| abstract |
The invention provides a method for reducing the sodium content of a water containing dissolved sodium ions, in particular a water with a sodium ion content of at least 100 ppm. Examples of waters are effluents, such as acid mine drainage and river waters. The method includes the steps of: (i) Removing magnesium, calcium and sodium ions from water by contacting water with a cation exchange resin (s) in order to capture sodium, calcium and sodium ions magnesium present there; (ii) Treat the cation exchange resin (s) of step (i) with nitric acid in order to produce an eluent containing sodium ions, calcium ions, magnesium ions, nitrate ions and nitric acid ; (iii) Add a carbonate to the eluent in order to precipitate calcium and magnesium ions such as calcium and magnesium carbonates; (iv) Separate the precipitated carbonates from the eluent; and (v) Treat the eluent of step (iv) in order to obtain a potassium and / or sodium nitrate product. |