Studies were conducted on the production of highly dispersed silicas using the technique of precipitation from solutions of sodium metasilicate and ammonium chloride. Parameters of the precipitation process were optimised in order to obtain highly dispersed as well as uniform and stable silicas. The silicas obtained were subjected to elementary physicochemical analysis, the tendency of the silica particles to form aggregates and agglomerates was examined using scanning electron microscopy (SEM) and dynamic fight scattering (DLS), and surface analysis was performed using the BET technique. The silicas obtained manifested exceptionally low bulk density and a high capacity to absorb paraffin oil. (C) 2003 Society of Chemical Industry.