Abstract: Impure liquid media containing contaminating amounts of metallic impurities, e.g., alkaline earth metals, heavy metals and/or radioactive elements, for example industrial effluents from the nitric acidulation of rare earth concentrates, are purified by separately introducing a source of phosphorus and a source of barium into the impure medium, whereby precipitating a solid residue which comprises a barium phosphate having such contaminating metallic impurities distributed therein, and thence separating the solid residue from the liquid medium thus purified.

Abstract: Environmental pollution stemming from the industrial discharge and/or storage of water-soluble thorium compounds is avoided by converting same into essentially innocuous water-insoluble thorium phosphates, notably orthorhombic thorium phosphates, by (i) reacting such water-soluble thorium compounds, e.g., the nitrates and/or chlorides, with a base, for example aqueous ammonia, in an aqueous reaction medium, to precipitate a thorium hydroxide therein, (ii) next reacting the precipitate thus formed with a phosphating compound, e.g., phosphoric acid or a soluble phosphate salt, also in an aqueous reaction medium, to precipitate a thorium phosphate therein, and then (iii) separating such thorium phosphate precipitate.

Abstract: Yttrium is selectively separated from other rare earth values by contacting a mixed aqueous solution thereof that contains nitrate ions with a water-immiscible organic phase which includes a selective extractant for such other rare earth values, whereby such other rare earth values are selectively liquid/liquid extracted into this organic phase, the selective extractant comprising:(a) an anionic compound having the general formula (I): ##STR1## in which M is nitrogen, phosphorus or arsenic, Z is an anion, and R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be identical or different, are each an aliphatic hydrocarbon radical having from 1 to 18 carbon atoms or an aromatic radical, and(b) a substituted hydroxyquinoline having the general formula (II): ##STR2## in which R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9 and R.sub.

Abstract: The rare earth values contained in an aqueous solution of the nitrates of at least two rare earth elements are conveniently separated by first liquid/liquid extracting such aqueous nitrate solution with a liquid organic phase containing at least two P(O)R.sub.1 R.sub.2 R.sub.3 /P(O)R.sub.4 R.sub.5 R.sub.6 organophosphorus extractants.

Abstract: The rare earth values contained in an aqueous solution of the nitrates of at least two rare earth elements are conveniently separated by first liquid/liquid extracting such aqueous nitrate solution with a liquid organic phase containing a P(O)R.sub.1 R.sub.2 R.sub.3 organophosphorus extractant.

Abstract: Barium compounds containing contaminating amounts of strontium, e.g., barium salts, are effectively purified, notably into barium values suitable for conversion into specialty grade barium carbonate and titanate, by intimately contacting and liquid/liquid extracting aqueous solutions thereof with an organic solvent phase comprising at least one essentially water insoluble --CH.sub.2 --R' substituted 8-hydroxy-quinoline extractant.

Abstract: Aqueous nitric solutions of salts of at least one rare earth, and containing contaminating amounts of at least one alkaline earth cation, e.g., calcium, barium and/or radium, are conveniently purified by liquid/liquid extracting same with an organic phase which comprises a polyether extractant for said at least one alkaline earth cation, e.g., a crown ether, and whereby said at least one alkaline earth cation is selectively transferred into said organic phase.