Recrystallization characteristics of solar salt after removing of bittern and impurities.

摘要

Recrystallization characteristics of salt after removal of bittern and impurities from solar salt (SD) were investigated. To remove the bittern the SD was treated at 30, 40 and 50 degrees C at 95% humidity. 86% of the bittern was removed when the SD was kept at 30 degrees C for 3 wk. Total of impurities in SD was 6.94% (w/w) with organic impurity 5.58% and inorganic impurity 1.36%. Most organic impurities (89%) were soluble. When the SD was roasted at 350 degrees C for 40 min, 90.14% of the soluble organic impurities were removed, however, reduction of impurities was greater when the SD was roasted for 50 min at 350 degrees C. L* value decreased while a* and b* values increased when the SD was roasted for 40 min at 350 degrees C. L* value increased while a* and b* values decreased with SD roasted >50 min at 350 degrees C. The size of recrystallized pure salt was positively correlated to temp. and depth of salt solution, while the crystallization time was negatively correlated to temp. and salinity. Yield of recrystallized salt was negatively correlated to temp. Overall acceptability tended to increase at low crystallization temp. and high salinity.