A method for purifying lutetium includes providing a solid composition comprising ytterbium and lutetium and subliming or distilling ytterbium from the solid composition at a temperature of about 1196° C. to about 3000° C. to leave a lutetium composition comprising a higher weight percentage of lutetium than was present in the solid composition.

A method for purifying lutetium includes providing a solid composition comprising ytterbium and lutetium and subliming or distilling ytterbium from the solid composition at a temperature of about 1196° C. to about 3000° C. to leave a lutetium composition comprising a higher weight percentage of lutetium than was present in the solid composition.

A method for extracting a rare earth metal from a mixture of one or more rare earth metals, said method comprising contacting an acidic solution of the rare earth metal with a composition which comprises an ionic liquid to form an aqueous phase and a non-aqueous phase into which the rare earth metal has been selectively extracted.

Lithium extractant compounds having the following structure:

##STR00001##

wherein: R.sup.a and R.sup.b are independently selected from the group consisting of hydrocarbon groups (R), —OR, —NRR′, —SR, —SO.sub.2R, —SO.sub.2NR.sub.2, —C(O)R, —C(O)OR, —C(O)NRR′, —C(S)OR, —C(O)SR, and —C(S)NRR′; R′ is selected from R′ groups, wherein R′ is selected from H and R groups; X is O or OH; Y is C or N, wherein, when Y is N, then R.sup.a is R. Also described are hydrophobic water-insoluble solutions containing at least one extractant compound of Formula (1). Also described is a method for extracting lithium from an aqueous solution by contacting the aqueous solution with the hydrophobic solution, and optional stripping of lithium from the hydrophobic solution by contacting the hydrophobic solution with an aqueous stripping solution.

Lithium extractant compounds having the following structure:

##STR00001##

wherein: R.sup.a and R.sup.b are independently selected from the group consisting of hydrocarbon groups (R), —OR, —NRR′, —SR, —SO.sub.2R, —SO.sub.2NR.sub.2, —C(O)R, —C(O)OR, —C(O)NRR′, —C(S)OR, —C(O)SR, and —C(S)NRR′; R′ is selected from R′ groups, wherein R′ is selected from H and R groups; X is O or OH; Y is C or N, wherein, when Y is N, then R.sup.a is R. Also described are hydrophobic water-insoluble solutions containing at least one extractant compound of Formula (1). Also described is a method for extracting lithium from an aqueous solution by contacting the aqueous solution with the hydrophobic solution, and optional stripping of lithium from the hydrophobic solution by contacting the hydrophobic solution with an aqueous stripping solution.

The present application relates to methods for leaching and extraction of precious metals. For example, the present application relates to methods of leaching gold, palladium and/or platinum from a substance comprising gold, palladium and/or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.

The present application relates to methods for leaching and extraction of precious metals. For example, the present application relates to methods of leaching gold, palladium and/or platinum from a substance comprising gold, palladium and/or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.

Disclosed is a process for extracting or separating metal ions using a composition including: an ionic liquid of formula C.sup.+,−X, in which: C.sup.+ is an onium cation including at least one hydrocarbon chain R.sup.1 including from 6 to 20 carbon atoms; X.sup.P− is an anion of charge p, the ionic liquid having a solubility in water at 20° C. of at least 10 g/l; an acid; and water. The composition includes two liquid phases: a phase enriched in ionic liquid ϕ.sub.IL; and a phase enriched in water ϕ.sub.w, the pH of which is less than or equal to 4.7. The composition is useful for extracting a metal ion from an acidic aqueous medium including a metal ion, for separating metal ions from an aqueous medium including at least two metal ions or for purifying an acidic aqueous solution including a metal ion.

Disclosed is a process for extracting or separating metal ions using a composition including: an ionic liquid of formula C.sup.+,−X, in which: C.sup.+ is an onium cation including at least one hydrocarbon chain R.sup.1 including from 6 to 20 carbon atoms; X.sup.P− is an anion of charge p, the ionic liquid having a solubility in water at 20° C. of at least 10 g/l; an acid; and water. The composition includes two liquid phases: a phase enriched in ionic liquid ϕ.sub.IL; and a phase enriched in water ϕ.sub.w, the pH of which is less than or equal to 4.7. The composition is useful for extracting a metal ion from an acidic aqueous medium including a metal ion, for separating metal ions from an aqueous medium including at least two metal ions or for purifying an acidic aqueous solution including a metal ion.

A method for extracting a rare earth metal from a mixture of one or more rare earth metals, said method comprising contacting an acidic solution of the rare earth metal with a composition which comprises an ionic liquid to form an aqueous phase and a non-aqueous phase into which the rare earth metal has been selectively extracted.