NOVEL METHOD OF PREPARING PRECIPITATED SILICAS, NOVEL PRECIPITATED SILICAS, AND THEIR USES, IN PARTICULAR FOR REINFORCING POLYMERS

摘要

The invention relates to a novel process for preparing a precipitated silica, in which:
a silicate is reacted with an acidifying agent, so as to obtain a suspension of precipitated silica,said suspension of precipitated silica is filtered, so as to obtain a filter cake,said filter cake is subjected to a liquefaction operation comprising the addition of an aluminum compound,after the liquefaction operation, a drying step is performed, characterized in that at least one polycarboxylic acid is added to the filter cake, during or after the liquefaction operation.;The invention also relates to novel precipitated silicas and to uses thereof.

主权项

1. A process for preparing a precipitated silica, the process comprising:
precipitating a silicate and an acidifying agent by:
(i) forming an aqueous feedstock with a pH of between 2 and 5,(ii) simultaneously adding silicate and acidifying agent to said feedstock, such that the pH of the reaction medium is maintained between 2 and 5,(iii) discontinuing the addition of the acidifying agent while continuing the addition of the silicate to the reaction medium until a pH value of the reaction medium of between 7 and 10 is obtained,(iv) simultaneously adding silicate and acidifying agent to the reaction medium, such that the pH of the reaction medium is maintained between 7 and 10,(v) discontinuing the addition of the silicate while continuing the addition of the acidifying agent to the reaction medium until a pH value of the reaction medium of less than 6 is obtained, thus providing a silica suspension, filtering the silica suspension to form a filter cake, subjecting the filter cake to a liquefaction operation comprising the addition of at least one aluminum compound,wherein at least one polycarboxylic acid is added to the filter cake, either during the liquefaction operation, or after the liquefaction operation and before a drying step.