| 摘要 |
The invention comprises a process for regenerating and detoxifying electrolytes which contain sodium nitrate for use in electrochemical treatment of metallic workpieces. The reaction products, like ammonia, formed in the treatment which interfere with the operating process and in some instances are toxic shall be removed as harmless substances. The process according to the invention is characterized by (a) adjusting the electrolyte to a pH value within the range from 4 to 5 and oxidizing the nitrite with hydrogen peroxide to the nitrate or reducing the nitrite with urea to nitrogen. (b) raising the pH value to 11 to 12, precipitating the metal hydroxides and stripping the ammonia by passing air into the electrolyte, (c) precipitating the heavy metal hydrolisates by sedimentation, filtration and/or centrifugation, (d) neutralizing the electrolyte to a pH of 8 to 8.5.
|
