An extractant which makes it possible to extract both light rare earths and heavy rare earths from an aqueous phosphoric acid solution, likely to be present in this solution, and which is characterised in that it comprises: a compound of formula (I) below: ##STR00001##
wherein R1 and R2, identical or different, are a hydrocarbon group, saturated or unsaturated, linear or branched, in C6 to C12; R3 is a hydrocarbon group, in C1 to C6, or a hydrocarbon group, saturated or unsaturated, monocyclic, in C3 to C8; R4 and R5, identical or different, are a hydrogen atom or a hydrocarbonate group, saturated or unsaturated, linear or branched, in C2 to C8; and a surfactant. Applications of this extractant include treatment of aqueous solutions from the leaching of natural phosphates by sulphuric acid and aqueous solutions from the leaching of urban minerals by phosphoric acid, in view of making profitable use of the rare earths present in these solutions.

An extractant which makes it possible to extract both light rare earths and heavy rare earths from an aqueous phosphoric acid solution, likely to be present in this solution, and which is characterised in that it comprises: a compound of formula (I) below: ##STR00001##
wherein R1 and R2, identical or different, are a hydrocarbon group, saturated or unsaturated, linear or branched, in C6 to C12; R3 is a hydrocarbon group, in C1 to C6, or a hydrocarbon group, saturated or unsaturated, monocyclic, in C3 to C8; R4 and R5, identical or different, are a hydrogen atom or a hydrocarbonate group, saturated or unsaturated, linear or branched, in C2 to C8; and a surfactant. Applications of this extractant include treatment of aqueous solutions from the leaching of natural phosphates by sulphuric acid and aqueous solutions from the leaching of urban minerals by phosphoric acid, in view of making profitable use of the rare earths present in these solutions.

The present disclosure provides system and method embodiments for extracting and separating rare earth elements (REEs) from various starting materials and sources. The system and method embodiments disclosed herein facilitate efficient REE extraction, separation, and/or isolation, even when the REEs are present in a starting material at a relatively low level compared to undesirable metals co-present in the starting material. In at least some examples, the disclosed system and method embodiments may be used to recover one or more REEs from coal derived acid mine drainage.

The present disclosure provides system and method embodiments for extracting and separating rare earth elements (REEs) from various starting materials and sources. The system and method embodiments disclosed herein facilitate efficient REE extraction, separation, and/or isolation, even when the REEs are present in a starting material at a relatively low level compared to undesirable metals co-present in the starting material. In at least some examples, the disclosed system and method embodiments may be used to recover one or more REEs from coal derived acid mine drainage.

A method for extracting rare earth elements (REEs) from a REE hyperaccumulator, including: subjecting the REE hyperaccumulator to microwave-assisted digestion to obtain a REE extract; subjecting the REE extract to absorption with a chelating resin and elution to obtain a purified REE solution; and subjecting the purified REE solution to precipitation and calcination to obtain high-purity rare earth compound.

A method for extracting rare earth elements (REEs) from a REE hyperaccumulator, including: subjecting the REE hyperaccumulator to microwave-assisted digestion to obtain a REE extract; subjecting the REE extract to absorption with a chelating resin and elution to obtain a purified REE solution; and subjecting the purified REE solution to precipitation and calcination to obtain high-purity rare earth compound.

The present application provides a method for recovering metal from metal-containing material by leaching, the method comprising providing aqueous solution containing leaching agent precursor, providing one or more source(s) of external energy comprising a source of electric current connected to one or more non-metallic electrode(s) comprising carbon material(s) selected from graphite, graphene and derivatives thereof, and carbon nanomaterial(s) selected from carbon nanofibers, carbon nanotubes and carbon nanobuds, treating the aqueous solution with the external energy, which is electric current providing electrochemical reactions, to form hydrogen peroxide from oxygen in the aqueous solution, reacting the leaching agent precursor with the formed hydrogen peroxide to form a leaching agent and to obtain a leaching solution, providing metal-containing material, reacting the metal-containing material with the leaching solution to obtain soluble metal complexes, and recovering the soluble metal complexes. The present application also discloses a device for recovering metal from metal-containing material by leaching.

The invention comprises a method and apparatus for generating a rare earth from a rare earth oxide, comprising the sequential steps of: (1) reducing temperature about the rare earth oxide to less than zero degrees Celsius; (2) reducing pressure to boil off contaminant water in a powder sample of the rare earth oxide at a molecular escape velocity not disturbing the powdered rare earth oxide; and (3) heating the rare earth oxide to greater than 1000° C. in the presence hydrogen gas while optionally: (1) collecting and determining mass of a water product to determine a consumption mass of the starting hydrogen gas in a main reaction process using the equation RE.sub.2O.sub.3+3H.sub.2.fwdarw.2RE+3H.sub.2O, wherein “RE” comprises at a rare earth and (2) injecting replacement hydrogen gas into the main reaction chamber up to the consumption mass.

The invention comprises a method and apparatus for generating a rare earth from a rare earth oxide, comprising the sequential steps of: (1) reducing temperature about the rare earth oxide to less than zero degrees Celsius; (2) reducing pressure to boil off contaminant water in a powder sample of the rare earth oxide at a molecular escape velocity not disturbing the powdered rare earth oxide; and (3) heating the rare earth oxide to greater than 1000° C. in the presence hydrogen gas while optionally: (1) collecting and determining mass of a water product to determine a consumption mass of the starting hydrogen gas in a main reaction process using the equation RE.sub.2O.sub.3+3H.sub.2.fwdarw.2RE+3H.sub.2O, wherein “RE” comprises at a rare earth and (2) injecting replacement hydrogen gas into the main reaction chamber up to the consumption mass.

Apparatus and methods for lithium extraction from aqueous sources are described herein. Divalent ions are removed using staged membrane separation. The aqueous source is subjected to a solvent extraction process that extracts lithium. Aqueous and organic phases of streams produced by the solvent extraction process are separated using electrical and/or gas flotation separation. The solvent is de-complexed to unload lithium. Streams produced by the de-complexing may be subjected to electrical and/or gas flotation separation. Solvent de-complexing can be performed using an electrical separator. Aqueous streams are pH adjusted for return to the environment.