A device for crystallization of a component from a liquid mixture comprising a chamber, a first conduit connected to said chamber for supplying said mixture, a second conduit connected to and in connection with said chamber for introducing cold gas, a third conduit for withdrawing warmed gas from said crystallizer, a turbo-expander for cooling gas withdrawn from said chamber, and a fourth conduit Icading from the turbo-expander to said chamber. The device has particular application for the crystallization of paraxylene.