活性炭吸附-碘量法测定金矿石中金的不确定度评定

Uncertainty Evaluation for Iodometric Determination of Gold in Gold Ores with Activated Carbon Adsorption

根据测量不确定度的评定方法,对活性炭吸附-碘量法测定金矿石中的金进行不确定度评定。实验样品从低温升至650℃灼烧2 h除硫,用50%(体积分数)的王水溶解1 h,经活性炭动态吸附抽滤,将载金炭灰化复溶,用硫代硫酸钠标准溶液滴定,该方法简便、快速、实用性强。测量结果的不确定度由滴定样品消耗的硫代硫酸钠标准工作溶液体积、硫代硫酸钠对金的滴定度、称量质量、重复测定等不确定度分量组成。对各个不确定度分量进行分析并量化,合成得到测量结果的标准不确定度,换算成扩展不确定度。通过评定不确定度主要是由硫代硫酸钠对金的滴定度引入。

According to the evaluation method to measure uncertainty,we evaluated the uncertainty of the gold determination in ore by using activated carbon adsorption-iodimertric.The experimental samples were calcined from room temperature to 650℃ for 2 h to remove sulphur,then dissolved by the 50%（volume fraction） aqua regia for 1 h.The gold was absorbed from the solution by activated carbon dynamic adsorption suction filter.The carried gold carbon cineration was dissolved again before the gold was titrated by sodium hyposulfite standard solution.This method is simple,rapid and strong practicability.The uncertainties of measurement consist of the consumed volumes and titer of sodium hyposulfite standard solution to gold,sample weight,duplications and so on.The standard uncertainty was obtained by quantifing and synthesizing each branch of uncertainties measurement results,then converted into the expansion uncertainty.The result indicates that the main uncertainty is from the titer of sodium hyposulfite standard solution.