Preparation of α-Bi2O3 from bismuth powders through low-temperature oxidation

来源期刊:中国有色金属学报(英文版)2012年第9期

论文作者:夏纪勇 唐谟堂 陈萃 金胜明 陈永明

文章页码:2289 - 2294

关键词:铋粉;低温氧化;α-Bi2O3;氧化动力学

Key words:bismuth powder; low-temperature oxidation; α-Bi2O3; oxidation kinetics

摘    要:纳米金属铋粉在低于873.15 K的温度下被氧化而制备成α-Bi2O3粉体,采用XRD、SEM、TEM和HRTEM 等技术表征α-Bi2O3 粉体的晶体结构和形貌,通过TGA技术研究铋粉的低温氧化动力学行为。结果表明,纳米铋粉在较低的温度下熔融成铋珠,铋珠结合长大并氧化生成不规则的Bi2O3 粉体,铋珠氧化机理符合核收缩模型;动力学控制步骤随着氧化时间的变化而变化,在0~10 min内,铋珠氧化动力学表现为化学反应控制,然后转化为O2内扩散控制,低温氧化表观反应活化能为55.19 kJ/mol。

Abstract: α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.

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