ABSTRACT
The development of the science required for ammonia synthesis started in the 19th century, and its subsequent rapid progress owes much to Haber, who first determined the equilibrium constant for the synthesis reaction in 1904. The successful development of the ammonia synthesis process resulted from the application of the then developed thermodynamic, kinetic and chemical engineering principles. The commercial ammonia synthesis catalyst is an excellent example of a heterogeneous catalyst, with one major component generating the activity, but requiring the addition of other compounds as promoters and stabilizers to increase its effectiveness and stability over long periods. All commercial ammonia synthesis catalysts are based on metallic iron promoted with alkali, and various metal oxides, such as those of aluminium, calcium or magnesium. Almost all ammonia synthesis catalysts are manufactured by fusing magnetite together with the required amounts of promoters to generate a homogeneous melt.
