Abstract
Salt blocking during storage is an important problem to solve. As the physical property of salt crystal seems to be one of its factors to be discussed, we tried to do series of tests for improvement of salt quality from that point of view. Comparison was made as to crystal from in photos, breakage strength, crystal growth rate and crystal nucleation rate given by Toyokura's theory, keeping the liquid level of vacuum evaporator lowest, or in contrast with it a little higher than standard level. Furthermore, we tried seeds feeding for the purpose of crystal size control. In the case of high level operation, agglomeration of crystals seems to be suppressed, while the effect of crystal seeds addition is obscure.
