US Patent 8454919 Production of precipitated silica

Precipitated silica is produced by a process that includes a step for filtering and washing an aqueous suspension (S), comprising the following steps:(a) filtering a first portion (S1) of a precipitated silica suspension (S), whereby a cake (G1) is formed and said cake (G1) is then washed and a suspension (S′1) is formed by suspending the thereby obtained washed cake (G1), notably by dilution with water;(b) filtering a second portion (S2) of the suspension (S), whereby a cake (G2) is obtained; and(c) filtering said suspension (S′1) emanating from step (a) through the cake (G2) obtained at the end of step (b), employed as a filtration precoating layer.