• 责任者：Zhang Huiqin (Key Laboratory of Orogenic Belts and Crustal Evolution ; School of Earth and Space Sciences ; Peking University ; Beijing 100871 ; China) ; Fan Chenzi
• 刊名：Acta Petrologica et Mineralogica
• 出版年：2013
• 卷期：33(6)
• 页码：p.966-974
• issnNo：ISSN1000-6524
• isbnNo：CN11-1966/P

K-birnessite was synthesized by air oxidation of Mn（Ⅱ） under alkaline conditions for ion exchange experiment.Energy-dispersive spectroscopy showed that K-birnessite has better cation exchange capacities with Ba2＋,Pb2＋,NH4＋ and Ag＋ than Li＋,Cu2＋,Zn2＋,Ni2＋,Mg2＋,Ca2＋,Na＋ and Cd2＋.X-ray powder diffraction and infrared spectra revealed that Li＋,Cu2＋,Ba2＋,Zn2＋,Ni2＋,NH4＋,Pb2＋,Mg2＋,Ca2＋,Na＋ and Cd2 ＋ exchanged birnessites preserved the interlayer structure with d spacing of about 0.7 nm except for Agbirnessite,but this exchange process greatly changed the crystallinity or the ordering of cations in the interlayer and MnO6 octahedra in the layers of birnessite.The thermal property of cation-exchanged birnessites examined by DSC-TGA curves indicated that the important phase transformation and structure evolution occurred in the ranges of 150～250℃ and 500～700℃.Cation-exchanged birnessites experienced a disorder state and recrystallization for new structural arrangement as the temperature increased.The nature of heated products depends on the nature of cations,especially the size of ion radius.Large cations of K＋,Ba2＋,Na＋,Pb2＋ and Ag＋ with radius larger than or close to 0.1 nm gave rise to hollandite type （2 × 2） tunnel and even todorokite type （3 × 3）tunnel manganese oxides.Bimessites doped with small cations （＜ 0.1 nm） of Mg2＋,Ca2＋,Cd2＋ and Zn2＋ cations decomposed into hausmannite and of Cu2＋,Ni2＋,Li＋ and heat-labile NH4＋ cations decomposed into bixbyite.