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铵盐镀锌檀液的分析在pH=10的氨性介质中,用三乙醇胺掩蔽槽液中Fe~(3+)离子,以PAN为指示剂,用EDTA直接滴定锌。槽液中Pb、Cu、Cd等杂质含量少于1mgl~(-1)时,滴定终点不受影响.超过此限,可用少量二乙胺基硫代甲酸钠(简称DDCT)掩蔽之。锌同样产生白色沉淀,加过量的EDTA能使DDTC-Zn白色沉淀完全溶解,再以锌盐回滴过量的EDTA。本法适用于氨三乙酸、氯化铵、氯化锌、硼酸的配方体系及氯化铵、氯化锌、柠檬酸的配方体系两种槽液中锌的无氰分析。测定误差为1gl~(-1)以下(与氰化钾法比较).
Analysis of ammonium salt of zinc dross solution pH = 10 in ammonia medium, with triethanolamine masking Fe ~ (3 +) ions in the bath, with PAN as an indicator, direct titration of zinc with EDTA. When the content of Pb, Cu, Cd and other impurities in the bath is less than 1 mg l -1, the titration end point is not affected, and if it exceeds this limit, it can be masked with a small amount of diethylaminoethyl thiocarbamate (DDCT). Zinc also produces a white precipitate, plus an excess of EDTA can make the DDTC-Zn white precipitate completely dissolved, then the zinc salt back excess EDTA. The method is applicable to the cyanide-free analysis of zinc in two kinds of bath solutions of the compound system of ammonia triacetic acid, ammonium chloride, zinc chloride and boric acid and the formula system of ammonium chloride, zinc chloride and citric acid. The determination error is below 1gl -1 (compare with potassium cyanide method).