Abstract
The present report describes scale formation in the concentration process of sea water with ion exchange membranes.
Magnesium hydroxide and calcium carbonate (Aragonite) were found on the cation exchange membranes in sea water compartments, and calcium sulfate dihydrate added to them was found on the anion exchange membranes in the concentration compartments.
Types of the scales were divided into five classes according to their shapes and compositions.
Some experiments were conduncted to elucidate the causes of scale formation. On the basis of the data thus obtained, it was confirmed that (1) the components of the scales were entirelly or locally concentrated over their solubilities and (2) the change of the pH caused by the development of concentration polarization were the main causes for the scale formation.
