PATENTS

2835.  ROTTIG, W., GROSS, H. W.,  ROYEN, P.,AND SCHENK, K.   (Ruhrchemie A. G. and Lurgi Gesellschaft für Waermetechnik).  Preparation of an Iron Silica-Gel Fischer-Tropsch Catalyst.  United States Patent  2,617,774, Nov. 11, 1952; appl. filed Sept. 9, 1950, Serial No.  184,114;  3 claims (Cl. 252-451). 

            Process consists of precipitating a hot solution of Fe nitrate, while intensively stirring, with a hot caustic soda solution in such a manner that the pH value after precipitation is 6.8-7.2.  The precipitated mass is  washed to a K₂O calculated content of no more than 0.5 part by weight of K₂O for every 100  parts by weight of Fe content, stirring at first with a small amount of H₂O. then converting into a suspension by addition of further amounts of H₂O.  Enough K-water-glass solution is added to this suspension to give 20-25 parts by weight of SiO₂ for every 100 parts by weight of Fe contained in the catalyst.  Then enough nitric acid is added to give for the catalyst mass remaining after filtration a K₂O; SiO₂ ratio of 1: 4-1: 5.  The catalyst is dried, molded, and reduced at 260°-300° C. to a point at which the catalyst contains 30-50% of its total Fe content in the form of free Fe.  High gas velocity of 1-2 m. per sec. is used during reduction.  3 United States patents cited.