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银镍材料中镍的络合滴定,JB 4107.5-85中采用丁二肟沉淀分离镍后,在pH6～7的微酸性介质中,用二甲酚操作指示剂,锌盐返滴定.该法需进行沉淀分离.操作条件严格,费时,不能适应于生产控制的要求.本文采用氮川三甲撑膦酸(简称NTMP)掩蔽Ti、Th、Zr、Sn、Fe、In、Tl、Sb、Nb、Ta等高价金属离子和碱土金属离子.氟化氢钾掩蔽锰.在pH5.5的乙酸-乙酸钠缓冲溶液条件下,用2-[(3,5-二氯-2-吡啶)偶氮]-5-二氨基酚(简称3,5-dicl-DEPAP)作指示剂,锌盐返滴定,获得了较为满意的结果.1 主要试剂锌标准溶液:0.01mol·L~(-1),称取0.8138g基准氧化锌于400ml烧杯中,加入HNO_3(1+1)10ml溶解,稀释于1000ml量瓶中.EDTA标准溶液:0.02mol·L~(-1)称取7.4450g基准乙二胺四乙酸二钠于400ml烧杯中,加热溶解,冷却移入1000ml量瓶中,用水稀释至刻度,贮于塑料瓶中.3,5-dicl-DEPAP乙醇溶液:0.25%NTMP溶液:5%KHF_2溶液:10%乙酸-乙酸钠缓冲溶液:pH5.5
Nickel complexation titration of nickel-nickel materials, JB 4107.5-85 in the separation and separation of nickel with butanedioxime, pH 6 ~ 7 in a slightly acidic medium, with xylenol operating indicator, zinc salt back titration. The conditions of operation are strict and time-consuming, and can not be adapted to the requirements of production control.In this paper, Ti, Th, Zr, Sn, Fe, In, Tl, Sb, Nb and Ta are masked with trimethylenephosphonic acid (abbreviated as NTMP) Such as high-valent metal ions and alkaline-earth metal ions, potassium bifluoride to mask manganese, and then treated with 2 - [(3,5-dichloro-2-pyridyl) azo] -5- Diaminophenol (referred to as 3,5-dicl-DEPAP) as an indicator, zinc back titration, obtained more satisfactory results.1 The main reagent zinc standard solution: 0.01mol·L -1, weighed 0.8138g Reference zinc oxide in 400ml beaker, add HNO_3 (1 + 1) 10ml dissolved, diluted in 1000ml volumetric flask.EDTA standard solution: 0.02mol · L -1 (7.4450g), weighed standard ethylenediaminetetraacetic acid disodium In a 400 ml beaker, dissolve with heating, transfer to a 1000 ml volumetric flask, dilute with water to the mark, and store in a plastic bottle.3,5-dicl-DEPAP ethanol solution: 0.25% NTMP solution: 5% KHF_2 solution: 10% Sodium acetate buffer solution : pH5.5