采用流动反应器研究了丙烯热解和在铁黄颗粒表面生成热解炭的化学热力学以及化学气相沉积(CVD)过程.发现在600 ℃之前丙烯热解发生的化学气相沉积基本为表面反应过程;在热解炭沉积过程中铁黄颗粒的比表面积迅速减少,同时由于脱去水分而发生失重;随着温度的升高,Fe2O3逐渐被还原为Fe3O4和FeO,在800 ℃以上Fe2O3完全被还原为Fe3C.在化学气相沉积过程中,500 ℃以前铁黄可以保持大长径比形貌,在600 ℃～700 ℃之间则生成长径比较小的哑铃型颗粒.非球形氧化铁颗粒在氢气还原过程中能够保持原有形状,同时被还原成为单质铁.上述化学气相沉积和气化过程可以用于制备热解炭包覆的或者纯净的非球形铁颗粒材料.
参考文献
| [1] | Cornell R M;Schwertman U.The iron oxides structures,properties,reactions,occurrence and use[M].Weinheim:Wiley-VCH,1996 |
| [2] | Butler P;Wagner C;Guidotti R et al.Long-life multi-tap thermal battery development[J].Journal of Power Sources,2004,136:240-245. |
| [3] | Wolska E;Schwertman U .Nonstoichiometric structures during dehydroxylation of Goethite[J].Zeitschrift fur Kristallographie,1989,189:223-237. |
| [4] | Chambaere D G;Degrave E .The α-FeOOH to α-Fe2O3 phase transformation:Structural and magnetic phenomena[J].Physics and Chemistry of Minerals,1985,12:176-184. |
| [5] | Sugimota T;Kazuo S;Atsushi M .Formation mechanism of nano-disperse pseudocubic α-Fe2 O3 particles from condensed ferric hydroxide gel[J].J Colloid Surface Sci,1993,159:372-382. |
| [6] | Philipse A P;Van Bmggem M P B;Pathmanavbaron C .Magnetite silica dispersion:Preparation and stability of surface modified silica particles with a magnetic core[J].LANGMUIR,1994,10:92-99. |
| [7] | Jing Z H;Wu S H .Synthesis and characterization of nano-disperse Hematite nanoparticles modified by surfactants via hydrothermal approach[J].Materials Letters,2004,58(27-28):3637-3640. |
| [8] | White W B;Johnson S M;Dantzig G B .Chemical Equilibrium in complex mixtures[J].Journal of Chemical Physics,1958,28:751-755. |
| [9] | D. Walter;G. Buxbaum;W. Laqua .The mechanism of the thermal transformation from goethite to hematite[J].Journal of thermal analysis and calorimetry,2001(3):733-748. |
| [10] | Goss C J .The kinetics and reaction mechanism of the Goethite to Hematite transformation[J].Mineralogical Magazine,1987,51:437-451. |
| [11] | Ferrelto L;Glisenti A .Study of the surface acidity of an hematite power[J].Journal of Molecular Catalysis A:Chemical,2002,187(01):119-128. |
| [12] | Fan HL;Song BZ;Liu JH;Yang ZQ;Li QX .Thermal formation mechanism and size control of spherical hematite nanoparticles[J].Materials Chemistry and Physics,2005(2/3):321-325. |
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