PRODUCTION OF CAUSING SODA WHICH DOES NOT CONTAIN POTASSIUM

摘要

PURPOSE:To directly and efficiently produce NaOH without contg. K at a high yield by subjecting brine from which Mg2+ and Ca2+ are removed to adsorptive removal of K+ by cryptomelane type hydrous manganese oxide, then to a salt electrolysis. CONSTITUTION:NaOH and Na2CO3 are incorporated in an addition tank 4 to the brine contg. about 300g/l NaCl obtd. by dissolving a raw material salt in a dissolution tank 1 to allow the Mg2+ and Ca2+ contained therein to precipitate as Mg(OH)2 and CaCO3 and thereafter, the brine is passed through a sand filter tank 6. The brine is thereafter passed through a chelate resin column 8 where the Mg2+ and Ca2+ are completely removed from the brine. This brine is then passed into a potassium selective adsorbent column 10. The brine is passed through the potassium selective adsorbent consisting of the cryptomelane type hydrous manganese oxide, by which K+ is adsorbed away. The salt electrolysis of the above-mentioned brine is thereafter effected in an electrolytic cell 12 having a cation exchange membrane 15. The NaOH which does not contain the K is directly obtd in this way.