铋试金-石墨炉原子吸收光谱法测定黑色页岩中痕量金铂钯  

Determination of trace gold,platinum and palladium in black shale by graphite furnace atomic absorption spectrometry with bismuth fire assay

作　　者：毛香菊[1,2,3] 姚明星 郭晓瑞[1,2,3] 王甜甜 倪文山 程诚 MAO Xiangju;YAO Mingxing;GUO Xiaorui;WANG Tiantian;NI Wenshan;CHENG Cheng(Zhengzhou Institute of Multipurpose Utilization of Mineral Resources,CAGS,Zhengzhou 450006,China;China National Engineering Research Center for Utilization of Industrial Minerals,Zhengzhou 450006,China;Key Laboratory for Polymetallic Ores'Evaluation and Utilization,MNR,Zhengzhou 450006,China;Paris-Saclay University,Paris 91400,France)

机构地区：[1]中国地质科学院郑州矿产综合利用研究所,河南郑州450006 [2]国家非金属矿资源综合利用工程技术研究中心,河南郑州450006 [3]自然资源部多金属矿评价与综合利用重点实验室,河南郑州450006 [4]巴黎萨克雷大学,法国巴黎91400

出　　处：《冶金分析》2023年第8期24-30,共7页Metallurgical Analysis

基　　金：国家自然科学基金项目(22106148);中国地质调查局地质调查二级项目(DD20221782)。

摘　　要：黑色页岩中Au、Pt和Pd含量较低且分布不均匀,因此测定时需要辅以合适的分离富集方法。本文通过矿物解离度分析仪研究了黑色页岩样品的组成结构;利用Ag能与Au、Pt和Pd形成合金的原理,以Bi2O3作为捕集剂,在试金配方中添加Ag作为保护剂进行熔融,增加了铋扣的稳定性;同时在试金配料中加入KNO3以将基体中的S氧化成硫酸盐进入熔渣;得到的铋扣经过灰吹可得到银合粒,据此,实现了对黑色页岩中Au、Pt和Pd的分离富集。采用先加入HNO3再加入HCl的方式溶解银合粒,建立了石墨炉原子吸收光谱法(GF-AAS)测定黑色页岩中Au、Pt和Pd的方法。对试金配料中面粉和Bi_(2)O_(3)的用量进行了优化,确定采用8 g面粉和100 g Bi_(2)O_(3)。试验表明,在试金配方中加入200μL 20 g/L Ag银标准溶液,在Bi完全吹尽后,形成的银合粒形状规则、光滑圆整、大小适中,未出现散珠现象。在选定的实验条件下,用Au、Pt和Pd的吸光度与其对应的质量浓度绘制校准曲线,决定系数为0.9997~0.9999,特征浓度为0.338~2.15 ng/mL。将实验方法应用于黑色页岩贵金属成分分析标准物质中Au、Pt和Pd的测定,测定值与认定值基本一致。按照实验方法对贵州省纳雍地区的黑色页岩样品进行精密度和加标回收试验,测定结果的相对标准偏差(RSD,n=6)在3.1%~5.1%之间,加标回收率在92%~109%之间。The contents of Au,Pt and Pd in black shale are relatively low and their distribution is nonuniform.Therefore,a suitable separation and enrichment method should be auxiliary for determination.The composition and structure of black shale samples were analyzed by mineral liberation analyzer.Based on the principle that Ag could form alloys with Au,Pt and Pd,Ag was added as a protective agent to the fire assay ingredient for melting with Bi2O3 as collector,which enhanced the stability of bismuth button.Meanwhile,KNO3 was added into the fire assay ingredient to oxidize S in matrix to sulfates,which entered into melting slag.The resultant bismuth button was treated by cupellation,and the silver composite granule was obtained.Therefore,the separation and enrichment of Au,Pt and Pd in black shale were realized.After the silver composite granule was dissolved by adding HNO_(3) and then HCl,a method for the determination of Au,Pt and Pd in black shale was established by graphite furnace atomic absorption spectrometry(GF-AAS).The dosages of flour and Bi_(2)O_(3) in the fire assay ingredient were optimized,then 8 g of flour and 100 g of Bi_(2)O_(3) were used.The results showed that when 200μL of 20 g/L Ag standard solution was added into the fire assay ingredient,the formed silver composite granule had regular shape,smooth surface and moderate size without loose bead phenomenon after Bi was blown completely.Under the selected experimental conditions,the calibration curves were drawn with the absorbances of Au,Pt and Pd and their corresponding mass concentrations.The correlation coefficients were between 0.9997 and 0.9999.The characteristic concentrations were between 0.338 ng/mL and 2.15 ng/mL.The proposed method was applied for determination of Au,Pt and Pd in certified reference material of black shale for composition analysis of precious metals.The results were basically consistent with the certified values.The precision and recovery tests of black shale samples from Nayong Area of Guizhou Province were conducted accordi

关 键 词：铋试金 黑色页岩 金 铂 钯 石墨炉原子吸收光谱法(GF-AAS) 氧化铋 硝酸钾 

分 类 号：O657.31[理学—分析化学] TF031[理学—化学]