PURPOSE: To feed chlorine stably, to recover excess chlorine effectively, and to prepare bromine in high yield, by regulating an amount of feed of chlorine in such a way that coloring degree of a washing solution of an exhaust gas to be used as a raw material is made constant.
CONSTITUTION: In a method wherein an aqueous solution containing bromine ion is treated with chlorine, and liberated bromine is distilled and recovered, a distilled vapor from the top of the reaction distillation column 1 is condensed 2 and separated into an uncondensed exhaust gas and a condensed solution containing condensed bromine, part of the aqueous solution containing bromine ion of raw material is brought into contact with the uncondensed exhaust gas in the exhaust gas cleaning column 4, unreacted chlorine in the exhaust gas is reacted with bromine ion, fed to the reaction distillation column 1, and an amount of feed of chlorine to the column 1 is regulated in such a way that coloring degree caused by liberated bromine in the solution is made constant. While, the residue of the solution B of raw material is brought into contact with the condensed solution in the dechlorinating column 3, chlorine dissolved in condensed bromine is reacted with bromine ion, removed, the bromine solution is separated and sent to the storage tank 6. The aqueous solution containing bromine ion after the contact treatment is sent to the reaction distillation column 1. Bromine is continuously prepared by the above-mentioned method.
FUNAKI AKIRA
IWATA ATSUKAZU
FURUYA RIYOUICHI
