402.    BUECHNER, -----.  HECHEL, H., AND ROELEN, O.  Behavior of Inorganic Impurities in Kieselguhr.  FIAT Reel K-20, frames 99-102, 1939; PB 70,211; TOM Reel 287, frames 99-102.

                  Seasonal variations in the quality of kieselguhr 12 o. were observed.  Investigation led to the opinion that these variations are due to storage in the open.  When kieselguhr lies in heaps, the Fe oxidizes and the S is transformed into H₂SO₄.  These processes are termed “cold combustion” and are said not to occur when kieselguhr is stored flat.  When heated to 400°-500°, Fe and S form ferrous sulfate.  When the kieselguhr is heated to 1,000° the ferrous sulfate is transformed into ferric silicate.  The proportion of Fe, which with the O₂ of the air has already been transformed to the ferrous form, remains unchanged.  Ca, S, and Al cause no changes by storage.

                  BUELOW, H.  See abs. 3137.

                  BUFFLEB, H.  See abs. 2679, 2680, 2681, 2682.

                  BUFORD, C. B.  See abs. 1268.