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OwnerVeniamin Petrovich Zaplatin, Vasily Petrovich Svitelsky +6inventors
InventorsVeniamin Petrovich Zaplatin, Vasily Petrovich Svitelsky, Lev Ivanovich Galov, Alla Konstantinovna Djukareva, Rozalia Grigorievna Sklyar, Vasily Alexeevich Denisovich, Dmitry Alexeevich Shirokov, Vladimir Alexandrovich Shevchenko
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A cellulose containing vegetable material is bleached by the steps of chlorinating said material, followed by ammonia treatment and post bleaching with washing stages between said steps. Waste waters resulting from the washing stages are purified by subjecting said waste waters to electrodialysis and recovering ammonium chloride from the purified waste waters. The recovered ammonium chloride is used to pre-treat the cellulose material prior to chlorination thereof and the purified waste waters are reused in the washing stages.
In a process for bleaching a cellulose-containing vegetable material which comprises the steps of chlorinating cellulosic material in a chlorination zone followed by ammonia treatment and post bleaching with washing stages between said steps, the improvement which comprises purifying waste waters resulting from said washing stages by subjecting said waste waters to electrodialysis and recovering ammonium chloride from the purified waste waters, treating said cellulosic material with said ammonium chloride prior to the chlorination step and re-using the purified waste waters in the wash stages thereby providing a closed cycle system and eliminating the drainage of polluted wash waters to natural water sources.
Dependencies are inferred from the claim text.