No abstract

Refractory concretes are used extensively to line steel teeming ladies. The concrete linings are made by monolithic tamping [1-3] and casting [4] methods. Cherubim and Peach [5] give comparative results for the preparation of linings by different procedures.The concretes used as the lining material are as follows: concrete with 95-99 ~# crystalline quartzite, 1-5% slag, and 16-18% slag (above 100% ~ water glass with a density of 1.3 g/cm ~ [61; concrete from quartzite with added clay [7,8]; and silica concrete with a chemical binder [9, 10].

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-