Two-step sintering of magnesium aluminate spinels and their corrosion in Na_3AlF_6-AlF_3-CaF_2-Al_2O_3 bath  

两步烧结法制备镁铝尖晶石及其在Na_3AlF_6-AlF_3-CaF_2-Al_2O_3电解质中的腐蚀（英文）

作　　者：刘建华[1] 吕晓军[1] 李劼[1] 胡凌云[1] 蒋良兴[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第10期2754-2761,共8页中国有色金属学报（英文版）

基　　金：Project(51374240)supported by the National Natural Science Foundation of China;Project(2012BAE08B02)supported by the National Science and Technology Pillar Program of China

摘　　要：New types of refractory materials need to be developed for designing the man-made ledge of the Hall-Heroult cell for aluminum electrolysis, which are currently constructed by frozen ledge.Magnesium aluminate spinel （MAS） as potential candidate materials was prepared by two-step sintering. The densification and grain growth of the MAS wereinvestigatedbytheArchimedes drainage method and scanning electron microscope （SEM）. All the specimens were corroded in aNa3AlF6-AlF3-CaF2-Al2O3bath to assess the corrosion resistance. The results show that a MAS material with a high relative density of 99.2% and ahomogeneous microstructure is achieved under two-step sintering conditions. The corrosion mechanisms of MAS inNa3AlF6-AlF3-CaF2-Al2O3 bathare mainly proposed by dissolution of MAS, formation of aluminum oxide, and diffusion of fluorides. The MAS prepared by two-step sintering exhibits good corrosion resistance to theNa3AlF6-AlF3-CaF2-Al2O3bath.霍尔-埃鲁特铝电解槽需要一种新型的耐火材料来取代现有的凝固电解质构筑的炉帮。用两步烧结法制备的镁铝尖晶石作为潜在的候选材料,采用阿基米德排水法和扫描电镜研究镁铝尖晶石的致密化和晶粒长大。将所制备的试样在Na_3AlF_6-AlF_3-CaF_2-Al_2O_3电解质中腐蚀以评价其耐蚀性能。结果表明,用两步烧结法可制备高致密度(99.2%)和均匀显微结构的镁铝尖晶石。镁铝尖晶石对Na_3AlF_6-AlF_3-CaF_2-Al_2O_3电解质的腐蚀机理主要是镁铝尖晶石的溶解、氧化铝的形成和氟化物的扩散。两步烧结法制备的镁铝尖晶石具有良好的耐Na_3AlF_6-AlF_3-CaF_2-Al_2O_3电解质腐蚀性能。

关 键 词：magnesium aluminate spinel SINTERING aluminum electrolysis corrosion resistance 

分 类 号：TF351[冶金工程—冶金机械及自动化] TQ175.713.3[化学工程—硅酸盐工业]