PURIFYING METHOD OF ELECTROLYTIC BRINE

• Main Authors: OKI TOSHIAKI, NAGAI KIYOUJI, TERADA KENJI, HATSUTORI MUNEHARU
• Format: Patent
• Language: English
• Published: 11.03.1983
• Subjects: APPARATUS THEREFOR; CHEMISTRY; COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM,RUBIDIUM, CAESIUM, OR FRANCIUM; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTIONOF COMPOUNDS OR NON-METALS; INORGANIC CHEMISTRY; METALLURGY

PURPOSE:To purify a brine for an electrolytic cell of an alkali chloride by the ion exchange membrane method and improve the electrolytic efficiency of the electrolytic cell, by adding a caustic alkali to a brine containing phosphoric acid ions, precipitating impurities with a specific amount of phosphoric acid, and removing the precipitated impurities. CONSTITUTION:A return eletrolyte, containing 10-200mg/l phosporic acid ions, and returned from a brine eletrolytic cell 1 by the ion exhange membrane method is dechlorinated in a dechlorinating tank 2, and a raw salt is added to and dissolved in the dechlorinated electrolyte in a dissolving tank 3. The resultant solution is then introduced into the first reaction chamber 5 and adjusted to >=10pH with an aqueous solution of NaOH 7 to precipitate and remove the contained polyvalent metallic ions. The resultant electrolyte is then introduced into the second reaction chamber 10, and the contained Ca ions are reacted with phosphoric acid 11 in a necessary amount or more to precipitate and remove all the Ca. The formed slurry precipitate is then removed in a continuous precipitating tank 13. The resultant electrolyte is then introduced into a filtering tank 14 to give a clean brine, which is filtered, passed through the second purifying step 15 and fed to the anodic chamber of the electrolytic cell 1.