The invention concerns a method for preparing low water uptake
precipitated silicas, comprising successive steps which consist in: (a)
producing an initial starter including a silicate, the silicate
concentration in said starter, expressed in SiO.sub.2 equivalent, being
less than 15 g/L; (b) bringing the medium pH to a value ranging between 7
and 8 by adding an acidifying agent, (c) in the resulting medium,
simultaneously adding a silicate and an acidifying agent the respective
amounts of silicate and acidifying agent added in time being specifically
such that, during the entire addition (1) the reaction medium pH stays
between 7 and 8, and (ii) the silicon concentration in the medium,
expressed in SiO.sub.2 equivalent, stays below 35 g/L; (d) adding an
acidifying agent in the medium resulting from step (c), so as to bring
the medium to a pH ranging between 3 and 6.5; and (e) filtering the
resulting aqueous silica dispersion, then drying the filter cake obtained
at the end of the filtering step. The invention also concerns low water
uptake silicas obtained by said method and their use, in particular for
reinforcing silicones or polymer or elastomer matrices.