Effect of Dense Layer Formation on Dissolution Rate of MgO-C Refractory in Molten Slag

Abstract

The corrosion test for magnesia-carbon refractory, MgO-C, with dense layer has been carried out by a rotating cylinder method at 1673 K. The specimen, which was a cylinder of 25 mm diameter and 25mm height, was rotated in molten slag at 50 rpm. The chemical composition of slag was CaO-SiO2-FeO-MgO-CaF2. The corrosion rate was determined by the variation of radius of the cylindrical specimen against corrosion time. The decrease of radius was obtained by a calculation of dissolved MgO into the slag. In addition, the diameter of the specimen was measured with a slide calipers after the corrosion test. The cylindrical specimen was heated to form a dense layer before the corrosion test. The corrosion rate of the MgO-C refractory with dense layer was slower than that of the MgO-C refractory without dense layer. The oxidized layer, where the dense layer formed, dissolved at much the same rate as the MgO brick. The dense layer probably obstructed contact between slag and carbon in the matrix, and then oxidation of C by slag did not take place. Formation of the dense layer was effective to inhibit corrosion of MgO-C refractory by molten slag.

High Corrosion Resistance of Alumina-Chrome Refractory

“…The cylindrical specimen for the corrosion test was prepared by being cut the shaped brick. The measurement of the corrosion rate was carried out in air at 1673 K by a rotating cylinder technique which was reported by Sunayama and other researchers previously (4). The corrosion rate was defined as the decrease of the diameter of the cylindrical specimen.…”

Corrosion Mechanism of Refractory Immersed in Molten Slag

“…That result implied that mass transfer from the MgO-C brick was accelerated by the movement of the CO bubbles generated from the chemical reaction [3]. 8 C refractory + (FeO) s = CO gas + Fe solid [3] The microstructure of the cross section after the corrosion test was shown in Fig. 3.…”

“…The movement of the bubbles through the boundary layer has rapidly increased the corrosion rate, and the existence of the chromium oxide suspension in the boundary layer has increased the resistance to corrosion. 8,9 There are a few data regarding the effect of the movement of the bubble on the corrosion rate, though the previous researchers has reported that the low Reynols number particle or the bubble dragged the solute. 10,11 In this study, the measurement of the corrosion rate was carried out by using the rotating cylinder to obtain the more precise information regarding the corrosion mechanism of the three types of the commercial bricks, and to obtain the deep understanding about the mechanism of corrosion under three conditions of the boundary layer.…”

Corrosion Mechanism of Refractory Immersed in Molten Slag

“…[1][2][3][4] The authors have founded that the movement of the bubbles through the boundary layer has rapidly increased the corrosion rate, and the existence of chromium oxide suspension in the boundary layer has increased the resistance to corrosion. 5,6 Recently, the development of new corrosion-resistant materials has been desired. In the present study, we present the deep understanding about the mechanism of corrosion under three conditions of the boundary layer.…”

“…The corrosion rate was determined by measurement of the decrease of the diameter of the cylindrical specimen. 2,5 Furthermore, EPMA analysis was carried out for the cross section of the specimen after the corrosion test. The materials for the specimen were magnesia-carbon of 5 mass % refractory, MgO-C, magnesia-chromium oxide, MgO-Cr 2 O 3 and naphthalene.…”