Low Temperature Synthesis of Magnesium Aluminate Spinel from AlOOH and MgO powder

摘要

Ultrafine MgAl_2O_4 powders have been successfully synthesized by solid-state reaction from the mixture of AlOOH and MgO at the lower temperature. The samples were investigated by DTA/TG, XRD and SEM analyses. The results showed that AlOOH can be decomposed into γ-Al_2O_3 from DG/TDA curves, which can improve the activity of Al_2O_3 and promote the process of solid-state reaction. The XRD analysis showed the single-phase MgAl_2O_4 was formed at 1400°C. Meanwhile it was detected by ICP-MS that the purity of powders was 99.995%. The SEM images showed that the mineralizer containing fluoride such as AlF_3, NH4F can promote the resultant to grow into regular octahedrons and disperse the particles. The XRD analysis indicated the mixture containing 5% AlF_3 can transform the integrated MgAl_2O_4 powders at 1200°C, nearly 200°C lower than general solid-state reaction. Furthermore, The SEM images showed that fluoride can crystal the fine particles into the larger MgAl_2O_4 crystals, about 0.5～1.5μm.