The invention relates to a device (30) and a method (1) for work-up of an amino acid salt solution (3), as an absorption agent for carbon dioxide from a flue gas of a combustion process, that has been contaminated with carbon dioxide (2), and comprises a reaction process (100), a subsequent filtration process (200) and a subsequent dissolving process (300). In the reaction process (100), carbon dioxide (2) is introduced into the amino acid salt solution (3), and the amino acid salt solution (3) is cooled. Crystalline carbonate (4) and crystalline amino acid (7) then precipitates out. In the filtration process (200), the crystalline carbonate (4) and the crystalline amino acid (7) are filtered out. In the dissolving process (300), the crystalline carbonate (4) and the crystalline amino acid (7) are dissolved in a solvent (9) and a worked-up amino acid salt solution (15) is thereby obtained.