SODIUM-CHLORATE SPLITTING - A NEW SOLUTION TO THE PROBLEMS OF CHEMICAL IMBALANCE IN KRAFT MILLS

Sodium hydroxide and chloric acid can be produced from sodium chlorate through the use of bipolar membrane electrodialysis (BME). The system was operated in both the batch and feed-and-bleed modes, producing so dium hydroxide (0.85 M at 36.1 mL/min) and chloric acid (1.14 M at 12. 6 mL/min). The current density was 137 mA/cm(2) and the effective memb rane area 1000 cm(2). The system required a power input of about 320 W for steady-stare operation. In a subsequent step, the chloric acid ca n be converted into chlorine dioxide without adding sulphuric acid int o the generator. The on-site generation of chlorine dioxide and sodium hydroxide through this approach can help to address two problems faci ng kraft mills today: firstly, it can provide sodium hydroxide without any concomitant chlorine; and, secondly, it can reduce the amount of sulphuric acid used in chlorine dioxide generators, thereby decreasing , or elimininating, the amount of sodium sulphate (or sesquisulphate) formed as by-product.