Method for recovering Cr from a pickling bath of an aqueous solution containing sulphate and Cr from a pickled metal, the method including: -forming an aqueous two-phase system from a portion of the pickling bath and a polymer including an unhindered ether function, the proportion of polymer in the ternary mixture including the pickling bath, considered to be a unique chemical component, water and polymer, ranging between the line of the equation «weight % of polymer=100%−weight % of pickling bath» and the binodal curve of the pickling bath/polymer mixture, the two-phase aqueous system including polymer and non-polymer phases;—separating the respective phases;—allowing precipitates containing Cr to form in the polymer phase;—carrying out solid/liquid separation of the polymer phase to separate the polymer and the precipitates containing Cr;—and processing the precipitates to recover the Cr. A facility is also disclosed.

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 invention relates to a method for the recovery of palladium from an aqueous solution, comprising the steps of: (A) providing a dispersion comprising an aqueous dispersing phase comprising palladium(II), at least one non-ionic surfactant and at least one compound bearing a beta-dithiocarbonyl group, so as to form a hydrophobic complex of palladium(II) with the compound bearing a beta-dithiocarbonyl group; (B) heating the dispersion resulting from step (A) to a temperature at least equal to its cloud point so as to obtain the phase separation between the aqueous dispersing phase and a dispersed phase rich in surfactant comprising at least a part of said hydrophobic complex; (C) separating the dispersed phase rich in surfactant from the aqueous dispersing phase resulting from step (B); and (D) recovering the hydrophobic complex of palladium(II) with the compound bearing a beta-dithiocarbonyl group.

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.

Provided are a method for recovering gold, in which gold is recovered from a solution containing a gold cyano complex using a crosslinked resin containing a vinyl amine unit, by which gold can be efficiently recovered from the solution not only in a case (A) where a concentration of the gold cyano complex in the solution is low but also in a case (B) where another metal is dissolved in the solution; a method for recovering gold, in which the crosslinked resin and the solution are brought into contact with each other to separate the crosslinked resin and the solution from each other, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B); and a gold recovery facility comprising: a container inside which the crosslinked resin is accommodated in a flowable manner; and a device which feeds the solution to the container, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B).

The invention concerns a method for preparing an aqueous mineral suspension from an aqueous metal ore residue into which a polymer (P) is introduced having a molecular mass Mw measured by GPC ranging from 2,000 to 20,000 g/mol and prepared by radical polymerisation of at least one anionic monomer (M). The invention also concerns the suspension produced, the Brookfield viscosity of which is lower than 1,800 mPa.Math.s or the yield point of which is lower than 80 Pa.

A method can prepare an aqueous mineral suspension from an aqueous metal ore residue into which there is introduced a polymer (P) having a molecular weight Mw measured by GPC of from 100,000 to 3.106 g/mol and prepared by free radical polymerization of at least one anionic monomer (m). The suspension produced may have a Brookfield viscosity greater than 2,000 mPa.Math.s and/or a flow threshold of greater than 40 Pa.

Provided are a method for recovering gold, in which gold is recovered from a solution containing a gold cyano complex using a crosslinked resin containing a vinyl amine unit, by which gold can be efficiently recovered from the solution not only in a case (A) where a concentration of the gold cyano complex in the solution is low but also in a case (B) where another metal is dissolved in the solution; a method for recovering gold, in which the crosslinked resin and the solution are brought into contact with each other to separate the crosslinked resin and the solution from each other, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B); and a gold recovery facility comprising: a container inside which the crosslinked resin is accommodated in a flowable manner; and a device which feeds the solution to the container, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B).

A hydrometallurgical solvent extraction method includes mixing an aqueous metal ion solution with an organic solution of metal extraction reagent to form a mixture, and allowing the aqueous metal ion solution and organic solution to phase separate from the mixture; wherein prior to mixing the aqueous metal ion solution and the organic solution, a water-soluble or water-dispersible polymer comprising pendant sulfonic acid or sulfonate salt groups selected from the group consisting of sulfonated polystyrene; an addition polymer including at least one of styrene-4-sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid; naphthalene sulfonic acid-formaldehyde condensate; lignosulfonate; salts thereof; and mixtures thereof, is added to the aqueous metal ion solution, the organic solution, or to both the aqueous metal ion solution and the organic solution. The water-soluble or water-dispersible polymer can also be added simultaneously with or after mixing of the aqueous metal ion solution and the organic solution.

The present invention is in the field of surfactants to extract a platinum group metal or gold, in particular palladium, from organic compositions. In particular, the invention concerns the use of surfactants to back-extract a platinum group metal or gold, in particular palladium, from organic compositions further comprising an extractant of said platinum group metal or gold, in particular palladium from an aqueous solution.