| 摘要 |
The invention relates to a method for purifying contaminated aqueous solutions, by precipitation with known precipitation reagents, the precipitation process being carried out in at least two stages. The method is characterized in that precipitation is carried out in at least the first stage as a sulphide precipitation process in an acid environment and in at least one subsequent stage in a more alkaline environment, with the aid of metal ions and/or metal hydroxide. The precipitate present in the aqueous solution subsequent to the precipitation process effected in a more alkaline environment is removed, essentially completely, and recycled. Precipitatable contaminants present in the incoming aqueous solution are removed in the form of precipitate obtained in an acid environment and the solution freed from precipitate is removed from the last more-alkaline stage. |
