电积分离铜-分光光度法测定铜浸出液中活性硅

Determination of active silicon in copper leaching solution by spectrophotometry after copper separation via electrodeposition

铜浸出液中含有大量的铜离子,用硅钼蓝分光光度法测定活性硅时,铜离子的蓝色可严重干扰硅的测定。为了消除铜离子对硅测定的干扰,实验对铜浸出液进行了电积分离铜预处理,并主要考察了电流密度对分离铜的效果、硅钼蓝分光光度法不同波长下的吸光度情况、样品中和后盐酸加入量、电积分离铜后试液中各共存元素等因素对硅测定的影响。结果表明:电积分离铜最佳电流密度为5.0A/dm2;硅钼蓝分光光度法测定活性硅时,最佳测定波长为640nm;样品中和后盐酸(1+9)最佳加入量为6.00mL;分离铜后试液中各共存元素对硅测定无明显干扰。当硅质量浓度在0.05~3.00μg/mL时,硅质量浓度与吸光度符合比尔定律,校准曲线相关系数为0.999 9,方法检出限为0.024μg/mL。取不同铜浸出液样品进行精密度考察,硅测定结果的相对标准偏差(RSD,n=12)在0.28%~0.50%之间。将实验方法应用于2个铜浸出液中硅的测定,测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致。

The copper leaching solution contained a lot of copper ions.The determination of active silicon by silicon molybdenum blue spectrophotometry was severely interfered by the blue color of copper ion.In order to eliminate the interference of copper ion with the determination of silicon,the copper leaching solution was pretreated in experiments by copper separation via electrodeposition.The effect of current density on copper separation was investigated.Moreover,the influence of absorbance in silicon molybdenum blue spectrophotometry at different wavelengths,the addition amount of hydrochloric acid after neutralization of sample and the coexisting elements in sample after copper separation via electrodeposition on the determination of silicon was also studied.The results showed that the optimal current density for copper separation via electrodeposition was 5.0 A/dm2.During the determination of active silicon by silicon molybdenum blue spectrophotometry,the optimum measuring wavelength was 640 nm.The optimum addition amount of hydrochloric acid(1+9)after neutralization of sample was 6.00 mL.The coexisting elements in sample after copper separation via electrodeposition had no obvious interference with the determination of silicon.The Beer′s law was obeyed between absorbance and mass concentration of silicon in range of 0.05-3.00μg/mL.The correlation coefficient of calibration curve was 0.999 9,and the detection limit was0.024μg/mL.The precision tests were conducted using different copper leaching solution samples.The relative standard deviations(RSD,n=12)were between 0.28% and 0.50%.The experimental method was applicable for the determination of silicon in two copper leaching solution samples.The found results were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES).