Abstract: The invention relates to a process for the removal of fluoride from waste water in the form of a slightly soluble salt by mixing the waste water with a reagent. According to the invention the fluoride containing waste water is thoroughly mixed with the water soluble reagent at a suitable pH in a reactor of the fluidized bed type, which is provided with an appropriate seed material, on which the fluoride salt crystallizes out, whereby the thus obtained pellets comprising the seed material with the crystalline fluoride salt, is removed from and new seed material is added to the reactor from time to time. According to the present process as reagent CaCl.sub.2 is used, whereas the pH is adjusted to an appropriate value.

Abstract: Process for the removal of metals, in particular heavy metals and strontium, from waste water in the form of their sulfide by mixing the waste water with a water soluble sulfide. According to the invention the metal containing waste water is thoroughly mixed with the water soluble sulfide at a suitable pH in a reactor of the fluidized bed type, which is provided with an appropriate bed material, on which the metal sulfide crystallizes out, whereby the thus obtained bed material provided with crystalline metal sulfide is removed from and new bed material is added to the reactor from time to time. Usually as water soluble sulfide an alkali metal sulfide or alkali metal hydrogen sulfide or ammonium sulfide or FeS is used, whereas the use of sodium sulfide, sodium hydrogen sulfide, potassium sulfide or potassium hydrogen sulfide is preferred. According to the present process a.o. the following metals: Ni, Sr, Zn, Cu, Fe, Ag, Pb, Cd, Hg, Co, Mn, Te, Sn, In, Bi or Sb may be removed.

Abstract: Process for removing Sr and heavy metals from water in particular from waste water by throughly mixing it with a solution of an alkali metal carbonate and/or hydrogen carbonate in a reactor containing a fluidized bed of suitable bed material. The obtained heavy metal carbonate crystals crystallize onto said bed material and the obtained heavy metal carbonate crystals in granular form are removed from the reactor from time to time.The heavy metals which may be removed are Ni, Zn, Cu, Fe, Ag, Pb, Cd or Hg.