| 摘要 |
PURPOSE:To obtain a bleaching bath with low toxicity and superior bleaching power to developed silver by using 1-hydroxyethylidene-1,1-diphosphoric acid or its salt and trivalent Fe ion as principal components. CONSTITUTION:A photographic bleaching bath is prepared contg. 1-hydroxyethylidene-1,1-diphosphoric acid represented by the formula or its salt and trivalent Fe ion as principal components at 0.1-1.0mol concn. each. This chelating agent has low toxicity, and the used bleaching bath is treated with aluminum sulfate or lime to form an insoluble precipitate which can be filtered out easily, resulting in no environmental pollution. |
