摘要
铝土矿中常伴有锂、镓、锆、稀土等有用组分,完全提取并准确测定其含量对于铝土矿资源综合评价和综合利用具有重要意义。然而铝土矿中常常含有少量刚玉,常规的四酸、五酸和封闭压力酸溶法对其分解不完全,导致测定结果偏低。本文采用氟化氢铵作熔剂,高温下在旋盖PFA小瓶中分解样品,通过在熔样过程中使用少量硫酸,对不同熔矿温度、消解时间及试剂用量等因素详细考察,确定了最佳熔矿条件[200℃,3h,试样比4∶1(称样量50mg)],建立了氟化氢铵分解-电感耦合等离子体质谱法测定含刚玉铝土矿中37种痕量元素的分析方法。本方法能快速、有效地分解含刚玉铝土矿,经三种铝土矿国家标准物质GBW07177、GBW07181和GBW07182验证,并与四酸、五酸和封闭压力酸溶法的测定结果对比,三种标准物质中Li、Ga、Sr、Zr、Pb等9种元素的回收率分别在95.0%~115.0%、90.0%~110.0%和90.0%~110.0%之间,测定值与认定值相符。同时,本方法实现了铝土矿(Al 2 O 3含量在42.97%~90.36%之间)中Al、Ti、P等主量元素的精确分析,进一步验证了其用来测定铝土矿中痕量元素的准确性。方法检出限为0.002~0.43μg/g,与传统硝酸-氢氟酸密闭消解法的检出限(0.000~0.48μg/g)基本相当,精密度在1.14%~8.84%之间,能够满足铝土矿中痕量元素的分析要求。
BACKGROUND:Bauxite is often accompanied by useful components such as lithium,gallium,zirconium,and rare earth metals.Complete extraction and accurate determination of the content of these components are of great significance for the comprehensive evaluation and comprehensive utilization of bauxite resources.However,bauxite often contains a small amount of corundum,which is not completely decomposed by the conventional four-acid,five-acid and closure pressure acid dissolution methods,resulting in lower measurement results.OBJECTIVES:To explore the new decomposition method to achieve rapid and accurate analysis of trace elements in corundum-bearing bauxite.METHODS:A digestion technique using the solid compound ammonium bifluoride in a screw-capped PFA vial at high temperature has been developed for trace elements analysis of corundum-bearing bauxite by using a small amount of sulfuric acid during the fusion process.The factors such as different melting temperature,digestion time and reagent dosage were investigated in detail,the optimal smelting conditions(200℃,3h,sample ratio 4∶1)were confirmed.An analytical method for determination of 37 trace elements in corundum-bearing bauxite by inductively coupled plasma-mass spectrometry with rapid decomposition of ammonium bifluoride was established.RESULTS:This method can be used to quickly and effectively decompose corundum-bearing bauxite,which has been verified by three national bauxite standard materials GBW07177,GBW07181 and GBW07182.The proposed method was also compared with the results of the four-acid,five-acid and closure pressure acid dissolution methods.The recoveries of nine elements such as Li,Ga,Sr,Zr and Pb in the three standard materials were from 95.0%to 115.0%,90.0%to 110.0%,and 90.0%to 110.0%,respectively.The analytical result was in agreement with the certified values.The detection limits of the method were from 0.002 to 0.43μg/g,which was closely equivalent to the detection limits(0.000-0.48μg/g)of the traditional nitric acid-hydrofluoric acid closure digestion method.The precisions were from 1.14%to 8.84%,which qualified it to meet the analytical requirements of trace elements in bauxite.CONCLUSIONS:This method can be used to achieve accurate analysis of major elements such as Al,Ti,and P in bauxite(Al 2 O 3 content between 42.97%and 90.36%),which further verifies the accuracy of this method for the determination of trace elements in bauxite.
作者
刘贵磊
许春雪
陈宗定
温宏利
LIU Gui-lei;XU Chun-xue;CHEN Zong-ding;WEN Hong-li(National Research Center for Geoanalysis,Beijing 100037,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2020年第5期670-681,共12页
Rock and Mineral Analysis
基金
中国地质调查局地质调查项目(DD20190323,DD20190475)
国家自然科学基金项目(21601041)。
关键词
氟化氢铵
快速分解
电感耦合等离子体质谱法
含刚玉铝土矿
痕量元素
ammonium bifluoride
rapid decomposition
inductively coupled plasma-mass spectrometry
corundum-bearing bauxite
trace elements
