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采用盐酸、硝酸、氢氟酸和高氯酸加盖溶解样品,选择分析线和内标线分别为Cd 226.502 nm和Y 371.029 nm,使用电感耦合等离子体原子发射光谱(ICP-AES)-内标法测定镉,从而建立了铜精矿中镉的测定方法.通过改变四酸的加入量以及加盖状况进行试验,结果表明,对于常见样品,采用10.0 mL盐酸、10.0 mL硝酸、3.0 mL氢氟酸溶解和3.0 mL高氯酸加盖溶解并赶氟冒烟,再补加2.0 mL高氯酸至白烟冒尽可以使样品溶解完全,对于个别样品,需重复加高氯酸冒烟,直至样品完全溶解.比较了用内标法和基体匹配法在消除基体干扰和仪器及环境波动方面的效果,在相同条件下,内标法测定镉的精密度与基体匹配法基本一致,相对标准偏差(RSD,n=11)为0.9%~1.1%;另外,进行了铜精矿中共存元素的干扰试验,发现随着铜和铁基体加入量的增加,镉的测定值呈逐渐下降的趋势,而通过内标法测定可以消除这种影响.镉的质量浓度在0.025~10.0 μg/mL之间与其对应的发射强度呈线性,线性相关系数r=0.999 8.方法检出限为0.000 2%(质量分数),方法中镉的测定范围在0.001 1%~2.0%(质量分数)之间.按照实验方法测定VS2891-84铜精矿标准物质中铜,结果与认定值相符,其相对误差(RE)为0.34%.

The sample was dissolved with hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid under covering conditions, and the analytical line and internal standard line was Cd 226.502 nm and Y 371.029 nm, respectively.Thus, a determination method of cadmium in copper concentrate was established by inductively coupled plasma atomic emission spectrometry(ICP-AES) combined with internal standard method.The effect of acid dosages and covering conditions was investigated.The results indicated that when 10.0 mL of hydrochloric acid, 10.0 mL of nitric acid, 3.0 mL of hydrofluoric acid and 3.0 mL of perchloric acid was added to dissolve sample with covering and smoking for removing fluorine, and 2.0 mL of perchloric acid was added successively until smoke was disappear, the common sample could be dissolved completely.For specific samples, the addition of perchloric acid and smoking were repeated until the samples were completely dissolved.The effect of internal standard method and matrix matching method on elimination of matrix interference, instrument and environment fluctuation was compared.The determination precision of cadmium by internal standard method was basically consistent with that of matrix matching method under the same conditions.The relative standard deviations (RSD, n=11) were between 0.9% and 1.1%.Moreover, the interference tests of coexisting elements in copper concentrate were conducted.It was found that the determination results of cadmium gradually decreased with the addition of copper and iron matrix.This influence could be eliminated by internal standard method.The mass concentration of cadmium in range of 0.025-10.0 μg/mL showed linearity to its corresponding emission intensity with correlation coefficient of r=0.999 8.The detection limit of method was 0.000 2% (mass fraction).The determination range of cadmium was 0.001 1% and 2.0% (mass fraction).The content of cadmium in certified reference material of copper concentrate (VS2891-84) was determined according to the experimental method.The results were consistent with the certified values.The relative error (RE) was 0.34%.