A device and method for separating off carbon dioxide is provided, including an absorption unit, desorption unit assigned thereto and a separation unit for separating off salts from a scrubbing solution. The absorption and desorption units are connected to each other via a first conduit for a regenerated scrubbing solution and a second conduit for a loaded scrubbing solution. The separation unit includes a crystallizer for forming salt crystals and a first separator unit on the downstream side for separating off salt crystals. A separation unit is provided for separating off salts from a scrubbing solution, having a crystallizer and a first separator unit downstream thereof. The crystallizer has a crystallization chamber for forming salt crystals and a countercurrent classifier for separating salt crystals according to particle size. A first branch conduit is connected to the crystallization chamber, which opens out into the countercurrent classifier via a second separator unit.