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1. 发明授权

US06475338B1 Method of minimizing transition metal ions during chemical pulping in a digester by adding chelating agent to the digester 失效
标题翻译：在蒸煮器中通过向蒸煮器中加入螯合剂在化学制浆过程中使过渡金属离子最小化的方法
公开(公告)号：US06475338B1
公开(公告)日：2002-11-05
申请号：US08659682
申请日：1996-06-05
申请人： Jian Er Jiang , Kaj O. Henricson
发明人： Jian Er Jiang , Kaj O. Henricson
IPC分类号： D21C102
CPC分类号： D21C3/22
摘要： The production of chemical (e.g., kraft) cellulose pulp much more suited to totally chlorine free or elemental chlorine free bleaching is produced by reducing the bleaching chemical consumability of the produced pulp. The effective alkalinity of the pulp during at least the majority of the cooking stage is maintained at about 15 g/l or above (e.g., about 18-25 g/l), expressed as sodium hydroxide, so as to reduce the charged acid groups (including hexeneuronic acids) by at least 30% (e.g., at least about 50%) compared with pulp cooked at conventional alkalinity. Instead—or in addition to—the cellulosic material which produces the pulp may be heated to a temperature (at least about 100° C., preferably at least about 130° C.) to release significant quantities of the transition metals within it, and preferably while it has this elevated temperature and a dissolved organic solids concentration of about 120 g/l or less, a chelating agent (such as EDTA) is added to combine with a significant quantity of the released transition metals to produce complexes. At least a majority of the complexes are preferably removed (e.g., using an extraction screen in a digester) before the pulp is bleached.
摘要翻译：通过减少所产生的纸浆的漂白化学品消耗能力，生产更适合于完全无氯或无元素无氯漂白的化学（例如牛皮纸）纤维素纸浆。在烹饪阶段的至少大部分期间纸浆的有效碱度保持在约15g / l或更高（例如约18-25g / l），以氢氧化钠表示，以便减少带电的酸基团（包括己烯醛酸）与常规碱度煮熟的纸浆相比至少30％（例如至少约50％）。或者除了生产纸浆的纤维素材料之外，还可以加热到至少约100℃，优选至少约130℃的温度以释放大量的过渡金属，以及优选当其具有这种升高的温度和约120g / l或更低的溶解有机固体浓度时，加入螯合剂（例如EDTA）以与大量释放的过渡金属组合以产生络合物。在纸浆漂白之前，至少大部分复合物优选被除去（例如，在蒸煮器中使用提取筛网）。

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