电感耦合等离子体原子发射光谱法测定石灰岩中游离二氧化硅  

Determination of free silica in limestone by inductively coupled plasma atomic emission spectrometry

作　　者：李海娟 杨林 隋东 邹国庆 费建亮 张行荣 LI Haijuan;YANG Lin;SUI Dong;ZOU Guoqing;FEI Jianliang;ZHANG Xingrong(CMGB Bu-1(Hebei)Analysis&Technology Co.,Ltd.,Langfang 065201,China;College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042,China)

机构地区：[1]中冶一局(河北)检测技术有限公司,河北廊坊065201 [2]青岛科技大学化工学院,山东青岛266042

出　　处：《冶金分析》2024年第3期53-58,共6页Metallurgical Analysis

摘　　要：标准方法GB/T 14840—2010采用热磷酸溶解石灰岩中的硅酸盐矿物,分离出游离二氧化硅,再用重量法测定其含量,操作较为繁琐。本文利用热磷酸可溶解硅酸盐矿物而几乎不溶解游离二氧化硅的特性分离出石灰岩中的游离二氧化硅,再以氟硼酸解聚已溶出的硅酸,用致密滤纸过滤,使游离二氧化硅与其他矿物完全分离;然后以热水洗涤沉淀3次,在银坩埚中灰化,用1.5 g氢氧化钠熔融、盐酸浸取后,选取Si 251.611 nm为分析谱线,用电感耦合等离子体原子发射光谱法(ICP-AES)测定试液中的二氧化硅,从而建立了石灰岩中游离二氧化硅的测定方法。方法中二氧化硅的校准曲线线性相关系数为0.9999,线性范围为0.024%~10.0%;方法检出限为0.008%,定量限为0.024%。按照实验方法测定4个石灰岩标准物质中游离二氧化硅,测定值与认定值的相对误差为-0.18%~0.48%,测定结果的相对标准偏差(RSD,n=12)为1.2%~1.9%。选取4个石灰岩样品,分别采用实验方法和标准方法GB/T 14840—2010中的重量法进行测定,以进行方法比对,二者测定结果基本一致。In standard method of GB/T 14840-2010,the silicate minerals in limestone are dissolved with hot phosphoric acid to separate free silica,then the content of free silica is determined by gravimetry.However,the operations are cumbersome and time-consuming.In this paper,free silica in limestone was separated from limestone by means of the property that hot phosphoric acid could dissolve silicate minerals but hardly dissolve free silica.Then,the dissolved silicic acid was depolymerized with fluoroboric acid.After filtration with dense filter paper,free silica could be fully separated from other minerals.Then the precipitates were washed with hot water for three times followed by ashing in silver crucible.After fusion with 1.5 g of sodium hydroxide and leaching with hydrochloric acid,the content of silica in sample solution was determined by inductively coupled plasma atomic emission spectrometry(ICP-AES)with Si 251.611 nm as analytical line.Consequently,a method for determination of free silica in limestone was established.The linear correlation coefficient of silica calibration curve was 0.9999,and the linear range was 0.024%-10.0%.The limit of detection and the limit of quantification were 0.008%and 0.024%,respectively.The contents of free silica in 4 certified reference materials of limestone were determined according to the proposed method,and the relative errors between the determination results and certified values were in range of-0.18%-0.48%.The relative standard deviations(RSD,n=12)were between 1.2%and 1.9%.The proposed method and the gravimetric method in standard method of GB/T 14840-2010 were applied in determination of 4 limestone samples for method comparison,and the determination results of the two methods were basically consistent.

关 键 词：石灰岩 电感耦合等离子体原子发射光谱法(ICP-AES) 游离二氧化硅 碱熔 

分 类 号：O657.31[理学—分析化学] TF031[理学—化学]