Device for crystallization by isentropic expansion and its use

A device for crystallization of a component from a liquid mixture comprising an elongated chamber (1) having an upper part an intermediate part and a lower part said upper part having means (46) for supplying said liquid mixture, said intermediate part having collecting means (20) for, for withdrawing a suspension of crystals of the component in a mother liquor, and said lower part having means for separation and purification of resultant crystals, means (9) for supplying a cold gaseous fluid into at least one point located below the upper part of the elongated chamber and means (22) located in the upper part of the chamber for drawing off hot gaseous fluid resulting from direct countercurrent heat exchange of the cold gaseous fluid with aid liquid mixture, said device also comprising means for shaping a descending flow of the liquid mixture such that the cold gaseous fluid that circulates upward exchanges cold directly with the mixture that is shaped, wherein means (22) for drawing off the hot gaseous fluid are connected to at least one means (24b) for recompression of said hot gaseous fluid, wherein the recompression means has an output connected to at least one heat exchanger (27), wherein the heat exchanger has an output that is connected to a turbo-expander (30), and wherein the turbo-expander has an output connected to means (31) for supplying cold gaseous fluid.