熔融制样-X射线荧光光谱法测定铁矿石中全氯  

Determination of total chlorine in iron ore by X-ray fluorescence spectrometry with fusion sample preparation

作　　者：冯丽丽 管嵩 范玉 丁仕兵 吴雅俊 邹雯雯 FENG Lili;GUAN Song;FAN Yu;DING Shibing;WU Yajun;ZOU Wenwen(Technology Center of Qingdao Customs,Qingdao 266500,China;Qingdao Bozheng Inspection Technology Co.,Ltd.,Qingdao 266500,China)

机构地区：[1]青岛海关技术中心,山东青岛266500 [2]青岛博正检验技术有限公司,山东青岛266500

出　　处：《冶金分析》2023年第12期53-59,共7页Metallurgical Analysis

基　　金：海关总署科研计划项目(2020HK250)。

摘　　要：全氯含量是铁矿石质量评价的重要指标之一,建立铁矿石中全氯含量的测定方法具有重要意义。X射线荧光光谱仪测定铁矿中全氯含量面临的难点在于氯易被污染,在高温下有损失,以及缺乏足够浓度跨度的含氯标准样品。将样品于105 ℃预干燥后用混合熔剂(四硼酸锂和偏硼酸锂以质量比为12∶22混合配制)直接熔融,避免了可能带来的氯污染和预灼烧氧化过程中导致的氯损失,用氯化钠基准试剂和氧化铁高纯试剂混合配制具有一定浓度梯度的校准样品系列绘制校准曲线,以理论α系数法校正元素间的基体效应,实现了熔融制样-波长色散X射线荧光光谱法对铁矿石中全氯含量的测定。方法校准曲线的线性相关系数为0.999 6,方法检出限为0.003 2%(质量分数,下同),检测范围为0.016%~1.2%。选取4个铁矿石样品,按照实验方法分别平行制备11个样片并进行测定,测定结果的相对标准偏差(RSD,n=11)为0.28%~3.9%。按实验方法对7个铁矿石标准样品和4个由氯化钠基准试剂和氧化铁高纯试剂混合配制得到的铁矿石合成样品进行测定。结果表明,有10个样品的测定平均值(AVE)在标准值/参考值(Ac)的扩展不确定度范围内;另外1个标准样品的AVE与Ac差值稍大于扩展不确定度,但∣AVE-Ac∣≤C,表明测定结果和标准值之间无显著性统计差异;进一步的t检验结果表明,这11个样品的AVE与Ac无显著性差异。The total chlorine content is one of the important indicators for evaluating the quality of iron ore,so it is important to establish a method for determination of total chlorine content in iron ores.The difficulty for determination of total chlorine in iron ore by X-ray fluorescence spectrometry(XRF)lies in the fact that chlorine is easily polluted,lost at high temperature,and lack of certified reference materials containing chlorine with sufficient concentration span.The sample was pre-dried at 105℃and then directly fused with the mixed flux(lithium tetraborate and lithium metaborate were mixed at mass ratio of 12∶22),avoiding the possible contamination of chlorine and loss of chlorine in pre-ignition oxidation process.The calibration sample series with certain concentration gradients were prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent to draw the calibration curve.The matrix effects among elements were corrected by the theoreticalαcoefficient method.The determination of total chlorine in iron ore was realized by wavelength dispersion-XRF with fusion sample preparation.The linear correlation coefficient of calibration curves was 0.9996.The detection limit was 0.0032%(mass fraction,the same below),and the detection range was 0.016%-1.2%.Four iron ore samples were selected,and 11 sample sheets were prepared and determined in parallel according to the proposed method,respectively.The relative standard deviations(RSD,n=11)of determination results were between 0.28%and 3.9%.7 certified reference materials and 4 synthetic samples of iron ore prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent were determined according to the proposed method.The results showed that the average found(AVE)of 10 samples was within the expanded uncertainty scope of standard value/reference value(Ac).The difference of AVE and Ac for the other certified reference material was slightly higher than the expanded uncertainty,but∣AVE-Ac∣≤C,indicating that th

关 键 词：熔融制样 X射线荧光光谱法(XRF) 全氯 铁矿石 四硼酸锂 偏硼酸锂 

分 类 号：O657.34[理学—分析化学] TF031[理学—化学]