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1.背景在硬质镀铬,装饰镀铬,防蚀镀铬,ABS树脂的蚀刻以及白铁,铝等的铬酸处理等工序中,通常使用数拾至数百克/升的浓铬酸,该铬酸随着Fe,Zn等金属浓度增大,Cr~(6+)被还原,Cr~(3+)增大而作为老化废酸被废弃。由于在本工序被处理的产品要在下一工序进行水洗;故产生含数百至数千ppm的低浓度铬酸排水。含在浓老化废酸和稀洗涤排水中的Cr~(6+)具有剧毒,故在排放到公用水域之前要把排
1. Background In hard chrome plating, decorative chrome plating, anticorrosive chrome plating, ABS resin etching, and chromic acid treatment of white iron, aluminum, etc., chromic acid pick-up to hundreds of grams / liter is usually used. As the concentration of Fe, Zn and other metals increases, Cr 6+ is reduced and Cr 3+ is increased to be discarded as aged spent acid. Since the products processed in this process are to be washed in the next process, a low concentration of chromic acid drainage containing hundreds to thousands of ppm is produced. Containing Cr_ (6+) in concentrated and aged waste acid and dilute scrubbing and draining water is highly toxic, so before discharging to public water,