二氧化钛对菱镁矿风化石制备镁铝尖晶石组成结构的影响

Influence of Titanium Dioxide on Composition and Structure of Mg-Al Spinel Material Prepared from Decomposed Magnesite

以菱镁矿风化石与工业氧化铝为原料,按照尖晶石理论化学计量比对两种物料进行配料,添加不同量二氧化钛,研究二氧化钛对制备的镁铝尖晶石的组成、结构、结晶度、晶胞常数的影响,用XRD和SEM对烧后试样的相组成和显微结构进行研究。用X'pert plus软件计算相对结晶度,并分析镁铝尖晶石相的晶胞参数。结果表明:当二氧化钛添加量小于1.6 wt%时,结晶度随着二氧化钛加入量的增加而降低,主晶相镁铝尖晶石的晶胞参数却随之增大;当二氧化钛加入量为1.6～2.0%时,镁铝尖晶石对二氧化钛的置换固溶作用降低,镁铝尖晶石晶胞参数增加趋势有所减弱。一定量的二氧化钛有利于材料中镁铝尖晶石的生成,二氧化钛的最佳添加量为2.0%。

Mg-Al spinel was prepared using decomposed magnesite and industrial alumina as raw materials according to the theory ration of Mg-Al spinel.The effect of titanium dioxide on composition,cell parameters,crystalinity and microstructure of crystalline phases,microstructure of Mg-Al spinel was studied.XRD and SEM were used to characterize the crystalline phases and microstructures.The crystalinity and cell parameters were estimated by X＇Pert plus software.The experimental results showed that the Mg-Al spinel material could be prepared from decomposed magnesite and industrial alumina.The crystallinity of the obtained materials decreased with increasing titanium dioxide that was less than addition amount of 1.6%.The cell parameter and lattice volume of major phase Mg-Al spinel were increasing with titanium dioxide addition.The displacement interaction between titanium dioxide and Mg-Al spinel wear off when the titanium dioxide was 1.6%-2.0%,and the increasing trend of cell parameter weaked.The amount of titanium dioxide had helped to improve the formation of Mg-Al spinel in the materials,the optimum addition content of titanium dioxide was 2.0%.