熔盐辅助煅烧法制备纳米MgO

Synthesis of MgO nano-crystallite powders by a molten salt method

以无水硫酸镁、氨水和月桂酸钠作为原材料,采用醇水体系一步法制备了表面修饰纳米Mg（OH）2,经熔盐LiNO3辅助煅烧制备纳米MgO。用XRD和FT-IR表征前驱物Mg（OH）2的结构及形貌,通过TG-DTA确定煅烧温度,用XRD和TEM对纳米MgO的结构和形貌进行表征。讨论了氨水浓度、氨水用量、煅烧温度、煅烧时间和熔盐添加量对纳米MgO颗粒尺寸和硬团聚程度的影响。初步认为纳米MgO是通过成核、长大过程形成的。通过调控煅烧时间、煅烧温度、熔盐比例,可以将MgO平均粒径有效控制在20～100 nm范围。

Surface modified Mg（OH）2 particles have been synthesized by a one-step process using magnesium sulfate, ammonia liquor and sodium laureate as raw materials in alcohol-water systems. MgO nano-crystallite powders were subsequently synthesized by calcination of the Mg （OH）2 precursor using a molten salt method; this process was carried out at different temperatures, for different times, and with different molten salt contents. The structure and morphology of the Mg（OH）2 precursor were characterized by XRD and FT-IR. The effects of varying the calcination temperature and molten salt type were studied by TG-DTA analysis. The structure and appearance of the nanometer-scale MgO were studied by TEM and XRD. The effects of varying ammonia liquor content, ammonia liquor concentration, annealing temperature, annealing time and molten salt content on MgO nano-crystallite powder were investigated. The mechanism of formation of MgO is discussed in terms of nucleation and growth processes. It was found that the average crystallite sizes of the resulting MgO powders could be effectively controlled in the range 20 - 100 nm by changing the calcination temperature, calcination time and molten salt content.