scholarly journals The activity of fused-iron catalyst doped with lithium oxide for ammonia synthesis

2016 ◽  
Vol 18 (2) ◽  
pp. 78-83 ◽  
Author(s):  
Roman Jedrzejewski ◽  
Zofia Lendzion-Bieluń ◽  
Walerian Arabczyk
Keyword(s):  
Solid Solution ◽  
Active Sites ◽  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Lithium Oxide ◽  
Potassium Oxide ◽  
Catalyst Precursor ◽  
Two Phases ◽  
Full Reduction ◽  
Fused Iron Catalyst

Abstract The iron catalyst precursor promoted with Al2O3, CaO, and Li2O was obtained applying the fusing method. Lithium oxide forms two phases in this iron catalyst: a chemical compound with iron oxide (Li2Fe3O4) and a solid solution with magnetite. The catalyst promoted with lithium oxide was not fully reduced at 773 K, while the catalyst containing potassium was easily reducible at the same conditions. After reduction at 873 K the activity of the catalyst promoted with lithium oxide was 41% higher per surface than the activity of the catalyst promoted with potassium oxide. The concentration of free active sites on the surface of the catalyst containing lithium oxide after full reduction was greater than the concentration of free active sites on the surface of the catalyst promoted with potassium oxide.

scholarly journals Reduction Process of Iron Catalyst Precursors for Ammonia Synthesis Doped with Lithium Oxide

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 494 ◽  
Author(s):  
Roman Jedrzejewski ◽  
Zofia Lendzion-Bielun
Keyword(s):  
Solid Solution ◽  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Reduction Process ◽  
Xrd Analysis ◽  
Lithium Oxide ◽  
Molar Ratio ◽  
Transient Phase ◽  
Phase Reduction ◽  
Magnetite Phase

Iron catalyst precursors promoted with oxides of calcium, aluminum, and lithium were prepared by a fusion method. Using XRD analysis, it was found that catalyst precursors had a magnetite structure. Lithium oxide, which is dependent on the Fe2+/Fe3+ molar ratio in a catalyst, was built into the magnetite structure as a solid solution and/or formed a separate Li2Fe3O4 phase. Lithium oxide forming the solid solution in magnetite accelerated the magnetite phase reduction. However, it was observed that magnetite, in the presence of lithium oxide, was not reduced to iron directly, but to a transient phase, Li2O·xFeO, where x < 3 was formed, which meant that the reduction to iron was much slower. Activity of the catalysts promoted with lithium oxide increased, while the degree of reduction increased.

Iron catalyst for ammonia synthesis doped with lithium oxide

2009 ◽  
Vol 10 (14) ◽  
pp. 1821-1823 ◽  
Author(s):  
Walerian Arabczyk ◽  
Izabella Jasinska ◽  
Roman Jedrzejewski
Keyword(s):  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Lithium Oxide

Heterogeneity of ingot of the fused iron catalyst for ammonia synthesis

2011 ◽  
Vol 400 (1-2) ◽  
pp. 48-53 ◽  
Author(s):  
Zofia Lendzion-Bieluń ◽  
Roman Jędrzejewski ◽  
Ewa Ekiert ◽  
Walerian Arabczyk
Keyword(s):  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Fused Iron Catalyst

A novel fused iron catalyst for ammonia synthesis promoted with rare earth gangue

2008 ◽  
Vol 26 (5) ◽  
pp. 711-716 ◽  
Author(s):  
Xiujin YU ◽  
Bingyu LIN ◽  
Jianxin LIN ◽  
Rong WANG ◽  
Kemei WEI
Keyword(s):  
Rare Earth ◽  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Fused Iron Catalyst

scholarly journals The effect of iron nanocrystallites’ size in catalysts for ammonia synthesis on nitriding reaction and catalytic ammonia decomposition

2011 ◽  
Vol 9 (2) ◽  
pp. 240-244 ◽  
Author(s):  
Rafał Pelka ◽  
Karolina Kiełbasa ◽  
Walerian Arabczyk
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Atmospheric Pressure ◽  
Active Sites ◽  
Ammonia Synthesis ◽  
Iron Catalyst ◽  
Ammonia Decomposition ◽  
Mean Size ◽  
Catalytic Ammonia Decomposition

AbstractIron catalyst for ammonia synthesis of various mean sizes of iron nanocrystallites were nitrided with ammonia in a differential reactor equipped with systems that made it possible to conduct both thermogravimetric measurements and hydrogen concentration analyses in the reacting gas mixture. The nitriding process was investigated under atmospheric pressure at the temperature of 475°C. It was found that along with an increase of mean size of iron nanocrystallites, with a decrease of specific surface area of the samples, nitriding degree of solid samples increased. At the same time the rate of surface reaction of catalytic ammonia decomposition decreased. Along with an increase of the samples’ specific surface area an increase of the catalyst’s activity was observed. However, it was also observed that the concentration of active sites on the catalysts’ surface decreased along with an increase of specific surface area.

scholarly journals Determination of the Content of Promoters in Magnetite and Wustite Phases in the Fused Iron Catalyst

2013 ◽  
Vol 15 (1) ◽  
pp. 27-29 ◽  
Author(s):  
Zofia Lendzion-Bieluń ◽  
Roman Jędrzejewski
Keyword(s):  
Aluminum Oxide ◽  
Iron Catalyst ◽  
Potassium Oxide ◽  
Oxide Content ◽  
Icp Oes ◽  
The Third ◽  
Instrumental Methods ◽  
Fused Iron Catalyst ◽  
Magnetite Phase

Taking advantage of differences in etching rates of crystallographic phases, forming an oxidized form of the fused iron catalyst, a content of promoters in main phases, magnetite and wustite, was determined. A calcium oxide content in magnetite and wustite was 0.54 wt% and 3.59 wt%, respectively. Aluminum oxide was found in the magnetite phase, and its content was 4.5 wt%. The third promoter, potassium oxide, was almost completely located outside these phases. XRD and ICP-OES instrumental methods were used in the investigations.

Sign in / Sign up

Export Citation Format

Share Document