摘要
本文采用ＤＴＡ、ＴＧ、ＨＴＸＴＤ和ＴＥＭ研究了ＳｉＯ２包敷α－ＦｅＯＯＨ粒子的脱水过程。从ＤＴＡ和ＴＧ曲线算得的动力学参数表明，ＳｉＯ２包敷α－ＦｅＯＯＨ粒子的脱水过程近似为一级反应，其活化能大于未处理的α－ＦｅＯＯＨ粒子的活化能。ＨＴＸＲＤ和ＴＥＭ的测量结果表明，α－ＦｅＯＯＨ热分解成α－Ｆｅ２Ｏ３同时形成晶核和条形微孔，这可能是Ｘ射线衍射峰展宽的主要原因。随着温度增加，微孔织构转变为中孔或大孔织构，大约在８００℃以上逐渐消失。对于ＳｉＯ２包敷α－ＦｅＯＯＨ，其相应的热变化温度移向高温。
Abstract The dehydration process of SiO2 coated α-FeOOH has been investigated by DTA, TG, HTXRD and TEa measurementS. The kinetic parameters caculated from DTA and TG curves indicate that the dehydstien proess of SiO2 coatde α-FeOOH is about first order reaction, and its apparent activation energy is higher than that of the untreated α-FeOOH. The results from HTXRD and TEM measurements show that the thermal decomposition of α-FeOOH into α-Fe2O3 leads to the simultaneous formation of the crystal nuclei and of the slit--shaped micropores, which may be the main reason to broad X-ray diffraction lines. With the temperature increasing, the microporous texture is changed into a mesoporous or macroporous texture, and it almost disappears at the temperature above 800℃ or so. In the case of silica coated αFeOOH, its thermal variation temperature shifts to the high temperature
基金
国家教委重大资助
