Magnetite Catalyst Containing Cobalt

The ICI cobalt catalyst, which is reported to contain 10-20% cobalt oxide, was developed for use at 80 bar synthesis pressure and maximum temperatures as low as 460°C. These conditions were significantly different from the usual single-stream ammonia plants which operated at 150 bar or higher and temperatures up to 500°C. 

From experimental work with precipitated cobalt-iron catalysts it appeared that the cobalt reacted with alumina giving cobalt spinels, which helped to form smaller iron and cobalt crystallites during reduction and to increase the surface area to make the catalyst more stable and less sensitive to oxide forming poisons. In the presence of potash, cobalt was able to decrease the reduction temperature. 

Development work was successful and, following a typical fusion production procedure, the new catalyst could be reduced and operated at lower temperature under normal conditions in conventional plants. Reduction began at 380°C in the new AMV and LCA processes introduced by ICI in 1985 and 1988 respectively. The AMV plants have operated at more than 100% capacity of a pressure of only 60 bar. The life of the new catalyst has been very satisfactory, and could be operated of pressures much closer to those of the reformers, albeit with large converters. 

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Fes04 based catalysts containing cobalt is one of the main progresses for magnetite based fused iron catalysts. 

The group of metals forming low-stability or unstable nitrides includes Mn, Fe, Co, Ni, Tc and Re. As in the case of iron a clear structural sensitivity was found for rhenium but the role of promoters remains the subject of discussion. There are also indications of structure sensitivity for cobalt and nickel. It was attempted to improve the activity of the classical magnetite catalyst by alloying with nickel or cobalt. The only commercial catalyst is a cobalt containing magnetite [392],... 

Without noble metals in the composition of the catalyst. The production cost of wiistite catalyst is much lower than that of cobalt-containing magnetite-based catalyst and Ru/AC catalysts. 

Ammonia synthesis catalysts consisting of magnetite containing a small amount of cobalt oxide. (Societe Chimique de la Grande Paroisse). NL 7203559 (1972) US 3839229 (1974). 

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