1265.    ---------------.  [GRINEVICH, V. M.] Selection of New Raw Materials for Ammonia Catalyst.  Jour. Appl. Chem. (U.S.S.R.), vol. 18, 1945, pp. 313-321 (English summary); Chem. Abs., vol. 40, 1946, p. 3576.

        Study of Vysokogorsk, Magnitogorsk, and Pokrovsk ores, after magnetic separation from SiO₂, showed the possibility of preparation of an NH₃ catalyst, since the presence of SiO₂ up to 2% does not show a negative effect on the catalyst activity, provided that enough K₂O is present.  This effect is explained by separation of much SiO₂, with K₂O in the process of catalyst formation, with consequent formation of essentially pure magnetite crystals.  The ore is subjected to double magnetic separation and alkaline fusion and followed by a double separation to yield 23% of finished product.  The catalyst can be regenerated by oxidation of KNO₃.