Removal from industrial wastewaters of metals that form sparingly soluble sulfides
AssigneeBASF SE
InventorJoerg Schwarzbach
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Abstract
Metals that form sparingly soluble sulfides are removable from industrial wastewaters by adding a precipitant comprising a suspension obtained by mixing sulfur, an iron(II) salt, water and a base, adjusting the wastewater pH to >4, and separating off the resulting sulfidic precipitate in a conventional manner.
Claims6
A process for removing metals that form sulfides which precipitate from industrial wastewaters by adding a precipitant and subsequently separating off the resulting precipitate, which consists essentially of adding as precipitant a suspension having a pH .gtoreq.5, obtained by mixing sulfur, from 0.5 to 10 mol an iron(II) salt, for each mol of sulfur, water and a base, wherein iron(II) sulfide is present in said suspension in equilibrium with iron(II) hydroxides adjusting the wastewater pH to .gtoreq.4, to form a sulfidic precipitate containing said metals and separating off said sulfidic precipitate.
Dependencies are inferred from the claim text.