摘要
在粒度≤0.6 mm的低品位菱镁矿粉中添加不同量的La2O3,使La2O3占二者的质量分数分别为0、1%、2%、3%、4%。经球磨混合,过100目(≤0.154 mm)筛,以聚乙烯醇为结合剂成型,110℃烘干后,在1550℃保温3 h烧成,然后检测试样的烧后收缩率、体积密度和显气孔率,并进行XRD和SEM分析。结果表明:在菱镁矿中添加La2O3,可以在方镁石中产生阳离子空位,形成缺陷结构,促进菱镁矿烧结。La2O3添加量为3%(w)时,试样的体积密度为3.25 g·cm^-3,显气孔率为12.7%。La2O3能与菱镁矿中的CaO和SiO2反应生成硅酸钙镧,并呈树枝状交错分布在MgO晶界处,减少了CaO和SiO2形成低熔点相钙镁橄榄石的可能性。
La2O3 with different additions(0,1%,2%,3%and 4%,by mass)was added into low grade magnesite powder with particle size≤0.6 mm.After ball milling and mixing,the mixture was passed through 100 mesh(≤0.154 mm)sieve and shaped with the polyvinyl alcohol as the binder,then baked at 110℃and then fired at 1550℃for 3 h.The fired samples were characterized in terms of the shrinkage,the bulk density and the apparent porosity,and were analyzed by an X-ray difftometer and a scanning electron microscope.The results show that the addition of La2O3 results in the generation of cation vacancies in periclase and defect structure,so as to promote the magnesite sintering.With 3%La2O3,the bulk density of the sample is 3.25 g·cm-3,and the apparent porosity is 12.7%.La2O3 can react with CaO and SiO2 in the magnesite to form calcium lanthanum silicate,which distributes in a dendritic shape at the MgO grain boundaries and thus reduces the possibility of CaO and SiO2 to form monticellite with low melting points.
作者
崔妍
刘新
曲殿利
Cui Yan;Liu Xin;Qu Dianli(School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,Liaoning,China)
出处
《耐火材料》
CAS
北大核心
2020年第5期441-443,共3页
Refractories
基金
辽宁省教育厅基础研究项目(2019LNJC04)。
关键词
菱镁矿
LA2O3
烧结镁砂
烧结性能
显微结构
magnesite
lanthana
sintered magnesia
sintering performance
microstructure
