引入Y_2O_3对刚玉-尖晶石中间包挡渣墙高温强度和抗渣性的影响

Influence of adding Y_2O_3 on HMOR and slag resistance of corundum-spinel tundish slag wall

以特级矾土、棕刚玉、电熔白刚玉、镁铝尖晶石、α-Al2O3微粉、ρ-Al2O3、铝酸钙水泥为主要原料,添加分散剂和钢纤维等外加剂,研究了加入Y2O3对刚玉-尖晶石质中间包挡渣墙高温性能和抗渣性能的影响。结果表明:随着Y2O3加入量的增加,试样的高温抗折强度增大,抗渣性能变好,当加入量为2%(w)时其高温强度和抗渣性能均最优。显微结构分析表明:Y2O3高温下与Al2O3反应生成Y3Al5O12高熔点相,活化了晶格,有效提高试样的致密度,Y2O3活性较大,高温下还能与材料中SiO2反应形成高温结合液相钇硅酸盐,从而将试样中的尖晶石、Al2O3等物质紧密结合在一起,使试样变得更加致密,可有效阻挡渣的渗透;随着Y2O3的引入,在渣蚀后试样的反应层和渗透层发现大量的片状CA6保护层,抑制了渣的进一步渗透,同时由于生成CA6消耗了渣中的CaO,大大提高了渣的黏度,降低了渣的渗透能力,使渣的渗透逐渐停止。

Corundum-spinel tundish slag wall specimens were prepared using special grade bauxite, brown corundum, fused white corundum, magnesium aluminate spinel, α-Al2O3 micropowder,p-Al2O3, calcium alu- minate cement as the main raw materials,adding dispersant and other additives like steel fibre. The effect of Y2O3 addition on hot properties and slag resistance of the specimens was studied. The results show that with Y2O3 addition increasing ,the specimens have higher hot strength and better slag resistance. When the Y2O3 addition is 2 mass% ,the specimen has the best hot strength and slag resistance. The microstructure analysis shows that at high temperatures Y2O3 reacts with Al2O3 forming high melting point phase Y3Al5O12, which activates the crystal lattice and enhances the density of the specimen effectively. Y2O3 is active and can form liquid yttrium silicate with silica at high temperatures, bonding spinel and Al2O3 in the material tightly,and preventing the further slag penetration. As the addition of Y2O3 increases, abundant CA6 protection layers are observed at the reaction layer and the penetration layer, restraining the further penetration of slag. Meanwhile,the formed CA6 consumes CaO in the slag,enhancing the slag viscosity and lowering the penetration ability of the slag ,and thus stopped slag penetration gradually.