Patent ID: 11905180
Assignee: TORAY INDUSTRIES, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC B  C  H  Y | IPC B  C

Claim 23:
24. The method for recovering a rare metal salt according to claim 12, wherein
the reverse osmosis membrane used in the concentration step comprises a base material, a porous support layer on the base material, and a separation function layer on the porous support layer,
the separation function layer has a fold structure in which convex portions and concave portions are repeated, the convex portion and the concave portion being formed of a thin membrane of a crosslinked aromatic polyamide, and
a reverse osmosis membrane in which, among the convex portions, a proportion of a convex portion having a deformation amount of 2.5 nm or less when the convex portion is pressed in a sulfuric acid aqueous solution having a pH of 1 with a force of 5 nN is 0.50 times or more as large as a proportion of a convex portion having a deformation amount of 2.5 nm or less when the convex portion is pressed in pure water with a force of 5 nN is used.