Patent ID: 8597521

Claim:
A method for removing silica from an aqueous brine solution that comprises silica, the method comprising the steps of: providing an aqueous brine solution that comprises silica and an iron (II) salt; oxidizing the iron (II) salt to iron (III) hydroxide, said oxidizing step comprises sparging the aqueous brine solution with air; maintaining the pH of the aqueous brine solution at between about 4.5 and 5.5; contacting the silica and the iron (III) hydroxide for a time sufficient for the silica to attach to the iron (III) hydroxide and form a silica/iron precipitate; separating the silica/iron precipitate from the aqueous brine solution; recovering an aqueous product stream from the separation step, said aqueous product stream having a reduced silica concentration relative to the aqueous brine solution; maintaining the pH of the aqueous product stream at between about 4 and 7; supplying the aqueous product stream to a column charged with activated alumina at a pH of between about 4 and 7 such that silica present in the aqueous product stream selectively binds to the activated alumina; and recovering a column product stream having a silica concentration of less than about 15 ppm.