2943.     ---------------.  [RUHRCHEMIE, A.-G.]  [Kieselguhr.]  FIAT Reel K-20, 1938, frames 18-23; PB 70,211; TOM Reel 287.

        Microphotographs of 12 kieselguhr samples show great changes in structure after regeneration.  It is believed that an examination of the microtexture of fresh and spent catalysts will provide valuable explanations on the evaluation of catalysts for the gasoline synthesis.  The solubility of kieselguhr is determined by stirring at 80°-95° with various solutions occurring in the manufacture of catalysts, filtering and washing with hot water.  In the filtrate, SiO₂, Fe₂O₃, Al₂O₃, and CaO are determined.  Table and diagram.