| 摘要 |
An aqueous solution of sodium hydroxide containing soluble impurities such as a concentrated catholyte produced by a diaphragm electrolysis is cooled by a coolant or a heat-exchanger to form a slurry containing sodium hydroxide hydrate crystals and fine impurity crystals. The fine impurity crystals are adsorbed on bubbles which are formed by vaporizing a dissolved coolant or introducing a gas in the slurry and separated from the slurry. |
