METHOD OF REMOVING SULFATE IONS FROM WASTE WATER Russian patent published in 2004 - IPC

FIELD: waste water treatment.

SUBSTANCE: invention relates to chemical methods for treating waste waters and natural water to remove sulfate ions therefrom and may be used in mining and chemical industries as well as for treatment of galvanic effluents at engineering plants. Method based on using aluminum-containing reagent followed by neutralization is characterized by that waste water, before adding reagent, is neutralized to pH 8.5-12.1 and, as reagent, amorphous-structure aluminum hydroxide recovered from acidic solution of aluminum salt is used, which reagent is mixed with neutralized waste water and mixture is additionally limed (neutralized) to pH 12.2-12.8 at continuous stirring until sulfate ions are completely transferred into solid phase. Sulfate-free water is separated from precipitate and bubbled with air or CO₂.

EFFECT: reduced process expenses on desulfatization to below 100 mg/dm³ required by maximum allowable concentration norm for discharge of water into fish-farming reservoirs.

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