Process for preparing iron-based catalysts for the synthesis of ammonia and catalysts so obtained
AssigneeFertimont S.p.A.
InventorsNicola Pernicone, Francesco Ferrero, Antonio Gennaro
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Abstract
A process for preparing iron-based catalysts for the synthesis of ammonia by melting of magnetite along with metal oxides as promoters, subsequent cooling of the molten mass and reduction thereof to the desired size, wherein the abovesaid cooling occurs at a rate higher than 25.degree. C./min., preferably ranging from 100.degree. C. to 1600.degree. C./min., at a temperature ranging from 1700.degree. C. to 700.degree. C. The present invention relates to a process for preparing iron-based catalysts having a high activity in the ammonia synthesis, and to the catalyst so obtained.
Claims10
A process for preparing an ammonia synthesis catalyst based on iron by melting magnetite or a mixture of iron oxides having the composition of magnetite, together with 1 to 10% by weight of a mixture of Al.sub.2 O.sub.3, K.sub.2 O, CaO, MgO, and SiO.sub.2 as promoter, subsequently cooling the melt, and reducing same to the desired size, characterized in that the cooling of the melt is accomplished by quenching at a rate higher than 25.degree. C./minute.
An ammonia synthesis catalyst based on iron consisting essentially of magnetite together with 1 to 10% by weight of a mixture of metal oxides as defined below as promoter, and prepared by melting magnetite or a mixture of iron oxides having the composition of magnetite, together with 1 to 10% by weight of a mixture of Al.sub.2 O.sub.3, K.sub.2 O, CaO, MgO, and SiO.sub.2 as promoter, subsequently cooling the melt, and reducing same to the desired size, characterized in that the cooling of the melt is accomplished by quenching at a rate higher than 25.degree. C./minute, and in that the catalyst has a reticular structure of magnetite crystallites, surrounded by promoter oxide, whose sizes range from 10 to 100 .mu.m, and further characterized in having an X-ray diffraction pattern including at least one of the two following series of lines A and B:
- ______________________________________ d(.ANG.) Intensity ______________________________________ A 8.48 VW 5.63 VW 4.57 VVW 2.94 VW 2.676 VW 2.542 VW 2.347 VVW 2.080 VW B 5.13 VVW 2.609 W 2.477 VW 2.368 VVW 2.228 VVW 1.656 VVW 1.644 VW 1.627 VVW 1.576 VW 1.556 VVW 1.467 W ______________________________________
- where "V" means very and "W" means weak.
Dependencies are inferred from the claim text.