Abstract: 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.

Abstract: Disclosed is a process for extracting or separating metal ions using a composition including: an ionic liquid of formula C+,?X, in which: C+ is an onium cation including at least one hydrocarbon chain R1 including from 6 to 20 carbon atoms; XP? 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 ?IL; and a phase enriched in water ?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.

Abstract: Disclosed is a process for extracting or separating metal ions using a composition including: an ionic liquid of formula C+,-X, in which: C+ is an onium cation including at least one hydrocarbon chain R1 including from 6 to 20 carbon atoms; XP? 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 ?IL; and a phase enriched in water ?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.