| abstract |
The present invention provides a composition comprising an acidified aqueous solution of (1) micro colloidal silicic acid, (2) boric acid, and (3) a water absorbing additive, having a pH value of equal to or less than 1, wherein the micro colloidal silicic acid has particle sizes in the range of 1-8 nm, especially in the range of 1.5-6 nm. The invention also provides a particulate product obtainable by the method according to claim 18 , wherein the particles comprise (1) silicic acid, (2) boric acid, and (3) the water absorbing additive, and wherein at least 90% of the particles in the particulate product have particle sizes in the range of 0.3-5 μm. |