Method for removing mercury and selenium from sulfate-containing waste water

摘要

The invention is directed to a method for the removal of mercury and selenium from sulfate-containing waste water. The method may include the following steps: a) a mercury- and selenium-contaminated waste water with a known sulfate concentration is provided, b) barium sulfate (BaSO₄) is precipitated from the provided waste water by the addition of a predefined amount of Ba²⁺ ions to the waste water, c) BaSO₄ (if necessary together with other solids) is separated obtaining a low-solid waste water, d) the low-solid waste water is fed to an ion exchanger for the removal of mercury obtaining a waste water with a reduced mercury content, e) selenium and/or selenium compounds are removed from the waste water with the reduced mercury content and f) a sulfate-containing solution or solid is added to the waste water with a reduced selenium and/or selenium compound content in order to precipitate barium sulfate.