精炼钢包用Al_2O_3-MgO-CaO系复相耐火材料的研发

为适应精炼钢包用耐火材料轻量化的发展需要,采用两步烧结法向Al_2O_3-MgO-CaO系复相耐火材料中添加La_2O_3,并对该耐火材料的抗LF精炼渣侵蚀性能进行了研究。结果表明,添加的La_2O_3优先固溶入Al_2O_3-MgO-CaO系复相耐火材料的晶相CaO·6Al_2O_3中,促使CaO·6Al_2O_3晶胞产生晶格畸变,有效抑制了CaO·6Al_2O_3晶粒沿基面的异常长大,进而有效地促进了Al_2O_3-MgO-CaO系复相耐火材料的烧结致密化。当添加La_2O_3的质量分数为4%,在1600℃保温2h烧成后,试样的气孔率由占总体积分数的19.2%下降至6.1%,体积密度由2.78g/cm3上升至3.18g/cm3,制得了含MgO·Al_2O_3、CaO·2Al_2O_3、CaO·6Al_2O_3晶相且呈现交织分布、显微结构致密的Al_2O_3-MgO-CaO系复相耐火材料,其抗LF精炼渣侵蚀性能与同等致密度的Al_2O_3-MgO质耐火材料相当。

Development of Al2O3-MgO-CaO refractories for refining ladle

In order to adapt the demands of refining ladle with the lightweight refractories, La2O3- doped Al2O3- MgO- CaO refractories were prepared by two- stage sintering method, and corrosion resistance of Al2O3- MgO- CaO refractories to LF refining slag was discussed. The results show that La2O3 preferentially dissolves to CaO??6Al2O3 phases in Al2O3- MgO- CaO refractory with complex phases, causing the lattice distortion of CaO??6Al2O3 crystal cells. Then the abnormal grain growth of CaO??6Al2O3 is controlled, and the densification of Al2O3- MgO- CaO refractories is effectively promoted. As a result, the apparent porosity decreases from 19??2vol% to 6??1vol% and the bulk density increases from 2??78g/cm3 to 3??18g/cm3 after heating at 1600?? for 2h by addition of 4mass% La2O3, then a kind of Al2O3- MgO- CaO refractory, which is comprised of MgO??Al2O3, CaO??2Al2O3 and CaO??6Al2O3 phases, with crystal intertwined distribution and dense microstructures is produced. Corrosion resistance of La2O3- doped Al2O3- MgO- CaO refractories to the LF refining slag is similar to that of Al2O3- MgO refractories with the same density.