Provided is a method for efficiently separating and recovering tungsten and other valuable(s) from at least one valuable containing tungsten. The present invention relates to a method for recovering at least one valuable containing tungsten, comprising subjecting a raw material mixture comprising at least one valuable containing tungsten to electrolysis using an electrolytic solution containing at least one alcohol amine to dissolve tungsten in the electrolytic solution, electrodeposit a part of the valuable(s) onto a cathode used for the electrolysis and separate at least one valuable other than the valuable(s) electrodeposited onto the cathode as a residue in the electrolytic solution, and then separating and recovering each of the residue and the valuable(s) electrodeposited onto the cathode.

Provided is a system for efficiently recovering trace metal from a large amount of a raw material, such as when trace metal is recovered from nickel oxide ore. This ion exchange resin has, on a carrier, an amide derivative represented by the following general formula. In the formula, R1 and R2 represent the same or different alkyl groups, R3 represents a hydrogen atom or an alkyl group, and R4 represents a hydrogen atom or an arbitrary group, other than an amino group, bonded to carbon as an amino acid. The amide derivative is preferably a glycinamide derivative. The carrier preferably includes a primary amine and/or a secondary amine.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of alkaline earth elements. The lixiviant can be regenerated and recycled for use in subsequent iterations of the process. Multiple alkaline earth elements can be recovered from a sample in parallel or in serial applications of the disclosed methods.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of alkaline earth elements. The lixiviant can be regenerated and recycled for use in subsequent iterations of the process. Multiple alkaline earth elements can be recovered from a sample in parallel or in serial applications of the disclosed methods.

Methods and compositions are described in which amine-based compounds are utilized in the recovery of rare earth elements from solution. The rare earth elements are recovered selectively and sequentially.

Hydrometallurgical compositions are described in which organic amine-based lixiviants and organic amine-based pre-lixiviants are utilized in the selective recovery of rare earth elements. The lixiviant species can be regenerated in situ, permitting the organic amine to be used in substoichiometric amounts.

Provided is a system for efficiently recovering trace metal from a large amount of a raw material, such as when trace metal is recovered from nickel oxide ore. This ion exchange resin has, on a carrier, an amide derivative represented by the following general formula. In the formula, R1 and R2 represent the same or different alkyl groups, R3 represents a hydrogen atom or an alkyl group, and R4 represents a hydrogen atom or an arbitrary group, other than an amino group, bonded to carbon as an amino acid. The amide derivative is preferably a glycineamide derivative. The carrier preferably includes a primary amine and/or a secondary amine.

Provided are a platinum-group metal recovery agent represented by the following general Formula (1) and a platinum-group metal recovery method for recovering platinum from a hydrochloric acid solution containing platinum using the platinum-group metal recovery agent. (In Formula (1), X is a methylene group, an oxygen atom, or an ethylene group; n is 3 when X is a methylene group; and n is 2 when X is an oxygen atom or an ethylene group.)

##STR00001##

Provided are a metal extractant for extracting metal ions present in a water phase to an oil phase, and a separation recovery method of metal ions. In the metal extractant, nitrogen atoms positioned at both terminals of a molecular chain forming the metal extractant do not form a carbamoyl bond and include an unsubstituted hydrocarbon group and a group including and any coordinating functional group in a group G1 of coordinating functional groups below as a coordinating functional group (a) for metal ions to be extracted, or include an unsubstituted hydrocarbon group. The separation recovery method includes mixing an oil phase including the metal extractant and a water phase including plural kinds of metal ions.

Rare earth extractant compounds having the following structure: ##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently selected from alkyl groups containing 1-30 carbon atoms and optionally containing an ether or thioether linkage connecting between carbon atoms, provided that the total carbon atoms in R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is at least 12; R.sup.5 and R.sup.6 are independently selected from hydrogen atom and alkyl groups containing 1-3 carbon atoms; and provided that at least one of the conditions (i)-(iv) apply as follows: presence of a distal branched group in at least one of R.sup.1-R.sup.4 (condition i), asymmetry in R.sup.1-R.sup.4 (condition ii), presence of amine-containing ring (condition iii), or presence of lactam ring (condition iv). Also described are hydrophobic water-insoluble solutions containing at least one extractant compound of Formula (1), as well as method for extracting rare earth elements from aqueous solution by contacting the aqueous solution with the water-insoluble solution.