卡林型金矿金砷成分分析标准物质研制

卡林型金矿因其含砷影响金的分析和选冶回收率而备受关注,需要研制相应的标准物质支撑应用研究。本文依托近年来探明的超大型卡林型金矿——阳山金矿采集候选物,按照国家一级标准物质技术规范研制了4种卡林型金矿标准物质GBW07854~GBW07857。共有20家实验室联合定值,金主要分析方法为原子吸收光谱法和火试金法,湿法分析采用梯度焙烧-活性炭吸附金而分离砷等干扰组分;砷分析主要采用电感耦合等离子体发射光谱法和分光光度法。引用金量分析相对偏差允许限界定组内离群值,弥补了Dixon法和Grubbs法剔除离群值不够完全的缺陷。均匀性检验指标FF0.05(29,30)=1.84,表明组内和组间均无明显差异;在22个月内进行了5次检验,稳定性良好。4种标准物质金和砷的定值结果准确度均优于同量级的国家一级金矿石标准物质和国外含砷多金属矿石标准物质。该系列标准物质可用作卡林型金矿金和砷分析与研究等工作的量值标准。

Preparation of Gold and Arsenic Certified Reference Materials for Chemical Composition Analysis in Carlin-type Gold Deposits

BACKGROUND: Carlin-type gold deposits have attracted much attention because of the influence of As on the analysis and recovery of gold. It is necessary to develop the specific reference materials (RM) to support application research.OBJECTIVE: Study samples were collected from the super large Carlin-type gold deposit in the Yangshan gold mine, discovered in recent years. Four kinds of reference materials GBW07854-GBW07857 for Carlin-type gold ore were developed according to country-level standard technical specification.METHODS: A total of 20 laboratories simultaneously determined element values. The main gold analysis methods included Atomic Absorption Spectrometry and Fire Assay. Wet analysis uses gradient roasting-activated carbon adsorption of gold to separate arsenic and other interference components. Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and Spectrophotometry were mainly used to analyze arsenic. Citation analysis relative deviation permissible limit to define within-group outliers makes up for the incompleteness of the Dixon and Grubbs methods to eliminate outliers.RESULTS: The homogeneity test index F<F_0.05(29,30)=1.84, indicated that there were no significant differences between the groups and within the group. No statistically significant changes were observed in 5 analyses during 22 months. The certified values of gold and arsenic in this series of certified reference materials (CRMs) were superior to those of the same level country-level gold ore RM and foreign arsenic-bearing polymetallic ore RM.CONCLUSIONS: This series of CRMs can be used as standards for the analysis and study of gold and arsenic in Carlin-type gold deposits.