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一、引言一般氯碱厂工业盐水SO_4＂测定大部分采用盐酸联苯胺法和EDTA法,盐酸联苯胺法要经过沉淀和过滤,手续繁琐,测定时间长。EDTA法操作简便,测定时间大大缩短,但当3-4组阳离子和其他阴离子存在时,都难测出精确结果。由设备和原料中会带进Ca~(++)、Mg~(++)、Fe~(+++)、 Ni~(+++)、Cr~(+++)、Mn~(++)等金属离子,用EDTA法测定终点难判断,显色不明显,分析结果偏低,甚至会产生负值。根据上述情况,
I. Introduction Chlorine-alkali plant industrial brine SO_4 "Determination of the majority of the use of benzidine hydrochloride and EDTA method, benzidine hydrochloride method to be precipitated and filtered, tedious procedures, the determination of a long time .EDTA method is simple, the determination of time greatly reduced, but when In the presence of cations and other anions of Group 3-4, it is difficult to detect the exact results, and Ca ~ (++), Mg ~ (++), Fe ~ (+++), Ni ~ (+++), Cr ~ (+++), Mn ~ (+ +) and other metal ions, the determination of the endpoint by EDTA method is difficult to judge, the color is not obvious, the analysis results are low, and even negative. According to the above Happening,