Na2EDTA反滴定法测定铜镍合金中的镍

采用Na2EDTA返滴定法测定铜镍合金中的镍含量， 用柠檬酸钠、硫代硫酸钠和酒石酸做掩蔽剂，丁二酮肟沉淀分离，以二甲酚橙为指示剂，加入过量的Na2EDTA,用氯化锌标准溶液返滴定。方法能很好地分离铜及其他杂质的干扰。试验方法用于测定铜镍合金中的镍含量，测定结果的相对标准偏差（RSD，n=9）为0.0456%～0.2409%,加标回收率为99.30%～101.10%如有残渣，过滤之后将残渣消解，用光谱测定不溶渣中的镍含量。能够满足日常样品的检测要求。

Determination of nickel in crude copper by Na2EDTA titration

Abstract: The content of nickel in crude copper was determined by Na2EDTA back titration. Sodium citrate, sodium thiosulfate and tartaric acid were used as hiding agents. Dimethylglyoxime was precipitated and separated .Xylenol orange was used as indicator and excessive Na2EDTA was added to back titration with zinc chloride standard solution .The interference of copper and other impurities can be separated by this method .The relative standard deviation(RSD, n=9) of the test results is 0.0456%-0.2409% and the recovery rate 99.73%-100.30% . If there is residue, the residue will be digested after filtrating, and the content of nickel in the insoluble residue will be determined by spectrum .It can meet the test requirement of daily samples.