New silicas their proparation process and their use as fillers especially for paper.

摘要

New silicas characterised in that they exhibit a surface chemistry such that their number of cationic sites, expressed in micromoles/m<2> of silica, is higher than 0.05. They are prepared by a process consisting in treating a suspension of silica which has a pH of not more than 8 with an organic or inorganic salt of an at least divalent metal, in then again raising the pH of the medium to a value higher than or equal to 3.5, in separating the treated silica from the said medium and in then drying the recovered silica. The invention also relates to the use of the said silicas as fillers for paper.