Use of unfired magnesia roof refractories

Abstract

We developed a technology and produced at the Panteleiminov Refractories Factory an experimental-industrial batch of unfired magnesite-chromite refractories in cladding with internal baffles (grids). These refractories can be used in the roofs of open-hearth furnaces with charges of up to 100 tons. The roof life is no shorter than with the use of ordinary fired magnesite-chromite bricks. The structure of the roofs can be built with the ordinary thrust-suspension system, but using asbestos inserts or board inserts for thermal-expansion compensation in the joints between the bricks in the rings. In heavy working conditions the wear intensity of unfired refractories in the open-hearth furnace roofs sharply increases. Unfired reinforced magnesite-chromite refractories can be successfully used in building the walls of the heads and vertical channels. It is necessary to test unfired reinforced magnesite-chromite refractories in the roofs of the lower structure of open-hearth furnaces. To increase the economic advantages of using unfired reinforced chromite refractories it will be necessary to reduce the costs of making the cladding.