A method for producing and using an ultrapure colloidal silica dispersion is disclosed. The ultrapure colloidal silica dispersion has less than 200 ppb of each trace metal impurity disposed therein, excluding potassium and sodium, and less than 2 ppm residual alcohol. The method comprises dissolving a fumed silica in an aqueous solvent comprising an alkali metal hydroxide to produce an alkaline silicate solution, removing the alkali metal via ion exchange to generate a silicic acid solution, adjusting temperature, concentration and pH of said silicic acid solution to values sufficient to initiate nucleation and particle growth, and cooling the silicic acid solution at a rate sufficient to produce the colloidal silica dispersion.