Purification of hydrofluoric acid etching solutions with weak anion exchange resins
AssigneeCorning Glass Works
InventorsYao-Sin Su, Ken F. Sugawara
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Abstract
A method for purifying a spent hydrofluoric acid etching solution containing siliceous by-products which comprises treating the solution with a weak anion exchange resin of the polyamine type to remove SiF.sub.6.sup.= ions therefrom is described. The anion exchange resin may be regenerated with aqueous NaOH.
Claims2
A method for purifying a spent hydrofluoric acid glass etching solution containing up to about 13% HF by weight and containing fluosilicic acid by removing SiF.sub.6.sup.= ions therefrom which comprises the steps of treating said spent solution with a weak anion exchange resin of the polyamine type in the fluoride salt form to remove said SiF.sub.6.sup.= ions, thereafter regenerating the weak anion exchange resin with an aqueous solution of NaOH and then converting the regenerated weak anion exchange resin back to the fluoride salt from.
Dependencies are inferred from the claim text.