| 摘要 |
PURPOSE:To stabilize current efficiency by feeding an aqueous soln. of salt to the anode chamber of an electrolytic cell divided with an ion exchange membrane after removing iodine compounds to eliminate unfavorable influence on electrolysis. CONSTITUTION:Rock salt contg. iodine compounds is fed to a salt dissolving vessel 12 and dissolved to prepare a satd. aqueous soln. of salt. The soln. is passed through a reaction vessel 14, a filter 19 and a column 20 packed with a chelate resin to remove dissolved ions of Ca, Mg and Fe to <=about 0.1ppm. The pH of the resulting soln. is adjusted to <=about 2 by adding sodium hypochlorite 21 and hydrochloric acid 22, and the soln. is passed through a column 23 packed with an anion exchange resin to remove iodine and iodine ions to <=10ppm. The purified nearly-satd. aqueous soln. of NaCl is supplied to an anolyte tank 7, and it is fed to the anode chamber 6 of an electrolytic cell 1. By feeding the purified soln., a reduction of current efficiency and an increase of voltage can be avoided, and stable electrolysis can be carried out.
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