The method is particularly characterized in that heating is effected with the aid of so-called microwaves, and in that the cavity required herefor is formed by an existing metallic casing (2), preferably a steel casing, together with requisite auxiliary casing devices (4), such as lid devices (4) around the material. At least one microwave generator (7) is connected to the cavity.The invention also relates to an arrangement for carrying out the method.

Abstract: A method for heating primarily a so-called nozzle (2) through which a hot medium (10) in a liquid phase or in a liquid phase like condition, such as a molten metal, e.g. molten steel, is intended to pass in conjunction with a casting or molding operation for example.The method is particularly characterized in that the nozzle (2) is pre-heated prior to being brought into contact with the medium (10) and/or is heated at least periodically while medium is passing through the nozzle. Heating of the nozzle is effected with the aid of microwaves and the nozzle includes material which exhibits a significant loss factor with regard to microwaves. The nozzle is heated preferably for the purpose of avoiding blockages and the like from occurring in the nozzle as a result of a temperature decrease in the medium passing therethrough.The invention also relates to apparatus for carrying out the method.