Abstract
Copper, zinc, iron and aluminium contents of thirty samples of various evaporating salt (salts manufactured by vacuum evaporator, thermo-compression evaporator, closed pan, open pan and by hot spring heat utilization), were determined, and found that the average contents of copper, zinc, iron and aluminium is 0.17, 0.34, 1.99 and 0.36 milligram respectively per 100 gram of salt, and generally distributed more in the insoluble matter rather than in water soluble parts.
The greater part of these elements in original sea water is distributed in gypsum deposited by concentration.
But a majority of these elements in the salt is derived from the salt making plants, and these are a relation that the high zinc contents in the water soluble part of salt tend also to contain high copper contents in the insoluble matter.
