碱熔-电感耦合等离子体原子发射光谱法测定铁矿石中铬铌钼钨锡

准确快速测定铁矿石中微量元素,对提高钢及钒产品质量具有十分重要的意义,但针对铬、铌、钼、钨、锡等难以被酸溶解的元素,选择适宜的样品前处理方法并采用电感耦合等离子体原子发射光谱法(ICP-AES)测定,有利于提高准确度和测试效率。试验采用碳酸锂-硼酸混合熔剂高温熔融样品,再经盐酸浸取、酸化;选择Cr 267.716nm、Nb 269.706nm、Mo 202.030nm、W 224.875nm、Sn 189.989nm为分析谱线,基体匹配法绘制校准曲线消除基体效应的影响,采用电感耦合等离子体原子发射光谱法测定铁矿石中铬、铌、钼、钨、锡。各待测元素校准曲线的线性相关系数均不小于0.9996;方法检出限为0.002%~0.003%。方法应用于铁矿石实际样品中铬、铌、钼、钨、锡的测定, 结果的相对标准偏差(RSD,n=9)为1.0%~3.8%;回收率为94%~105%。按照实验方法测定4个铁矿石样品中铬、铌、钼、钨、锡,结果与其他化学分析方法(其中铬、铌、锡采用光度法,钨、钼采用电感耦合等离子体质谱法)测定值一致。

Determination of chromium,niobium, molybdenum,tungsten, tin in iron ore by inductively coupled plasma atomic emission spectrometry with alkali fusion

The accurate and rapid determination of microelements in iron ore had very important significance for the quality improvement of steel and vanadium products. For the elements which were hardly dissolved with acid including chromium, niobium, molybdenum, tungsten and tin, the selection of proper sample pretreatment method and the determination method of inductively coupled plasma atomic emission spectrometry (ICP-AES) were helpful to improve the accuracy and efficiency for determination. The sample was melted at high temperature with lithium carbonate-boric acid mixed flux followed by leaching and acidification with hydrochloric acid. Cr 267.716nm, Nb 269.706nm, Mo 202.030nm, W 224.875nm and Sn 189.989nm were selected as the analytical lines. The calibration curves were prepared by matrix matching method to eliminate the influence of matrix effect. The contents of chromium, niobium, molybdenum, tungsten and tin in iron ore were determined by ICP-AES. The linear correlation coefficients of calibration curves of elements were all not less than 0.9996. The detection limits of method were in range of 0.002%-0.003%. The proposed method was applied for the determination of chromium, niobium, molybdenum, tungsten and tin in actual sample of iron ore. The relative standard deviations (RSD, n=9) of results were between 1.0% and 3.8%, and the recoveries were between 94% and 105%. The contents of chromium, niobium, molybdenum, tungsten and tin in four iron ore samples were determined according to the experimental method. There results were consistent with those obtained by other chemical analysis methods (spectrometric determination for chromium, niobium and tin, and inductively coupled plasma mass spectrometric determination for tungsten and molybdenum).