Thermogravimetric study of magnetite reduction at low temperature |
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Authors: | G Liberti G Servi A Guaglio C Ruffino N Pernicone |
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Institution: | (1) G. Donegani Research Institute Montecatini Edison S. p. A. Novara, Italy |
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Abstract: | Results on hydrogen reduction of pure magnetite to iron at low temperature are reported as part of research on ammonia synthesis catalyst. Experimental work was carried out by thermogravimetry and by electron microscopy.The reduction has a typical S-shaped kinetic curve, with a poorly reproducible induction period. The slope of the reduction curve at 50% conversion (k
0.5) was found to depend on sample mass (2–50 mg), particle size, temperature (220–280 C) and presence of moisture in the hydrogen
.The results suggest both interparticle and intraparticle (through iron ash) diffusion to be slow. Morphological examinations of the sample at various reduction degrees support this interpretation.
Zusammenfassung Die Ergebnisse der Reduktion von reinem Magnetit zu Eisen durch Wasserstoff bei niedrigen Temperaturen werden als Teil einer Forschungsarbeit über Katalysatoren zur Ammoniak-Synthese mitgeteilt. Die Versuche wurden mittels Thermogravimetrie und Elektronenmikroskopie durchgeführt.Die Reduktion verläuft nach einer typisch S-förmigen kinetischen Kurve, mit einer schlecht reproduzierbaren Induktionsperiode. Es wurde festgestellt, daß die Steile der Kurve bei 50% Konversion (k
0.5) von der Probenmenge (2–50 mg), der Teilchengröße, der Temperatur (220 bis 280 ) und der Feuchtigkeit des Wasserstoffes
abhängt.Diese Ergebnisse lassen darauf schliessen, daß sowohl die interpartikuläre als auch die intrapartikuläre Diffusion (durch die Eisen-Asche) langsam ist. Diese Deutung wird durch morphologische Prüfung des Musters bei verschiedenen Reduktionsstufen unterstützt.
Résumé On communique les résultats obtenus en réduisant par l'hydrogène à basse température la magnétite pure en fer, travail faisant partie de recherches sur les catalyseurs pour la synthèse de l'ammoniac. Les expériences ont été effectuées par thermogravimétrie et par microscopic électronique.La courbe cinétique de la réduction présente la forme en S type, avec une période d'induction peu reproductible. Il est apparu que la pente de la courbe de réduction, pour un taux de conversion de 50% (k
0.5) dépendait de la prise d'essai (2–50 mg), de la dimension des particules, de la température (220 à 280 ) et de la présence d'humidité dans l'hydrogène
.Ces résultats permettent de conclure que les processus de diffusion sont lents, qu'ils soient de type interparticule ou intraparticule. L'examen morphologique des échantillons pour divers degrés de réduction a confirmé cette interprétation.
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![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) . ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) , ![CHcy](/content/h825m813x0711844/xxlarge1063.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![khcy](/content/h825m813x0711844/xxlarge1093.gif) ![kcy](/content/h825m813x0711844/xxlarge1082.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![SHCHcy](/content/h825m813x0711844/xxlarge1065.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) 50% ( 0.5) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![Bcy](/content/h825m813x0711844/xxlarge1041.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![tscy](/content/h825m813x0711844/xxlarge1094.gif) (2–50 ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ), ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) , ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) (220 –280 ) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) (![Rcy](/content/h825m813x0711844/xxlarge1056.gif) 2 )=1,2 ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ). ![ldquo](/content/h825m813x0711844/xxlarge8220.gif) ![IOcy](/content/h825m813x0711844/xxlarge1025.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![softcy](/content/h825m813x0711844/xxlarge1100.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![gcy](/content/h825m813x0711844/xxlarge1075.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![softcy](/content/h825m813x0711844/xxlarge1100.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) , ![CHcy](/content/h825m813x0711844/xxlarge1063.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Fcy](/content/h825m813x0711844/xxlarge1060.gif) ![Fcy](/content/h825m813x0711844/xxlarge1060.gif) ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) , ![kcy](/content/h825m813x0711844/xxlarge1082.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) , ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ucy](/content/h825m813x0711844/xxlarge1059.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) , ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![khcy](/content/h825m813x0711844/xxlarge1093.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) . ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![kcy](/content/h825m813x0711844/xxlarge1082.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![tscy](/content/h825m813x0711844/xxlarge1094.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![Dcy](/content/h825m813x0711844/xxlarge1044.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![gcy](/content/h825m813x0711844/xxlarge1075.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![CHcy](/content/h825m813x0711844/xxlarge1063.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![kcy](/content/h825m813x0711844/xxlarge1082.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![softcy](/content/h825m813x0711844/xxlarge1100.gif) ![Mcy](/content/h825m813x0711844/xxlarge1052.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Bcy](/content/h825m813x0711844/xxlarge1041.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![tscy](/content/h825m813x0711844/xxlarge1094.gif) ![Rcy](/content/h825m813x0711844/xxlarge1056.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![zhcy](/content/h825m813x0711844/xxlarge1078.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![Icy](/content/h825m813x0711844/xxlarge1048.gif) ![CHcy](/content/h825m813x0711844/xxlarge1063.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![pcy](/content/h825m813x0711844/xxlarge1087.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![scy](/content/h825m813x0711844/xxlarge1089.gif) ![tcy](/content/h825m813x0711844/xxlarge1090.gif) ![Acy](/content/h825m813x0711844/xxlarge1040.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) ![Ocy](/content/h825m813x0711844/xxlarge1054.gif) ![Vcy](/content/h825m813x0711844/xxlarge1042.gif) ![lcy](/content/h825m813x0711844/xxlarge1083.gif) ![IEcy](/content/h825m813x0711844/xxlarge1045.gif) ![Ncy](/content/h825m813x0711844/xxlarge1053.gif) .
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本文献已被 SpringerLink 等数据库收录! |
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