Electrolytic manner null of mirabilite

摘要

PURPOSE: To stably and efficiently electrolyze an aq. concd. sodium sulfate soln. of stabilized composition obtained from soda ash and/or sodium bicarbonate and aq. sulfuric acid without clogging the electrolytic cell and pipeline due to solid deposit, scaling, etc., without any trouble in the cell in the electrolysis using a gas diffusion electrode, without the cell being damaged by the generation of gaseous CO₂ in the cell and with the electrolytic voltage hardly increased. ;CONSTITUTION: An aq. sodium sulfate soln. is electrolyzed by the ion-exchange membrane process to produce sodium hydroxide. In this case, solid soda ash and/or sodium bicarbonate are brought into contact with aq. sulfuric acid at ≥30°C to obtain an aq. sodium sulfate soln. at ≥pH7. Sulfuric acid is added to the soln. to decrease the pH to ≤6, and the soln. is electrolyzed at ≥50°C. The soln. contains ≥20wt.% sodium sulfate, and a gaseous hydrogen diffusion electrode is preferably used as the anode.;COPYRIGHT: (C)1994,JPO&Japio