低品位菱镁矿与工业铝灰制备镁铝尖晶石

Preparation of magnesium aluminate spinel from low-grade magnesite and industrial alumina ash

以低品位菱镁矿与工业铝灰为原料制备镁铝尖晶石材料。分析讨论了不同煅烧温度对工业铝灰材料组成与微观结构的影响,并进一步研究了煅烧温度对制备镁铝尖晶石材料的组成、镁铝尖晶石相晶胞常数及材料微观结构的影响。用X射线衍射(XRD)和扫描电镜(SEM)对煅烧后试样的物相和显微结构进行研究。利用X′pert plus软件对试样中主晶相的晶格常数进行计算,比较不同温度煅烧试样的相对结晶度。结果表明:随着工业铝灰煅烧温度的升高,材料中主晶相六方晶型的刚玉相晶胞常数呈现各向异性的变化趋势。低品位菱镁矿与工业铝灰经1 400℃高温煅烧可以制备出以镁铝尖晶石为主晶相的镁铝尖晶石材料,该温度煅烧的镁铝尖晶石材料晶粒相对均匀、结构相对致密,主晶相镁铝尖晶石相晶格常数最大。

Magnesium aluminate spinel material was prepared by solid reaction with low-grade magnesite and industrial alu- mina ash as raw materials.The effect of sintering temperature on composition and microstructnre of industrial alumina ash was discussed firstly.For further study,the effects of sintering temperature on composition,crystal cell parameters,and mi- crostructure of magnesium aluminate spinel material were studied.Crystalline phases and microstructure of the sintered sam- ple were determined by XRD and SEM respectively.The lattice parameters of main crystalline phase and crystallinity of the samples sintered at different temperatures were calculated and compared by X＇Pert plus software.Results showed that lattice parameters of hexagonal corundum that is main crystalline phase in the industrial alumina ash presented a nonisotropic varia- tion tendency with the increase of sintering temperature.Magnesium aluminate spinel material could be prepared by solid re- action of low-grade magnesite and industrial alumina ash at 1 400 ℃.The cell parameter of main crystalline phase of the mag- nesium aluminate spinel material prepared at this temperature reached maximum, and relatively well-distributed grains in the material and relatively compact microstructure were both observed.