Slag resistance of aluminosilicate compositions with additions of silicon carbide

Abstract

The reaction of refractory ladle materials with slag to a significant degree determines the life of the lining in steel-casting ladles, especially during intensification of the melting of steels with oxygen, and so an increase in the resistance of ladle refractories is an urgent problem [i]. One of the ways of solving it was to introduce carbon-containing materials into the refractory batches including silicon carbide.Data are available on the positive influence of additions of silicon carbide to the aluminosilicate lining iron-carrying [2] and periclass-foresterite-carbon lining for the nonslag belts of steelcasting [3] ladles.In the search for new compositions for refractories in factory laboratories, a crucible method of determining the slag resistance [4] has found extensive use. We present the results of a study of the reaction of ladle open-hearth slag with refractory compositions on the basis of chamotte containing additions of silicon carbide, obtained by the crucible method, and examined in the present article by the method of determining the rate of solution of the refractory material in the slag.The criteria for the slag resistance of the material were selected as the average linear and mass rate of solution of the refractory specimen in the slag at constant temperature. The laboratory equipment is illustrated Fig. i.The slag was melted and heated to the test temperature in an iron crucible placed in a carbon resistance furnace.The refractory specimen being studied was heated over the slag surface for 3 min in a holder made from molybdenum wire, and then submerged in the slag for the stated time (2 min).After extraction the specimen was brought into contact with a porous corundum insert which was used to remove the slag from the surface of the specimen on account of the capillary suction and wetting, and then the specimen was taken from the furnace and studied.The intensity of the solution of the refractory in the slag can be evaluated from the mass reduction and the change in the linear dimensions of the specimen.The mass of the specimen cylinders of diameter 17 and height 11-17 mm was 6-7 g, and the reduction in mass came within the range 0.5-4 g.The specimens taken from the slag had a cylindrical shape, and the amounts of reduction in their height and diameter were the same, i.e., the solutions occurred with the same linear velocity from the side and front surfaces of the cylinder.The reduction in mass during the test enabled us to assess the tendency of the refractory to be dissolved in the slag. For the analysis of the reaction of the refractory with the slag melt it is convenient to use the average linear rate of solution v, determined by the thickness of the layer of refractory dissolved in the slag per unit itme, or the average mass velocity of the solution v M, expressing the mass of the refractory dissolved per unit time from unit area of contact of refractory with slag.The determination of the thickness of the layer of material dissolved in the slag, according to the measurement of the di...