EDTA滴定法测定复杂铜阳极泥中铋

铜阳极泥成分受电解工艺参数、阳极板质量、现场控制等多种因素的影响,元素种类和含量复杂多变。采用EDTA滴定法检测含高铅、高钡的复杂铜阳极泥中铋时,样品溶解过程常出现不溶结块,从而易对铋形成包裹,导致测定结果误差大、稳定性差。实验采用王水-硫酸溶解样品,在硝酸介质中用EDTA滴定法检测铋含量。通过试验确定称样量为0.2~1.0g并满足溶液中铋质量浓度不小于140mg/L,以硝酸-酒石酸混合酸作为浸取酸,调节溶液pH值至1.5~1.7,用1.060×10^-2 mol/L EDTA标准溶液测定铋,终点敏锐。按照实验方法测定铜阳极泥实际样品中铋,测定结果的相对标准偏差(RSD,n=9)为0.86%~1.5%,回收率为98%~101%。方法有效解决了复杂铜阳极泥中的铋量不易准确测定的问题,适用于铋含量为1%~12%(质量分数)的复杂铜阳极泥样品的检测。

Determination of bismuth in complex copper anode slime by EDTA titration

The composition of copper anode slime is affected by various factors such as the parameters of the electrolysis process, the quality of the anode plate, and field control. The type and content of elements are complex and variable. During the determination of bismuth in complex copper anode slime samples with high content of lead and barium by EDTA titration method, the insoluble agglomerates usually occurs in sample dissolution process, which will easily cause covering of bismuth, leading to large errors and poor stability of the measurement results. The sample was dissolved with aqua regia and sulfuric acid. The content of bismuth was determined by EDTA titration method in nitric acid medium. The results showed that the determination end-point was sharp under the following experimental conditions: the sample weight was 0.2-1.0g, and the mass concentration of bismuth in solution was higher than 140mg/L; nitric acid and tartaric acid mixture were used as leaching acid; the pH value of solution was adjusted to 1.5-1.7; the content of bismuth was determined using 1.060×10^-2 mol/L EDTA standard titration solution. The content of bismuth in actual copper anode slime sample was determined according to the experimental method. The relative standard deviations (RSD, n=9) of the measurement results were between 0.86% and 1.5%, and the recoveries were between 98% and 101%. The proposed method effectively solved the problem that the content of bismuth in complex copper anode slime was difficult to be accurately measured. It was suitable for the analysis of complex copper anode slime samples with bismuth content in range of 1%-12% (mass fraction).