The use of a synergistic mixture of extractants for extracting at least one rare earth element from an aqueous medium comprising phosphoric acid. The mixture comprises: —a first extractant of formula (I):

##STR00001##

wherein R.sub.1 and R.sub.2, which are identical or different, represent a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 6 to 12 carbon atoms, or a phenyl group optionally substituted by a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 1 to 10 carbon atoms; and —a second extractant of formula (II):

##STR00002##

in which R.sub.3 represents a linear or branched alkyl group, comprising from 6 to 12 carbon atoms.

Use of the synergistic mixture in the treatment of phosphate minerals with a view to recovering the rare earth elements contained in the minerals.

Provided is a method of extracting and separating zirconium and hafnium from hydrochloric acid medium, which relates to the technical field of fine separation of substance. Primarily, extraction is performed to acidic raw liquid containing zirconium compounds by a synergistic extraction system consisting of DIBK and phosphonic acids extraction agent, so that the zirconium goes to the aqueous phase and the hafnium goes to the organic phase, thus the separation is achieved. No toxic substance is involved throughout the process, so clean production is achieved.

The use of a synergistic mixture of extractants for extracting at least one rare earth element from an aqueous medium comprising phosphoric acid. The mixture comprises: a first extractant of formula (I): ##STR00001##
wherein R.sub.1 and R.sub.2, which are identical or different, represent a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 6 to 12 carbon atoms, or a phenyl group optionally substituted by a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 1 to 10 carbon atoms; anda second extractant of formula (II): ##STR00002##
in which R.sub.3 represents a linear or branched alkyl group, comprising from 6 to 12 carbon atoms. Use of the synergistic mixture in the treatment of phosphate minerals with a view to recovering the rare earth elements contained in the minerals.