硅钼黄分光光度法测定镍原矿中二氧化硅  

Determination of silica in nickel raw ore by silicon molybdenum yellow spectrophotometry

作　　者：刘晓丽 宁骏斌 李婷 韦犇犇 郭海珍 赵静静 LIU Xiaoli;NING Junbin;LI Ting;WEI Benben;GUO Haizhen;ZHAO Jingjing(Testing Center of the Jinchuan Group Limited Company,Jinchang 737100,China)

机构地区：[1]金川集团有限公司检测中心,甘肃金昌737100

出　　处：《冶金分析》2024年第7期81-87,共7页Metallurgical Analysis

摘　　要：硅含量是冶金过程的重要控制指标。本文以自产镍原矿为例,探讨了影响硅钼黄显色的实验条件,以及冶金样品中常见的Fe^(3+)、F^(-)干扰。样品经氢氧化钠熔融处理,干过滤后以滤后液为待测试液,用硫酸稳定酸度,加入钼酸铵溶液显色后即可测定吸光度。结果表明,保持适宜的显色酸度是测定的关键,且无需其他试剂加入。以二氧化硅计,校准曲线的线性范围为1.00%~40%;方法检出限约为1.00%。方法的表观摩尔吸光系数为1.1×10^(4)L·mol^(-1)·cm^(-1)。待测试液中F^(-)质量浓度大于65 mg/L即会对硅钼杂多酸显色产生影响;待测试液中Fe^(3+)质量浓度小于7.5 mg/L时对测定无影响。按照实验方法测定镍原矿中二氧化硅,测定结果的相对标准偏差(RSD,n=8)小于0.6%;回收率为95%~100%;二氧化硅质量分数为20%~40%时,估算误差为0.4%。本文还推荐了一种衡量样品与标准系列基体匹配的方法。Silicon content is an important control index in metallurgical process.In this paper,the self-produced nickel ore was used as an example to discuss the experimental conditions affecting the coloring of silicon molybdenum yellow as well as common interference of Fe^(3+)and F^(-)in metallurgical samples.The sample was treated by sodium hydroxide melting.The filtrate was taken as the solution to be tested after dry filtration.The acidity was stabilized with sulfuric acid,and the absorbance was measured after adding ammonium molybdate solution for coloring.The results showed that the maintaining of proper coloring acidity was the key to determination,and the addition of other reagents were unnecessary.Taking SiO_2 as the unit of measurement,the linear range of calibration curve was 1.00%-40%.The limit of detection was about 1.00%.The apparent molar absorption coefficient was 1.1×10^(4) L·mol^(-1)·cm^(-1).When the mass concentration of F^(-)in test solution was higher than 65 mg/L,it would influence on the coloring of silicon-molybdenum heteropoly acid.When the mass concentration of Fe^(3+)in test solution was less than 7.5 mg/L,it had no influence on the determination.The content of silica in nickel raw ore was determined according to the experimental method,and the relative standard deviation(RSD,n=8)of the determination results was less than 0.6%.The recoveries were between 95%and 100%.As the mass fraction of silica was in range of 20%-40%,the estimation error was 0.4%.Moreover,a method to measure the matching between samples and standard matrix series was also recommended in this study.

关 键 词：硅钼黄 分光光度法 酸度 氟离子 基体匹配 镍原矿 二氧化硅 

分 类 号：O657.32[理学—分析化学] TF031[理学—化学]