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铜合金中以杂质存在的镍一般不超过0.1%,应用丁二酮肟比色法测定镍时,须把铜分离后再显色。我们采用在微酸性溶液中加入亚硫酸来还原铜离子,用硫氰化铵与亚铜反应生成硫氰化亚铜沉淀,过滤分离。分析方法: 称取试样(含镍0.01～0.10%称0.5克;0.1～0.5%称0.25克;0.5～1.0%称0.1克)于100毫升量瓶中,加入5毫升浓盐酸,分次加入30%过氧化氢2毫升,微热溶解完全后煮沸至无小气泡产生,稍冷,用1:1氨水中和至刚有沉淀产生,再以1:1
Copper alloy impurities in the presence of nickel is generally not more than 0.1%, the use of dimethylglyoxime colorimetric determination of nickel, the copper should be separated after the color. We use a slightly acidic solution by adding sulfurous acid to reduce copper ions, with ammonium thiocyanate and cuprous thiocyanate reaction of copper precipitation, filtration and separation. Analysis: Weigh the sample (containing 0.5-0.01% nickel 0.5 g; 0.1-0.5%, said 0.25 g; 0.5-1.0%, said 0.1 g) in 100 ml volumetric flask, add 5 ml of concentrated hydrochloric acid was added in portions 30% hydrogen peroxide 2 ml, after the completion of the micro-thermal boiling boiled until no small bubbles, slightly cold, with 1: 1 ammonia and to just precipitate, and then 1: 1