METHOD FOR HIGHLY CONCENTRATING AQUEOUS SOLUTIONS

The invention refers to a method for highly concentrating aqueous solutions containing thermally sensitive organic constituents and with or without mineral constituents, wherein firstly, a major portion of the water is extracted by means of membrane filtration from the solution for pre-concentration and is discharged from the process and the solution which is pre-concentrated in this way is then subjected to a freeze concentration procedure, in which, in the form of separated ice crystallisate, further water is extracted from the solution. In order to provide the purest possible, qualitatively high-grade concentrate of the organic constituents and to ensure the highest possible yield with the lowest possible level of plant and operational outlay it is suggested that that concentration is effected in the freeze concentration procedure until a viscosity of the mother solution of at least 0.0002m 2 /s is achieved, and in that the separated ice crystallisate from the freeze concentration with the mother solution adhering thereto as a suspension is returned to the membrane filtration upstream of the membrane filtration or after melting of the ice crystallisate. An installation for carrying out this method shall also be proposed.