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Utilization of spent iron catalyst for ammonia synthesis

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Arabczyk W., Narkiewicz U., Lendzion-Bieluń Z., Moszyński D., Pełech I., Ekiert E., Podsiadły M., Pelka R., Jędrzejewski R., Moszyńska I., Sibera D.

Polish Journal of Chemical Technology

2007

vol. 9

issue 3

108-113

Several methods of the utilization of spent iron catalyst for ammonia synthesis have been presented. The formation of iron nitrides of different stoichiometry by direct nitriding in ammonia in the range of temperatures between 350°C and 450°C has been shown. The preparation methods of carbon nanotubes and nanofibers where iron catalyst catalyse the decomposition of hydrocarbons have been described. The formation of magnetite embedded in a carbon material by direct oxidation of carburized iron catalyst has been also presented.

Kinetics of nanocrystalline iron nitriding

88%

Arabczyk W., Zamłynny J., Moszyński D.

Polish Journal of Chemical Technology

2010

vol. 12

issue 1

38-43

Nitriding of nanocrystalline iron was studied under the atmosphere of pure ammonia and in the mixtures of ammonia - hydrogen - nitrogen at temperatures between 350°C and 500°C using thermogravimetry and x-ray diffraction. Three stages of nitriding were observed and have been ascribed to the following schematic reactions: (1) α-Fe → γ'-Fe4N, (2) γ'- Fe4N → ε - Fe3N and (3) ε - Fe3N → ε - Fe2N. The products of these reactions appeared in the nitrided nanocrystalline iron not sequentially but co-existed at certain reaction ranges. The dependence of a reaction rate for each nitriding stage on partial pressure of ammonia is linear. Moreover, a minimal ammonia partial pressure is required to initiate the nitriding at each stage.

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2 Polish Journal of Chemical Technology

1 2010

1 2007

2 Arabczyk W.

2 Moszyński D.

1 Ekiert E.

1 Jędrzejewski R.

1 Lendzion-Bieluń Z.

1 Moszyńska I.

1 Narkiewicz U.

1 Pelka R.

1 Pełech I.

1 Podsiadły M.

1 Sibera D.

1 Zamłynny J.

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Utilization of spent iron catalyst for ammonia synthesis

Kinetics of nanocrystalline iron nitriding