分光光度法测定钨矿石中钨量不确定度评定

Evaluation of Uncertainty in the Determination of Tungsten Content in Tungsten Ore by Spectrophotometry

根据GB/T14352.1—2010《钨矿石、钼矿石化学分析方法第1部分:钨量测定》以及不确定度评定与表示规范和要求,对分光光度法测量钨矿石中钨量进行测量不确定度分析与评定,为准确测量钨矿石中钨的含量、测量结果评价以及测量误差来源提供参考依据。系统分析了测量过程中由重复性、样品称量、定容、样品稀释、标准溶液、校准曲线拟合和转换系数7个不确定度分量,并对每个不确定度分量进行了计算,确定了各不确定分量的大小。最终计算了合成相对标准不确定度以及扩展不确定度。结果表明,钨矿石中钨含量为(0.450±0.030)%(k=2),钨矿石钨含量测量过程中,重复性是不确定度的主要来源,标准溶液及曲线拟合对不确定度也有较大贡献,因此,在测量过程需要重点关注这些因素。可以采取增加测量次数,选用合适的移液管进行标准溶液稀释以及采用合适浓度范围的校准曲线等措施以提高检测准确度。

Based on the GB/T14352.1—2010“Methods for Petrochemical Analysis of Tungsten and Molybdenum Ores-Part 1:Determination of Tungsten Content”and the specifications and requirements for uncertainty evaluation and representation,uncertainty in the determination of tungsten content in tungsten ore using spectrophotometry was analyzed and evaluated.This provides reference basis for accurate measurement of tungsten content in tungsten ore,evaluation of measurement results,and sources of measurement errors.A systematic analysis was conducted on seven uncertainty components during the measurement process,including repeatability,sample weighing,constant volume,sample separation,standard solution,standard curve fitting,and conversion coefficient.Each uncertainty component was calculated and the contribution of each uncertainty component was identified.Finally,the combined relative standard uncertainty and expanded uncertainty were calculated.The results show that the tungsten content in tungsten ore is(0.450±0.030)%(k=2).In the measurement process of tungsten content in tungsten ore,repeatability is the main source of uncertainty,and standard solutions and curve fitting also make a significant contribution to the uncertainty.Therefore,it is necessary to focus on these factors during the measurement process.Measures such as increasing the number of measurements,selecting appropriate pipettes for standard solution dilution,and using calibration curves with appropriate concentration ranges can be taken to improve the quality of detection.