Patent ID: 6251283
Filing Date: 2001-06-26
Classification: C02F,Y10S

Abstract:
A method of removing selenium in the form of selenite or selenate from a waste stream, said method comprising:contacting the waste stream with a metal salt solution to form a first mixture; andcontacting the first mixture with a first sulfate solution to form a first solid precipitate and a second solution; wherein the first sulfate forms a metal sulfate with the metal salt of the first mixture; and wherein the metal sulfate encapsulates the selenium to form the first solid precipitate; andcontacting the second solution with a second sulfate solution to form a second solid precipitate and a third solution; andremoving the first solid precipitate from the second solution prior to contacting the second solution with the second sulfate solution; andremoving the second solid precipitate from the third solution;wherein the metal salt is selected from the group consisting of a barium salt, a lead salt, and a calcium salt, and the metal salt is a bromide, chloride, or acetate; andwherein the first sulfate solution and the second sulfate solution independently comprise sodium sulfate, ferrous sulfate, sulfuric acid, or a combination thereof.