硫酸氢钾沉淀分离—2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚光度法测定矿石中铅  

Determination of lead in ore by 2-[(5-bromine-2-pyridine)-azo]-5-diethylaminophenol spectrophotometry with potassium bisulfate precipitation separation

作　　者：王冀艳[1] 刘勉[1] 闫红岭[1] 连文莉[1] 张帆[1] 

机构地区：[1]河南省岩石矿物测试中心,河南郑州450001

出　　处：《冶金分析》2016年第4期71-75,共5页Metallurgical Analysis

基　　金：河南省国土资源厅"两权价款"项目(豫国土资函[2015]258号-01)

摘　　要：2-（5-溴-2-吡啶偶氮）-5-二乙氨基苯酚（5-Br-PADAP）光度法应用于矿石中铅的测定时，Cu、Zn、Fe、Ni、Bi、Mn、Cd、Co、V、Ti、Nb和Ta等多种元素的干扰不容忽视。针对这一问题，实验提出了采用KHS04沉淀法对样品进行前处理，5-Br-PADAP光度法测定矿石中Pb的方法。实验表明，采用盐酸-硝酸体系溶解矿石后，加入1OmL200g／LKHS04溶液，放置2Omin后即可见样品中的铅沉淀完全从而与上述离子分离；将沉淀过滤后，采用pH5．6的HAc-NaAc缓冲溶液溶解沉淀，可使K2S04·PbS04复盐沉淀溶解，从而与Ba、W、Sr和Ca等元素分离。在样品溶液中依次加入0．4mLpH9．3H3B03-KCl-NaOH缓冲溶液、O．4mL饱和KI溶液、O．4mL1O％（V：V）TrionX-100溶液、1．0mLO．03g／L5-Br-PADAP乙醇溶液，于1crn比色皿中，在波长558nm处进行测定，Pb质量浓度在O．O2～2肚g／mL范围内符合比尔定律，线性回归方程的相关系数为0．998。方法检出限为O．02肚g／mL。采用实验方法分别对铅矿、锌矿、铅锌矿标准物质中的Pb进行分析，测得结果与认定值基本一致，相对标准偏差（RSD，n=11）为2．3％～5．8％。During the determination of lead in ore by 2-[(5-bromine-2-pyridine)-azo]-5-diethylaminophenol(5-Br-PADAP)spectrophotometry,the interference of many elements(such as Cu,Zn,Fe,Ni,Bi,Mn,Cd,Co,V,Ti,Nb and Ta)could not be ignored.To solve this problem,the sample was pretreated by KHSO4 precipitation method.Then,the content of lead in ore was determined by 5-Br-PADAP spectrophotometry.The results showed that the lead in sample could be fully precipitated and separated from ions above by adding 10 mL 200g/L KHSO4 solution and placing for 20 min after dissolving the ore with hydrochloric acid-nitric acid system.After filtration,the K_2SO_4·PbSO_4composite salt precipitation was dissolved with HAc-NaAc buffer solution at pH 5.6,realizing the separation from Ba,W,Sr and Ca.Then,0.4mL of H_3BO_3-KCl-NaOH buffer solution at pH 9.3,0.4mL of saturated KI solution,0.4mL of 10%(V∶V)Trion X-100 solution and 1.0mL of 0.03g/L 5-Br-PADAP ethanol solution were added into sample solution successively.The content of lead was determined in 1cm cuvette at 558 nm.The Beer's law was obeyed for Pb with mass concentration in range of 0.02-2μg/mL.The correlation coefficient of linear regression equation was 0.998.The detection limit was 0.02μg/mL.The proposed method was applied to the determination of Pb in certified reference materials of lead ore,zinc ore and lead-zinc ore.The found results were basically consistent with the certified values.The relative standard deviations(RSD,n=11)were between 2.3% and 5.8%.

关 键 词：铅 光度法 2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP) 碘化钾 硫酸氢钾 礴石 

分 类 号：P575[天文地球—矿物学] O657.3[天文地球—地质学]