WERKWIJZE VOOR HET DOOR MALEN BEREIDEN VAN FIJN VERDEELDE POEDERVORMIGE STOFFEN.

摘要

1213494 Preventing agglomeration of powders DEUTSCHE GOLDUND SILBER SCHEIDEANSTALT 22 March 1968 [23 March 1967] 13931/68 Headings C5G and G10B [Also in Divisions A2 and F4] The agglomeration and reagglomeration of powdered materials is prevented by adding finely divided precipitated or pyrogenic hydrophobic silica to the materials either before or during their conversion to finely divided form. There may also be present finely divided, precipitated or pyrogenic hydrophilic silica. The hydrophobic silica may be pyrogenic SiO 2 with CH 3 - bonded to it, precipitated SiO 2 treated with organo silicon compounds, e.g. organohalogeno silanes or SiO 2 prepared by coprecipitation with water soluble organic compounds having reactive groups. There may be 0.1-20% of silica (overall) present and the ratio of hydrophobic to hydrophilic SiO 2 may be 1:10 to 1:1. The powdered material may be sulphur, MgO or chromium phosphate.