| 摘要 |
PURPOSE:To enable deterioration condition of ion exchange membranes to be effectively judged by extracting part of anode chamber solution through discharge ports, measuring its pH then supplying hydrochloric acid to each electrolytic cell based on this pH thereby specifying the pH at the time of electrolyzing alkali halide by using ion exchange membranes. CONSTITUTION:A pH measuring machine 91-4 is provided between the discharge header 61-4 of each electrolytic cell C1-4 and discharge main pipe 2 to measure the pH of the anode chamber discharge solution of each cell. A suitable amount of hydrochloric acid is supplied through branch pipes 111-4 from hydrochloric acid piping 10 so that the pH measured value may be maintained at 4 or less, preferably 1-3. The openings of the valves 121-4 at the respective branch pipes 111-4 are automatically controlled by the signals from the pH measuring machines 91-4. With this method, exchanging of the membranes, their mending and other treatments are accomplished at the time when, e.g., initial current efficiency or initial hydrochloric acid addition rate becomes 10% or twice or the like. |
