3363.     TEICHNER, S., AND PERNOUX, E.  [Ultrasonic Fractionation of a Kieselguhr Carrier of a Fischer Catalyst.]  Compt. rend., vol. 230, 1950, pp. 1063-1064.

        Suspension of an acid-treated kieselguhr (Filter Cel) in distilled H2O was subjected to an ultrasonic treatment (v=970,000).  2 fractions were obtained:  One (12% of the initial weight of the kieselguhr) was a stable dispersion; the other remained precipitated on the bottom of the vessel.  The specific surface, determined by absorption of N2 at 195, of the dispersed fraction was 40 m.2 per gm., that of the initial acid-treated kieselguhr 27 m.2 per gm.  Besides, treatment with a 5% H2O solution of Na2CO3 involved losses in weight of 21.6 and 14.5%, respectively.  Examination under the electronic microscope revealed an extensive flocculent appearance for the dispersed fraction and considerably less so for the same fraction treated with carbonate.  The precipitated fraction had a specific surface of 15.2 m.2 per gm. and a loss in weight by the carbonate treatment of 9%.  The properties were similar to those of a kieselguhr untreated with acid.  The ultrasonic treatment, thus, furnishes further proof of the formation by the acid treatment of kieselguhr of a silica gel of flocculent appearance with a broad specific surface, and easy reaction with Na2CO3.  Such a gel is formed for the most part in the dispersed phase of ultrasonic treatment.