Separation of fresh water from aqueous solutions

Claim 1

IN THE PROCESS OF EFFECTING RECTIFICATION OF AN AQUEOUS SOLUTION INTO RELATIVELY RICH AND LEAN PORTIONS BY A FIRST STEP OF PARTIALLY FREEZING THE AQUEOUS SOLUTION BY REMOVAL OF HEAT ENERGY THERFROM TO FORM ICE, A SECOND STEP OF SEPARATING THE ICE FROM THE MOTHER LIQUOR, AND A THIRD STEP OF MELTING THE SEPARATED ICE BY THE ADDITION OF HEAT ENERGY SO THAT THE MOTHER LIQUOR AND THE MELTED ICE RESPECTIVELY CONSTITUTE THE RELATIVELY RICH AND LEAN PORTIONS; THE IMPROVEMENT COMPRISING CONDUCTING THE FIRST STEP BY MAINTAINING A HEAT EXCHANGE RELATION BETWEEN THE AQUEOUS SOLUTION AND AN AT LEAST PARTIALLY FROZEN MATERIAL WHILE ALSO MAINTAINING SUCH MATERIAL UNDER A PRESSURE SUCH THAT THE PREVAILING LIQUID-SOLID TRANSITION TEMPERATURE THEREOF IS LESS THAN THE CURRENTLY PREVAILING FREEZING TEMPERATURE OF THE AQUEOUS SOLUTION TO THEREBY MELT AT LEAST A PORTION OF SAID MATERIAL AND CONDUCTING THE THIRD STEP BY MAINTAINING A HEAT EXCHANGE RELATION BETWEEN THE SEPARATED ICE AND AT LEAST A PART OF THE PORTION OF THE MATERIAL MELTED IN THE FIRST STEP WHILE ALSO MAINTAINING THE LATTER UNDER A PRESSURE SUCH THAT THE PREVAILING LIQUID-SOLID TRANSITION TEMPERATURE THEREOF IS HIGHER THAN THE CURRENTLY PREVAILING LIQUIDSOLID TRANSITION TEMPERATURE OF THE SEPARATED ICE.