Microstructure and phase evolution of Indian magnesite‐derived MgAl2O4 as a function of stoichiometry and ZrO2 doping
Microstructure and phase evolution of Indian magnesite‐derived MgAl2O4 as a function of stoichiometry and ZrO2 doping
复制标题
印度菱镁矿衍生的 MgAl2O4 的微观结构和相演化随化学计量和 ZrO2 掺杂的变化
DOI：
10.1111/ijac.12759
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发表时间：
2018
影响因子：
2.1
通讯作者：
K. Das
中科院分区：
文献类型：
--
作者：
S. Mandal;S. Mondal;K. Das
为了帮助开发具有成本效益的烧结尖晶石作为耐火原料，本文提出了一个广泛的分析的微观结构和复杂的相演变的富铝，富镁，和化学计量的尖晶石骨料来自印度菱镁矿和煅烧氧化铝。在1650°C烧结时，富铝尖晶石中的孔形态发生转变，并形成嵌入多孔富铝尖晶石基质中的板条。在1600°C下烧结的化学计量的尖晶石主要由直接结合的角状等轴尖晶石晶粒组成，其在固溶体中掺入杂质。富镁尖晶石由棱角性降低的尖晶石晶粒沿着晶间无定形相、小的圆形钙镁橄榄石晶粒和方镁石组成。EDS线扫描显示，直接结合的尖晶石晶粒之间存在无杂质连接。含0.65wt%ZrO 2的富镁尖晶石形成沿着尖晶石晶界分布的ZrO 2-CaO-MgO立方固溶体，减少了晶间非晶相和钙镁橄榄石。这增加了尖晶石固溶体中SiO2和MgO的含量，引发了亚稳立方镁橄榄石的出溶，在XRD图谱中表现为分裂的尖晶石峰。一个14.7%的减少渣渗透表现出掺杂富镁尖晶石与0.21%的ZrO 2。化学计量和富镁尖晶石在1600°C下达到0.35%和0.54%的显气孔率，这优于大多数商业烧结耐火尖晶石。
To aid development of cost-effective sintered spinel as a refractory raw material, this paper presents an extensive analysis of microstructure and complex phase evolution of Al-rich, Mg-rich, and stoichiometric spinel aggregates derived from Indian magnesite and calcined alumina. Pore morphology in Al-rich spinel was transformed upon sintering at 1650°C and corundum laths embedded in porous Al-rich spinel matrix was formed. Stoichiometric spinel sintered at 1600°C consisted of mostly direct bonded angular equiaxed spinel grains which incorporated the impurities in solid solution. Mg-rich spinel was composed of spinel grains with reduced angularity along with intergranular amorphous phase, small round monticellite grains, and periclase. EDS line scan revealed impurity-free joins existed between direct bonded spinel grains. Mg-rich spinel containing 0.65 wt% ZrO2 formed cubic ZrO2-CaO-MgO solid solution located along spinel boundaries, which reduced both intergranular amorphous phase and monticellite. This increased SiO2 and MgO content in spinel solid solution triggering exsolution of metastable cubic forsterite manifested as split spinel peaks in XRD pattern. A 14.7% reduction in slag penetration was exhibited upon doping Mg-rich spinel with 0.21% ZrO2. Stoichiometric and Mg-rich spinels attained 0.35% and 0.54% apparent porosity at 1600°C, which is better than most commercial sintered refractory spinels.