RH精炼炉用MgO-MgAl2O4-Al复合材料的抗侵蚀性能研究

Study on corrosion resistance of MgO-MgAl2O4-Al composite materials of RH refining furnace

RH精炼炉用耐火材料无铬化进程中,镁铝尖晶石不烧砖经试验检验为电熔再结合镁铬砖的最佳替代产品。通过静态坩埚法对MgO-MgAl2O4-Al复合材料进行抗渣试验,与RH精炼炉用后的残砖进行对比分析,发现抗渣试验后的坩埚与RH精炼炉用后的残砖均形成了渣层、侵蚀层和原砖层。通过扫描电镜观察分别对残砖上渣层、侵蚀层和原砖层微观结构进行分析,发现MgO-MgAl2O4-Al复合材料在实验室条件下抗渣试验坩埚微观结构和现场使用后的残砖微观结构有着明显的不同。在RH精炼炉用后的残砖上形成了渣层、侵蚀层和原砖层,在渣层主要是方镁石、镁铝尖晶石和氧化铁固溶体以及铝酸钙相;在侵蚀层形成了致密方镁石带;通过对RH精炼炉现场使用后的残砖微观结构分析发现,金属铝粉能与MgAl2O4和MgO等形成Mg-A1-(Si)-O-N系非氧化物,从而提高材料的抗渣能力。MgO-MgAl2O4-Al复合材料在RH炉下部槽、浸渍管、环流管等高温部位具有良好的抗渣侵蚀性能。

In the development of chrome free process of refractory materials used for RH refining furnace,magnesium aluminum spinel non-fired bricks have been tested as the best alternative products for electrofusion and recombination of magnesium chromium bricks. Through static crucible test,the slag resistance experiment is carried out on the Mg O-MgAl2O4-Al composite material and the residual bricks used in the RH furnace are compared and analyzed. It is found that the slag layer,the erosion layer and the original brick layer form both in the crucible and the residual brick of the RH furnace during the slag resistance test. The microstructures of the slag layer,the erosion layer and the original brick layer are analyzed by scanning electron microscope. It is found that the microstructure of the crucible in slag resistance test under laboratory conditions is different from that of the residual brick on site. The results show that firstly the slag layer,the erosion layer and the original brick layer form in the residual brick used in RH furnace,and the phases in the slag layer are mainly periclase,magnesium aluminum spinel,iron oxide solid solution and calcium aluminate phase,secondly a dense periclase zone forms in the erosion layer,thirdly Mg-A1-(Si)-O-N non-oxide forms by the reaction of aluminium powder with MgAl2O4 and MgO,which is analyzed on residual bricks used in the RH furnace and improves the slag resistance. The MgO-MgAl2O4-Al composite has a good anti-slag resistance in the hot parts such as RH furnace trough,impregnated pipe and circulation pipe.