Quartzite corundum refractory concretes

Abstract

Quartz refractory concretes arc successfully used to line steel-casting and pig-iron ladies [1][2][3]. %~e low thermal shock resistance of these concretes does not permit their use in other heat equipment, in spite of their excellent thermomechanical properties.In the zones of the ladle lining where an inadequate amount of quartz melt is formed, the concretes do not work satisfactorily, because of spaIlatton due to temperature differences.In order to increase the resistance of the lining of steel-casting ladles, to eliminate intermediate repairs to the upper rows of the lining, and to improve the thermomechanteal properties of quartzite-corundum concretes, compositions have been de~eloped for these materials and the technologies and applications determined [4]. N_ullite-siliceous, mullite, and mullite-corundum articles which show no shrinkage on firing are well known; these are synthesized by sintering the crock of a grainy quartzite and dispersed alumina which have excellent thermomechanical and slag resistant properties [5]. We have studied the possibility of using dispersed corundum recovered by wet dust-removal machinery and accumulated in the slurry deposits. The characteristics of the main raw materials for the manufacture of concretes are shown in Table 1.The compositions of the masses for the preparation of the concretes are given in Table 2.Specimens were obtained from the masses by pressing at 60 MPa, followed by drying at 120~The properties of the specimens are given in Table 3.The slag resistance of the concretes was determined by finding the area of the cross section of a crucible penetrated by slag at 1450~we studied the structure of the refractory-slag contact zone under a microscope.The orthophosphoric acid concretes had significant thermal-shock resistance (specimens Nos. 9-11) but low slag resistance. In all the phosphate-based specimens, the slag had penetrated totally into the refractory. The water-glass specimens were more resistant to slag penetration as a result of the formation of a viscous melt on the refractory-slag interface; this melt sealed up the pores by decreasing the surface of interaction between slag and refractory. The water-glass quartzite-corundum concretes were recommended for tests In the lining of the slag beIt of steel-casting ladles.In order to improve the grainy composition of the concrete masses, some experimental articles were pre-

High-alumina technogenic raw material

“…According to UkrNIIO data, the cost of ACC is three times lower than scarce and expensive technical grade alumina [26]. In 1983In -1984 in the Western Institute of Refractories as a result of comprehensive study of various technogenic raw materials work was performed on "Technical and economic evaluation (TEE) of use of industrial waste as raw material for producing refractory materials." On the basis of the TEE the required assortment and volume of production was determined for new highly effective objects and materials based on ACC.…”

“…The most significant volume of research in this area was carried out by the branch industries of the Ural region: UralNIIstromproekt [29], VoctIO [30], BashNIPIstrom [31], etc. In spite of the adequate scientific and technological level of the research, possibilities of using electrocorundum slag in manufacture from many forms of product, it has not been 90 V. A. Perepelitsyn et al found industrial scale application.…”