Conversion

The natural uranium is purified then transformed into uranium hexafluoride (UF6) to allow gas enrichment at low temperature.
This conversion is carried out in two stages: the first one consists in transforming the uranium concentrate (U3O8) into uranium tetrafluoride (UF4) by dissolution then hydrofluorination; the second one is to transform the UF4 into UF6 by the addition of fluorine.