锂辉石和卤水中锂的液体阴极辉光放电快速检测方法研究及应用

发布时间：2018-02-26 09:00

本文关键词： 锂现场分析便携式Li-K分析仪盐湖卤水锂辉石　出处：《中国地质科学院》2017年硕士论文　论文类型：学位论文

【摘要】：锂资源作为一种重要的战略资源,对国民经济的发展意义重大,近年来越来越受到世界各国的重视。我国的锂资源主要集中在西藏、青海、四川、新疆、江西等偏远地区,将样品运送至实验室检测会消耗大量的人力与财力,因而急需建立针对锂资源中锂的快速、准确的现场分析方法,以节约分析成本,提高分析效率,实时指导锂资源勘查。目前,锂的检测方法主要有电感耦合等离子体发射光谱法、原子吸收光谱法、原子发射光谱法等,由于这些大型仪器需载气、燃气等气流条件,一般只能用于室内分析;而传统分析方法如重量法、容量法,操作复杂,检测周期长,难以实现快速分析的需求。便携式能量色散X射线荧光光谱法常应用于野外现场分析,但灵敏度低,不能分析轻元素Li。大气压液体阴极辉光放电发射光谱仪(SCGD-AES)可在大气压下工作,无需载气、燃气、助燃气和真空环境,不需要雾化装置,因而作为便携装置具有极大的优越性,已在环境、生物、食品等多种样品中金属离子的检测得到了广泛的应用。本论文采用大气压液体阴极辉光放电发射光谱技术,开展了盐湖卤水及锂辉石样品中锂的现场分析方法研究和应用示范。1)利用项目组自行开发的便携式Li-K分析仪建立了盐湖卤水中锂的分析方法。探讨了酸的种类及pH对Li信号强度的影响。本方法Li的检出限为4 ng/mL,精密度为1.7%(n=12),盐湖卤水(锂含量较高)中锂的Li-K分析仪测定值与ICP-MS测量值相对比,相对误差均小于2%。将建立的卤水中锂的分析方法应用于察尔汗盐湖的现场分析,Li-K分析仪的测定值与ICP-AES测量值相比,相对误差基本上均小于15%,满足野外现场分析的需求。2)利用便携式Li-K分析仪建立了锂辉石样品中锂的分析方法。优选酸消耗少、消解效率高、环境友好、具批量快速样品处理能力的微波消解技术对锂辉石样品进行前处理,在最优仪器条件下测量锂含量。锂辉石样品中锂的Li-K分析仪测定值与ICP-MS测量值相对比,相对误差均小于10%,满足锂辉石样品现场分析需求。3)初步研究盐湖卤水及锂辉石样品中存在的基体效应,研究发现盐湖卤水基体和锂辉石样品基体均在一定程度上抑制锂信号强度。并采用标准加入法克服了基体效应对锂测定的影响,经大量实验数据表明,采用2个点作标准加入法工作曲线即可获得较高的准确度,从而大大减少了工作量,提高野外现场样品的检测效率。4)为简化锂辉石样品前处理流程,优选耐氢氟酸的刚玉材质管,设计了内嵌式阴极-Li-K分析仪,并利用该装置分析测定了14种锂辉石样品中的锂含量。为避免高原极端环境下机械进样装置无法正常工作,设计了自流式进样-Li-K分析仪。利用改进的注射器进样-Li-K分析仪实现现场测定江西宜丰等地近200件花岗岩和伟晶岩样品中的锂含量。
[Abstract]:As an important strategic resource, lithium resources are of great significance to the development of the national economy and have attracted more and more attention in recent years. The lithium resources in China are mainly concentrated in remote areas such as Tibet, Qinghai, Sichuan, Xinjiang, Jiangxi, etc. Transporting samples to the laboratory will consume a lot of manpower and financial resources. Therefore, it is urgent to establish a rapid and accurate on-site analysis method for lithium in lithium resources in order to save the analysis cost and improve the analysis efficiency. At present, the detection methods of lithium mainly include inductively coupled plasma emission spectrometry, atomic absorption spectrometry, atomic emission spectrometry and so on. Traditional analytical methods such as gravimetric method, volumetric method, complex operation and long detection period are difficult to meet the requirement of rapid analysis. Portable energy dispersive X-ray fluorescence spectrometry is often used in field analysis. But because of its low sensitivity, it is not possible to analyze the light element Li.Atmospheric pressure liquid cathodic glow discharge emission spectrometer SCGD-AESs can work at atmospheric pressure without the need for carrier gas, gas, auxiliary gas and vacuum environment, and no atomization device. Therefore, as a portable device, it has been widely used in the detection of metal ions in many kinds of samples, such as environment, biology, food and so on. The field analysis method and application demonstration of lithium in salt lake brine and spodumene samples were carried out. The method of lithium analysis in salt lake brine was established by using portable Li-K analyzer developed by the project team. The effect of pH on the signal intensity of Li. The detection limit of Li is 4 ng / mL, the precision is 1. 7%, and the Li-K analyzer is compared with the ICP-MS measurement value in brine of salt lake (high lithium content). The relative errors are less than 2. The established method for the analysis of lithium in brine is applied to the field analysis of Chalhan Salt Lake. The measured value of Li-K analyzer is compared with that of ICP-AES. The relative errors are basically less than 15. The relative error is less than 15. 2) the method of lithium analysis in spodumene samples is established by using portable Li-K analyzer. The method has the advantages of low acid consumption, high digestion efficiency and environmental friendliness. The pretreatment of spodumene samples with microwave digestion technology with batch and rapid sample processing ability was carried out, and the lithium content was measured under the optimal instrument conditions. The Li-K analyzer measured lithium in spodumene sample was compared with the ICP-MS measurement value. The relative error is less than 10. The matrix effect in salt lake brine and spodumene sample is studied preliminarily. It is found that both the salt lake brine matrix and the spodumene sample matrix inhibit the lithium signal intensity to some extent, and the influence of the matrix effect on the determination of lithium is overcome by the standard addition method. Using two points as the standard adding method can get higher accuracy, thus greatly reducing the workload and improving the detection efficiency of field samples. 4) in order to simplify the pretreatment process of spodumene samples, A corundum tube with hydrofluoric acid resistance was selected, and an embedded cathode Li-K analyzer was designed, and the lithium content in 14 kinds of spodumene samples was determined by the device. A self-flow injection-Li-K analyzer was designed. The improved injector injector sample -Li-K analyzer was used to determine the lithium content in nearly 200 samples of granite and pegmatite in Yifeng and other places in Jiangxi province.
【学位授予单位】：中国地质科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;TS312;P585

【参考文献】