摘要
在采用自动电位滴定法对粗锡合金和废铅炉砖回收物料中Ag进行测定时,Cu的存在会产生干扰。实验探讨了用自动电位滴定测定时Cu对Ag的干扰,结果表明,用KI滴定不大于5mg Ag时,Cu最大允许量为100mg。据此,利用AgI沉淀溶度积最小的特性,建立了用KI自动电位滴定法测定粗锡合金和废铅炉砖回收物料中Ag的方法。用HCl-HNO3(1+3)溶样,以H2SO4冒烟除尽Cl-,在HNO3(1.6mol/L)-酒石酸(20g/L)-聚乙烯醇(0.2g/L)介质中,以0.6g抗坏血酸还原Fe3+为Fe2+,用复合Ag环电极和KI标准溶液(0.01mol/L)进行电位滴定。对滴定剂、指示电极、试样分解、酸介质、试剂用量和共存物质的影响等分析条件进行了实验优化。Ag量在1.0~50.0mg内与耗用KI标准溶液体积呈线性关系,相关系数为0.999 99,检出限(3s/k)为0.61μg。方法用于各试样中0.15%~31.69%Ag的测定,相对标准偏差(RSD,n=5~9)为0.79%~8.7%,加标回收率为85%~108%,测定值与火试金重量法结果相一致。
In this paper,copper(Cu)interference during silver(Ag)determination by automatic potentiometric titration of coarse tin alloy and waste lead furnace brick recycling material is discussed.The results showed that the maximum tolerant amount of Cu was 100 mg during potassium iodide(KI)titration for not higher than 5 mg of Ag.Based on minimum solubility product of AgI precipitation,an Ag determination method in coarse tin alloys and waste lead furnace brick recycling material by KI automatic potentiometric titration was established.The samples were dissolved in HCl-HNO 3(1+3)and Cl-was volatized out with H 2SO 4,in HNO 3(1.6 mol/L)-tartaric acid(20 g/L)-polyvinyl alcohol(0.2 g/L)medium,Fe 3+was reduced to Fe 2+using 0.6 g ascorbic acid and potentiometric titration was carried out using composite Ag ring electrode and KI(0.01 mol/L)standard solution.The experimental conditions including instrumental parameters,titrant,indicating electrode,sample decomposition,acidity media,reagents dosage and coexisting substances were optimized.The calibration curve of Ag content with KI standard titration volume was linear in the range of 1.0-50.0 mg with the correlation coefficient of 0.999 99 and the limit of detection(3 s/k)of 0.61μg.The method was applied to various samples with Ag content ranging from 0.15%to 31.69%.The relative standard deviation(n=5-9)was found to be 0.79%-8.7%and recoveries in the range of 85%-108%were obtained,which are in good agreement with fire assay gravimetric method results.
作者
赵如琳
石如祥
黄劲松
张红玲
ZHAO Rulin;SHI Ruxiang;HUANG Jinsong;ZHANG Hongling(Research and Designing Institute,Yunnan Tin Group Corporation,Gejiu,Yunnan 661000,China)
出处
《中国无机分析化学》
CAS
2018年第2期39-44,共6页
Chinese Journal of Inorganic Analytical Chemistry
基金
云南锡业公司研究设计院项目(2013-Y)
云锡铅业分公司废炉砖综合回收贵金属选矿试验项目资助
关键词
自动电位滴定法
碘化钾
粗锡合金
废铅炉砖
回收
银
automatic potentiometric titration
potassium iodide
crude tin alloy
waste lead furnace brick
silver(Ag)
