TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: In the process, before the step (b), the acidic alkali metal silicate solution from the step (a) is further contacted with a resin, which has chelate-forming functional groups with a binding affinity of 2 or higher valence metal ion. The process further comprises aging the acidic alkali metal silicate solution at 10-100 degrees C for 0-48 hours. The water-soluble alkali metal silicate is dissolved to obtain a solution, which contains 1-8 wt.% of silica. Preferred Components: The chelating functional group is phosphonic acid group, optionally substituted aminophosphonic acid group, sulfonic acid group and/or carboxyl group. The water soluble alkali metal silicate is a sodium water glass or potassium water glass, where the molar ratio of silica to sodium water glass or potassium water glass is 4.5:1.5. The acidifying agent is hydrochloric acid, phosphoric acid, nitric acid, sulfuric acid, chlorosulfonic acid, sulfuryl chloride and/or perchloric acid. The acidic aqueous solution of the water-soluble alkali metal silicate comprises hydrogen peroxide. The aqueous silicic acid solution: has a pH of 1-5; and is a clear or a colloidal solution and stabilized by alkalization.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The mixing process in the step (a) takes place using a static or dynamic mixer. EXAMPLE - Sulfuric acid (255 g) and hydrogen peroxide (1.6 g) were stirred and water glass (307 g) (comprising 28.9 wt.% of silica and 8.97 wt.% of sodium oxide) was added to obtain a clear, yellow-orange colored solution with a pH of less than or equal to 1. The obtained acidic aqueous alkali metal silicate solution was further passed over Lewatit TP260 (RTM: Weakly acidic cation exchange resin with chelating amino methyl phosphonic acid groups). Subsequently, Lewatit MonoPlus S100 (RTM: Strongly acidic, gelular cation exchange resin) and Lewatit MonoPlus M600 (RTM: Strongly basic, gelular anion exchange resin) were added to the acidic aqueous alkali metal silicate solution to obtain aqueous silicic acid solution with a pH of 3-5. The pH of the obtained silicic acid solution was adjusted to 8-10.5 by adding aqueous potassium hydroxide solution and heated to 90 degrees C. At this temperature, highly pure aqueous silicic acid solution and potassium hydroxide solution in a constant molar ratio were added. The obtained solution was ultrafiltered to obtain the colloidal silica sol.