EVALUATION OF TOE ZONE-PURIFICATlON PROCESSnAS A METHOD OF PREPARATION OF POTABLE WATER FROM SEA WATER

摘要

In the period covered by the first two stages of this investigation, much was learned concerning the segregation of dissolved salts from water during freezing. Visual observation during freezing, microscopic examination of ingots, and study of the effect of variation of certain process parameters upon segregation coefficients resulted in new understanding and control of the process. As knowledge of the crystallization process and of the various process parameters increased, and as control of the process was improved, increasingly encouraging results were obtained. In directional freezing experiments on sea water, it was found possible to prepare excellent drinking water (less than 50 ppm total salt concentration) in a two-stage process employing mechanical agitation and a low freezing rate. Even with these encouraging results, it was felt that further understanding of the phenomena which occur during freezing is necessary for the establishment of optimum conditions for segregation of salt and for the determination of the most suitable conditions for large-scale operation.