| Lithium is regarded as one of the "New Energy Resources"and also a significant kind of national strategic resources.For environment-friendly and sustainable development of economy,an increasing quantity demantded for Lithium is predicted.Lithium resource exploration will paly an important part in future decades.However,Li resources in China are mainly distributed in remote or plateau regions such as Tibet,Qinghai,Sichuan,Xinjiang and Jiangxi.It will take a lot of manpower,material cost and financial burdan to transport the samples to laboratories and determine the results of Li.Therefore,it is urgent to establish a rapid,accurate method to determine Li in lithium resources,so as to provide on-site Lithium data to support Li resource explpration work in time.At present,determination methods of Li include inductively coupled plasma atomic emission spectrometry,flame atomic absorption spectrometry,flame atomic emission spectrometry.Due to these large equipments require carrier gas,fuel gas and other auxiliary gas flow conditions,they are only suitable in laboratory.And the traditional analytical methods such as gravimetric method and volumetric method cannot reach the purpose of rapid analysis owing to the disadvantages of fussy operation process and longtime of measurement.Portable energy dispersive X-ray fluorescence spectrometry(ED-XRF)is the preferred analytical technology in the field,but it cannot analyze the light elements such as Li because of the principle limit of the technique.Solution-cathode glow discharge-atomic emission spectrometry(SCGD-AES)has been used to determine metal ions in a lot of fields including environmental,medical and food safety.As a portable device,it can be run under atmospheric pressure,without plasma carrier gas,fuel gas,vacuum environment,atomization device.In this paper,based on the SCGD-AES,the on-site analytical method was established to analyze Li in salt lake brines and spodumene samples.1)A rapid method for analysis of Li in salt lake brine samples was established by the self-designed portable Li-K analyzer.The effects of selected acid and pH on the signal intensity of Li were investigated.The limit of detection of Li was 4 ng/mL and the precision is 1.7%(n = 12)of the method.The relative error(RE)of determined values of Li in brines by Li-K analyzer and ICP-MS measurements were all less than 2%.The established analytical method of Li in brines was applied to the on-site analysis of Chaerhan salt lake.The relative error(RE)of determined values of Li in brines by Li-K analyzer and ICP-MS measurements were almost less than 15%,which could meet the requirement for on-site determination of Li in salt lake brines.2)A rapid method for analysis of Li in spodumene samples was established by the self-designed portable Li-K analyzer.The spodumene samples were pretreated with microwave digestion techniques with low acid consumption,high digestion efficiency,environment friendly and rapid batch processing capacity,then the content of lithium in spodumene samples were measured under the optimum instrument conditions.The determined values of Li in spodumene samples by Li-K analyzer were compared with those measured by ICP-MS,and the relative error was less than 10%,which could meet the demand for on-site analysis of spodumene samples.3)The existed matrix effect of salt lake brines and spodumene samples preliminarily established.The analytical results showed that the salt lake brine matrix and spodumene sample matrix can suppress the signal intensity of lithium to a certain extent.And the standard addition method was used to overcome the influence of matrix effect on the determination of lithium.After a large number of experimental data,it is shown that standard addition method could reach relatively high accuracy using only 2 addition points,which could greatly reduce the workload and improve the analytical efficiency of on-site analysis.4)In order to simplify the pretreatment process of spodumene sample,the corundum tube which could tolerate hydrofluoric acid was selected,the embedded cathode-Li-K analyzer was designed and was applied to the determination of lithium in 14 kinds of spodumene samples.In order to avoid the mechanical injection device problems in extreme environment,the self-flow injection-Li-K analyzer was designed.The determination of lithium in nearly 200 granite and pegmatite samples was measured by the improved syringe injection-Li-K analyzer on-site. |
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