In addition to these ...
Published by Guyteau Bayard, Employee at Bayard desalination
In addition to these effective suggestions already proposed, one could also add the precipitation of the F ions via the cryolite, this solution supposes the addition of a little sodium chloride and aluminum. The presence in the medium of the ions F-Al 3 + and Na + will give AlF63- + 3 Na + Na3AlF6 whose solubility is insignificant. The pH may be corrected after.