化学前处理—能量色散X射线荧光光谱法应用于矿石及水体现场分析

  本文关键词：化学前处理—能量色散X射线荧光光谱法应用于矿石及水体现场分析，由笔耕文化传播整理发布。

        能量色散-X射线荧光光谱法(EDXRF)在矿产勘查、矿山环境监测及找矿现场分析中具有重要地位。包括硫化物矿石在内的高矿化度地质样品,由于缺乏基体匹配的标准样品,存在分析校准问题,基体校正难度也很大,分析数据的准确度会受到严重影响,制约了EDXRF在该类样品分析中的应用；分散在水体中的、对生态环境和人类健康危害较大的重金属元素,由于其元素浓度一般低于EDXRF仪器检出限而无法检出。为了满足矿产勘查现场对高矿化度及矿石样品准确、可靠分析的需要,以及水体中重金属浓度现场监测分析的需求,急需开发与分析对象相配套的EDXRF制样、分析方法。本文针对富含硫化物矿物的高矿化度样品及矿石样品,采用了酸消解的溶液制样方法；针对水样中较低浓度重金属采用了离子交换纸动态富集制样方法,结合EDXRF技术,建立了硫化物矿石和多金属矿石中铜、铅、锌元素分析方法各一套；研制了适合水样中铜、铅、锌、镍等元素富集制样的离子交换纸及动态富集装置,开展了交换富集试验。具体实验方案与实验结论如下：(1)硝酸+氢氟酸封闭消解试样,络合缓冲溶液定容、进样,标准溶液校准-偏振能量色散-X射线荧光光谱(PE-EDXRF)同时测定硫化物矿石样品中铜、铅、锌三种元素。确定了消解与测量方法,用GBW07162～GBW07168七种矿石国家一级标准物质对该方法进行了验证。结果表明,当样品中Cu、Zn、Pb元素含量大于1%时,几乎所有样品中的铜、铅、锌元素的精密度值(RSD, n=6)优于5%,检测结果与标准值一致性良好。该方法是对EDXRF测量进样方式的一种探索,是对实验室矿石分析技术的扩充,也为现场矿石分析奠定了基础。(2)在祁曼塔格多金属矿区现场试验了“水浴加热+王水在比色管中消解样品”及“电热板加热+盐酸、硝酸顺序消解+硝酸提取”两种样品处理方式,使用专门研制的具有双层薄膜结构的液体样品盒,标准溶液进行校准,PE-EDXRF同时测定了铜、铅、锌三种元素。对这两种酸消解方法制备的样品进行分析时,均采用二级靶Mo Kα谱线的康普顿散射峰作为内标校正基体效应。采用现场电热板加热方式,分析二件矿区样品的方法精密度(RSD,n=10)均优于2%,分析四件管理样获得的分析相对误差均优于5%(当含量>0.5%时),十三件矿区未知样品PE-EDXRF与原子吸收分光光度法(AAS)平均相对偏差分别为2.87%、2.82%、6.84%。在高海拔地区(海拔大于4000米)使用“水浴加热+王水在比色管中消解样品”法存在分析结果系统偏低问题,但实验数据用地质管理样进行修正后,可以得到满意的结果。试验证明,采用研制的双层膜液体样品盒,可以直接测定强酸性液体样品,不会产生泄漏、挥发等造成的仪器损坏。用两种现场样品酸消解技术所建立的PE-EDXRF分析方法,克服了基体匹配标样缺乏的问题,解决了高矿化度样品及矿石样品的现场较高精度分析问题,是对粉末制样法PE-EDXRF现场分析技术的一个补充和改善,丰富了车载EDXRF技术的现场分析能力。(3)研制了具有富集水体样品中铜、铅、锌、镍等重金属元素能力的离子交换特种纸片,经交换富集后的纸片可直接用于EDXRF测量。研制了具有动态交换富集功能的交换富集装置。对混合标准溶液和单元素标准溶液进行的富集实验表明,铜、锌、镍的检出限达到几个ng/mL,铅的检出限达到约20ng/mL,为EDXRF应用于现场水体重金属监测奠定了基础。本研究形成的成果包括已被《岩矿测试》(核心期刊)接受的研究论文2篇,已被国家知识产权局批准(公示中)的实用新型专利3项。通过本研究,使车载EDXRF技术对勘查找矿和环境监测工作现场分析支撑能力获得提升。

    Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) is a popular on-site analytical technique in mineral prospecting, mine environment monitoring. Lack of sufficient matrix matching calibration samples has been a major problem affecting the accuracy and reliability of on-site EDXRF analysis for highly mineralized samples and metal ores including sulfides. Moreover, the relatively low sensitivity of portable or transportable EDXRF spectrometers prohibit their direct use in on-site monitoring of heavy metals in surface and underground water samples in which the concentrations of heavy metals are far below the detection limits of the technique. Meanwhile, laboratory wet chemical analysis techniques and many preconcentration methods have made substantial developments, which offer opportunity for EDXRF to rely on chemical pretreatment process to overcome the above problems. In this work, two sets of experiments were carried out to establish on-site EDXRF methods for:1) accurate ore forming element analysis of multi-metallic ore after acid digestion of samples;2) heavy metal analysis in water samples after enrichment with ion exchange resin loaded filter paper specially made for the work. Experimental procedures and results are as follows:(1) Sealed digestion of samples by nitric acid and hydrofluoric acid, and EDXRF calibrations were done by utilizing standard solutions. Copper, lead and zinc in sulfide samples were quantified. The established method was verified with seven certified reference materials of multi-metallic ores GBW07162-GBW07168. Results show that almost all the precisions for copper, lead, zinc are better than5%(RSD, n=6),when their concentrations are greater than1%, and the results are in good consistency with the standard values.(2)Combined with the PE-EDXRF, two different procedures of ore sample digestion were tested on-site on multi-metallic ores for Cu, Pb Zn analysis:1)digestion in glass tubes in water bath with aqua regia,2) digestion in glass beakers on a hot plate with sequential adding of hydrochloric acid and nitric acid. These methods were calibrated by standard solutions and Compton scattering intensities of Mo Ka from the secondary target used as internal standard to compensate for the matrix effect. Two kinds of double cabin sample cups with acid absorbent and double supporting films were developed to prevent the spectrometer from damage by the possible leakage and evaporation in Qimantage area, Qinghai province(More than4000meters). When samples were pretreated using procedure2, the relative standard deviations (RSD, n=10) were less than2%for2quality control samples and relative errors were less than5.0%(element concentration were higher than0.5%) for4ones. PE-EDXRF results were compared with Atomic Absorption Spectroscopy(AAS) ones, the obtained mean relative deviation for Cu Pb and Zn were2.87%、2.82%、6.84%for the13local mine unknown samples. We conclude that the vehicle-loaded PE-EDXRF coupled with the double cabin sample cups and sample digestion procedures can solve the problem of matrix matching and offer a satisfactory solution for high precision on-site poly-metallic ore sample analysis. The work expand the capability of PE-EDXRF on-site analysis and improve the already established powder sample preparation method.(3) Ion exchange resin loaded filter papers were made, which were cut to fit the sample cups in the instrument before enrichment procedures. An ion exchange device was specially designed to allow repeated dynamic ion exchange without solution blending between repetitions. Primary ion exchange test and EDXRF measurement showed that the detection limits were as low as several ng/mL for Cu, Zn and Ni and about20ng/mL for Pb. Though the work is on its way yet, it has opened a door for the on-site EDXRF application in water quality monitoring.The above work has paved the way for the extended on-site application of portable and transportable EDXRF for mineral source exploration and water quality survey. The results has been summarized into two academic papers which have been accepted by the journal <Rock and mineral Analysis>, and three patents which are in the course of publicity.

化学前处理—能量色散X射线荧光光谱法应用于矿石及水体现场分析

摘要5-7Abstract7-8第一章 绪论10-21    1.1 X射线荧光光谱技术分析进展10-18    1.2 课题的学术背景及研究意义18-20    1.3 选题目的与主要内容20-21第二章 X射线荧光光谱法基本原理21-54    2.1 X射线概论21-26    2.2 特征X射线荧光26-28    2.3 X射线的吸收与散射28-31    2.4 X射线荧光光谱分析的特点31-32    2.5 能量色散X射线荧光光谱技术32-37    2.6 偏振能量色散X射线光谱仪37-39    2.7 X射线荧光光谱定性分析39-40    2.8 X射线荧光光谱定量分析40-44    2.9 X射线荧光光谱分析制样技术44-49    2.10 X射线荧光光谱技术分类49-52    2.11 本章小结52-54第三章 酸消解-络合缓冲溶液EDXRF分析硫化物矿石样品54-61    3.1 实验部分54-56    3.2 结果与讨论56-60    3.3 结论60-61第四章 酸消解-车载EDXRF现场分析多金属矿石样品61-71    4.1 祁曼塔格找矿远景区61-62    4.2 双层膜液体样品盒研制62-63    4.3 实验部分63-66    4.4 结果与讨论66-70    4.5 结语70-71第五章 离子交换特种纸富集水体重金属元素的初探71-86    5.1 离子交换特种纸制备71-72    5.2 富集装置72-73    5.3 实验部分73-75    5.4 结果与讨论75-84    5.5 小结84-86结论86-88致谢88-90参考文献90-99个人简历99

  本文关键词：化学前处理—能量色散X射线荧光光谱法应用于矿石及水体现场分析，，由笔耕文化传播整理发布。