In Japan, mainly method of production of salt is two species at present, one is ion exchange membrane method, another is sun breaching method. Ion exchange membrane method has advantages as follows； large-scale production, short processing time, labor saving, by mechanizing all process. All process have carried out indoors, its lot area is small, this method is not affected by weather conditions. Disadvantage is that this method strongly depends on electric energy. Sun breaching method has advantages that this method can directly use solar energy as natural energy without energy exchange. Disadvantage is that small-scale production, long processing time, high cost, by not mechanizing all process. In this method, partial process have carried out outdoor, therefore, this method is affected by weather conditions, and production is unstable. This method require many man power and large lot area. We consider that introduction of technology of freezing into process of salt production. That is freeze concentration. Repeatedly freeze concentration reaches high concentration of seawater. In this study, process of concentration of seawater is focused on production of salt. Experiments on freeze concentration of seawater carried out in the both case of pool freezing and forced convection freezing. The aim of study is to discuss on efficient method of concentration of seawater using freezing.
Salt production
Freeze concentration
Seawater
Pool freezing
Forced convection freezing