The invention relates to alkenyl(perfluoroalkyl)phosphinic acids, to the preparation and intermediates thereof, to the use thereof as monomers for the preparation of oligomers and/or polymers, to the corresponding oligomers/polymers, to the corresponding support materials comprising the oligomers/polymers, and to the use thereof as ion exchangers, as catalysts or extraction medium and corresponding salts thereof.

A method for producing mixed metal salts containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a precipitation step of neutralizing an extracted residual liquid obtained in the Al removal step under conditions where a pH is less than 10.0, to precipitate mixed metal salts comprising a metal salt of manganese and a metal salt of at least one of cobalt and nickel.

The invention relates to alkenyl(perfluoroalkyl)phosphinic acids, to the preparation and intermediates thereof, to the use thereof as monomers for the preparation of oligomers and/or polymers, to the corresponding oligomers/polymers, to the corresponding support materials comprising the oligomers/polymers, and to the use thereof as ion exchangers, as catalysts or extraction medium and corresponding salts thereof.

Provided are a separation recovery method of metal ions and an acidic metal extractant used in the separation recovery method. The separation recovery method includes: extracting and separating two or more kinds of metal ions belonging to different groups by mixing a water phase and an oil phase with each other, the water phase including two or more kinds of metal ions belonging to different groups among metal ions belonging to Groups 9 and 10 of the fourth to sixth periods in a periodic table, and the oil phase including an acidic metal extractant having two or more coordinating functional groups selected from a carboxy group, a phosphate group, a phosphonate group, a sulfonate group, and a sulfinate group.