铁(Ⅱ)无机物热解制备γ-Fe_2O_3及其机理  

PREPARATION OF γ-Fe_2O_3 THROUGH PYROLYSIS OF IRON (Ⅱ) INORGANIC COMPOUNDS AND ITS MECHANISM

作　　者：吴东辉[1] 施新宇[1] 章忠秀[1] 施磊[1] 

机构地区：[1]南通大学化学化工学院,江苏南通226007

出　　处：《硅酸盐学报》2006年第6期699-702,共4页Journal of The Chinese Ceramic Society

基　　金：江苏省高校自然科学研究指导性计划(05KJD430163)资助项目

摘　　要：用硫酸亚铁为原料,以氢氧化钠、氨水或碳酸钠水溶液作沉淀剂,得到相应的氢氧化物或碳酸盐沉淀物作前驱体,在存在5O42-或CO32-时, 500℃下进行热解,即使原料中含有少量Fe(Ⅲ),热解产物仍为纯γ-Fe2O3。用X射线衍射、透射电镜对产物进行了表征。发现其转变机理为:Fe(Ⅱ) 的无机物先经空气中的氧气氧化成Fe3O4,而后进一步被氧化成γ-Fe2O3。在无SO42-或CO32-时,在相同的条件下进行热解,产物却为α-Fe2O3。Maghemite was directly prepared by pyrolysis of ferrous hydroxide or ferrous carbonate as precursors in the presence of SO4^2- or CO3^2- at 500℃ using iron（Ⅱ） sulfate precipitated by NaOH, NH3＋H2O or Na2CO3 solution as starting materials, even with small amounts of Fe（Ⅲ）. The products were characterized by X-ray diffraction and transmission electron microscope. It is found that the conversion mechanism is the oxidation of ferrous inorganic compounds to Fe3O4 by oxygen, and then further oxidation to maghemite. In contrast, hematite was obtained as the product of pyrolysis in the absence of SO4^2- or CO3^2- under the same conditions.

关 键 词：γ-三氧化二铁 热解 转变机理 铁磁材料 

分 类 号：TQ586.1[化学工程—精细化工] TK6[动力工程及工程热物理—生物能]