1999. ------. [LARSON, A. T.] Ammonia Synthesis. United States Patent 1,667,322, Apr. 24, 1928. Chem. Abs., vol. 22, 1928, p. 2035.

Catalyst is prepared by forming particles from an intimate mixture of Fe oxide, K₂O, and MgO and treating the particles with a H₂-containing gas at 300°-700°.