Plasma diagnostics by optical emission spectroscopy on manganese ore in conjunction with XRD, XRF and SEM-EDS

Manganese(Mn) is an important industrial mineral.Information about the chemical and phase constitution along with the concentration of impurities presented in Mn ore is compulsory in assessing its suitability for different applications.We performed the qualitative and quantitative analysis of low-grade Mn ore(LGMO) using laser-induced breakdown spectroscopy(LIBS) in conjunction with x-ray diffraction(XRD), x-ray fluorescence(XRF) and scanning electron microscopy(SEM) coupled with energy dispersive x-ray electron spectroscopy(EDS).The optical emission spectra of the LGMO sample displayed the presence of Mn, Si, Ca, Fe, Al, Mg,V, Ti, Sr, Ni, Na, Ba and Li.The plasma parameters, electron temperature and number density were estimated using the Boltzmann plot and Stark broadening line profile methods and were found to be 7500 K±750 K and 8.18±0.8×1017 cm-3, respectively.Quantitative analysis was performed using the calibration-free LIBS(CF-LIBS) method and its outcome along with XRD, XRF and SEM-EDS data showed almost analogous elemental composition, while the LIBS method gave acceptably precise elemental analysis by detecting the low atomic number element Li besides V and Sr.The results obtained using LIBS for the LGMO exhibited its ability as a powerful analytical tool and XRF, XRD and SEM-EDS as complementary methods for the compositional analysis of complex low-grade mineral ore.

A comparison among optical emission spectroscopic methods of determining electron temperature in low pressure argon plasmas

In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas of dc glow discharges at low pressures in laboratory by measuring the relative intensities of ArI lines at various pressures. These methods are developed respectively on the basis of the Fermi-Dirac model, corona model, and two kinds of electron collision cross section models according to the kinetic analysis. Their theoretical bases and the conditions to which they are applicable are reviewed, and their calculation results and fitting errors are compared with each other. The investigation has indicated that the electron temperatures obtained by the four methods become consistent with each other when the pressure increases in the low pressure argon plasmas.

Investigation on plasma characteristics in a laser ablation pulsed plasma thruster by optical emission spectroscopy

In order to further improve the propulsion performance of pulsed plasma thrusters for space micro propulsion,a novel laser ablation pulsed plasma thruster is proposed,which separated the laser ablation and electromagnetic acceleration.Optical emission spectroscopy is utilized to investigate the plasma characteristics in the thruster.The spectral lines at different times,positions and discharge intensities are experimentally recorded,and the plasma characteristics in the discharge channel are concluded through analyzing the variation of spectral lines.With the discharge energy of 24 J,laser energy of 0.6 J and the use of aluminum propellant,the specific impulse and thrust efficiency reach 6808 s and 70.6%,respectively.

Measurement of electron density and electron temperature of a cascaded arc plasma using laser Thomson scattering compared to an optical emission spectroscopic approach

As advanced linear plasma sources, cascaded arc plasma devices have been used to generate steady plasma with high electron density, high particle flux and low electron temperature. To measure electron density and electron temperature of the plasma device accurately, a laser Thomson scattering（LTS） system, which is generally recognized as the most precise plasma diagnostic method, has been established in our lab in Dalian University of Technology. The electron density has been measured successfully in the region of 4.5？×10^19m^-3 to7.1？×10^20m^-3 and electron temperature in the region of 0.18 eV to 0.58 eV. For comparison,an optical emission spectroscopy（OES） system was established as well. The results showed that the electron excitation temperature（configuration temperature） measured by OES is significantly higher than the electron temperature（kinetic electron temperature） measured by LTS by up to 40% in the given discharge conditions. The results indicate that the cascaded arc plasma is recombining plasma and it is not in local thermodynamic equilibrium（LTE）. This leads to significant error using OES when characterizing the electron temperature in a non-LTE plasma.

Time-Resolved Optical Emission Spectroscopy Diagnosis of CO_2 Laser-Produced SnO_2 Plasma

The spectral emission and plasma parameters of SnO2 plasmas have been investigated. A planar ceramic SnO2 target was irradiated by a CO2 laser with a full width at half maximmn of 80 ns. The temporal behavior of the specific emission lines from the SnO2 plasma was characterized. The intensities of Sn I and Sn Ⅱ lines first increased, and then decreased with the delay time. The results also showed a faster decay of Sn I atoms than that of Sn II ionic species. The temporal evolutions of the SnO2 plasma parameters （electron temperature and density） were deduced. The measured temperature and density of SnO2 plasma are 4.38 eV to 0.5 eV and 11.38×1017 cm 3 to 1.1×1017^ cm-3, for delay times between 0.1 μs and 2.2 #s. We also investigated the effect of the laser pulse energy on Sn02 plasma.

Determination of Non-Maxwellian Electron Energy Distributions in Low-Pressure Plasmas by Using the Optical Emission Spectroscopy and a Collisional-Radiative Model

A Maxwellian electron energy distribution function （EEDF） is often assumed when using the optical emission line-ratio method to determine the electron temperature in low- temperature plasmas. However, in many cases, non-Maxwellian EEDFs can be formed due to the non-local electron heating or the inelastic-collisional energy loss processes. In this work, with a collisional-radiative model, we propose an approach to obtain the non-Maxwellian EEDF with a ＇two-temperature structure＇ from the emission line-ratios of Paschen 2p levels of argon and kryp- ton atoms. For applications of this approach in reactive gas （CF4, O2, etc） discharges that contain argon and krypton, recommendations of some specific emission line-ratios are provided, according to their sensitivities to the EEDF variation. The kinetic processes of the relevant excited atoms are also discussed in detail.

Characteristics of Laser Produced Plasmas Obtained by Fast ICCD Photography, Schlieren Photography and Optical Emission Spectroscopy

Pulsed laser produced plasmas(LPP)are important for industrial applications and fundamental researches,and their complex,multi-physical and cross-chemical processes need to be investigated more comprehensively.In this work,images of the luminous plasma,the spatial density distribution,and the plasma parameters are experimentally investigated by using fast ICCD photography,schlieren photography,and optical emission spectroscopy.Plasmas are produced by a 1 064 nm,15 ns Nd:YAG laser.Free expanding and splitting phenomena are observed in vacuum(at the pressure of about 1×10 3Pa)and air(at the pressure of 20 Pa)using fast photography,respectively.Meanwhile,shock waves formed in the atmospheric laser produced plasma are visualized by schlieren photography.The formation of shock waves is interpreted with the Sedov-Taylor theory,and an averaged expansion velocity about 375 m/s of the shock waves is estimated during 200～1 000 ns.Atmospheric air is found to have significant confinement effects on the plasma expansions compared to that in vacuum or low pressure ambient.Based on the optical emission spectroscopy,after 1 000 ns,at 0.6 mm above the target,the plasma temperature is about 7 800 K and the electron number density is approximately 0.64×1016cm-3.

Optical Emission Spectroscopic Studies of ICP Ar Plasma

The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced by an inductively coupled plasma （ICP） were measured by optical emission spectroscopy and the influences from the working gas pressure, radio-frequency （RF） power and different positions in the discharge chamber on the line intensities were investigated in this study. It was found that the intensity of Ar atom line increased firstly and then saturated with the increase of the pressure. The line intensity of Ar^＋, on the other hand, reached a maximum value and then decreased along with the pressure. The intensity of the line in an RF discharge also demonstrated a jumping mode and a hysteresis phenomenon with the RF power. When the RF power increased to 400 W, the discharge jumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a sudden increase, while the intensity of Ar^＋ ion only changed slightly. If the RF power decreased from a high value, e.g., 1000 W, the discharge would jump from the H-mode back to the E-mode at a power of 300 W. At this time the intensities of Ar and Ar^＋ lines would also decrease sharply. It was also noticed in this paper that the intensity of the ion line depended on the detective location in the chamber, namely at the bottom of the chamber the line was more intense than that in the middle of the chamber, but less intense than at the top, which is considered to be related to the capacitance coupling ability of the ICP plasma in different discharge areas.

Optical Emission Spectroscopic Study During the Evaporation of Aluminium in the Thermal Plasma Reactor

The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-O with that of Al follows the exact trend as of that obtained from the corresponding line intensities in X-ray diffraction spectra of the synthesized samples. In this paper the inherent capacity of emission spectroscopy in evaluating the growth processes under plasma induced reactions is presented.

Characteristics of C_2 Radical in CHF_3 and CF_4 Electron Cyclotron Resonance Plasmas Studied by Optical Emission Spectroscopy

The characteristics of CHF3 and CF4 electron cyclotron resonance (ECR) plasma have been studied by optical emission spectroscopy (OES) and Langmuir probe. It is found that C2 radical is one of main compositions in both of the two plasmas. We investigated the relative concentration of C2 radical as a function of F (H) radical and ion density. The formation mechanism of C2 radical is analyzed.

Analysis of optical emission spectroscopy data during silicon etching in SF_(6)/O_(2)/Ar plasma

Silicon etching is an essential process in various applications,and a major challenge for etching process is anisotropic high aspect ratio etching characteristics.The etch profile is determined by the plasma parameters and process parameters.In this study,the plasma state with each process parameters were analyzed through the optical emission spectroscopy(OES)plasma diagnostic sensor by both chemical and physical approaches.Electron temperature and electron density were additionally acquired using the corona model with OES data that provides chemical species information,and the etch profile was evaluated through scanning electron microscope measurement data.The results include changes in profile with gas ratio,bias power,and pressure.We figure out that factors like ion energy and ion angular distribution as well as chemical reaction affect the anisotropic profile.

Diagnostics of Argon Inductively Coupled Plasma and Dielectric Barrier Discharge Plasma by Optical Emission Spectroscopy

An experimental setup was built up to carry out radio frequency (RF) inductively coupled plasma (ICP) and dielectric barrier discharge (DBD), and to depict the optical emission spectra (OES) of the discharges. OES from argon ICP and DBD plasmas in visible and near ultraviolet region were measured. For argon ICP, the higher RF power input (higher than 500 W for our machine), the higher degree of argon plasma ionization. But that doesn't mean a higher mean electron energy. With the increase in the power input, the mean electron energy increases slightly, whereas the density of electron increases apparently On the contrary, argon DBD discharge behaves in the manner of a pulsed DC discharge on optical emission spectroscopy and V-I characteristics. DBD current is composed of a series of pulses equally spaced in temporal domain. The Kinetics of DBD emission strength is mainly governed by the frequency of the current pulse.

Optical Emission Spectroscopic Measurement of Hydroxyl Radicals in Air Discharge with Atomized Water

Effects of discharge mode, voltage applied, size of the nozzle discharge electrode and flow rate of water on the generation of hydroxyl radical were investigated in air discharge with atomized water, by using optical emission spectroscopy （OES）. Water was injected into the discharge region through the discharge nozzle electrode, and a large amount of fine water drops, formed and distributed in the discharge region, corona discharge was more effective to generate were observed. It was found that negative DC the hydroxyl radicals in comparison to positive DC corona discharge or negative pulsed discharge. A larger outer diameter of the nozzle electrode or a stronger electric field is beneficial for hydroxyl-radical generation. Moreover, there is a critical value in the flow rate of atomized water against the discharge voltage. Below this critical value, hydroxyl-radical generation increases with the increase in flow rate of the water, while above this value, it decreases. In addition, it is observed that OES from the discharge is mainly in the ultraviolet domain. The results are helpful in the study of the mechanism and application of plasma in pollution-control in either air or water.

Measurement of the O_2 Dissociation Fraction in RF Low Pressure O_2/Ar Plasma Using Optical Emission Spectrometry

Measurement of the oxygen dissociation fraction in RF low pressure oxygen/argon plasma using optical emission spectrometry is presented. The oxygen dissociation fraction and its evolutions as functions of operational parameters were determined using argon as the actinometer. At a pressure of 30 Pa, the oxygen dissociation fraction decreased from 13.4% to 9.5% as the input power increased from 10 W to 70 W. At an input power of 50 W, the oxygen dissociation fraction decreased from 12.3% to 7.7% when the gas pressure increased from 10 Pa to 40 Pa. The influences of operational parameters on the generation of atomic oxygen were also discussed.

微波消解-电感耦合等离子体发射光谱(ICP-OES)法测定固体中兽药制剂中金属元素

传统的中兽药制剂中金属元素检测主要为原子吸收光谱法或原子荧光光谱法等单一元素检测方法,为提高检测效率,实现对固体中兽药制剂中金属元素的准确测定,使用硝酸-过氧化氢及微波消解进行样品前处理,消解后置消解管于赶酸仪中170℃赶酸,采用微波消解-电感耦合等离子体发射光谱(ICP-OES)法相结合对固体兽药制剂中铬、砷、镉、铅、钠、镁、钾、锰、铁、铜、锌、硒、钙、磷等14种元素同时测定,轴向观测方向,内标法定量。消解及赶酸效果理想,整个过程安全、高效、无损。对消解方式进行了考察,并对消解酸体系及消解温度进行了优化,选择了最优的赶酸温度及元素分析谱线,同时也通过试剂加标回收、样品加标回收、样品处理液加标回收相比较的方式验证了方法的可行性。结果表明,铅、镉、铬、砷在0.001~0.01μg/mL,锰、铜、硒在0.002~0.02μg/mL,铁、锌在0.1~1.0μg/mL,镁、钙在1.0~10.0μg/mL,钠、钾、磷在2.0~50.0μg/mL线性关系良好,相关系数(r)均大于0.999,各元素方法检出限在0.1~1.0 mg/kg,平均回收率在90.0%~110%,精密度RSD小于10%(n=5)。方法前处理简便快捷、干扰小、重现性好、灵敏度高,可同时测定多种元素,满足批量测定固体中兽药制剂中铬、砷、镉、铅、钠、镁、钾、锰、铁、铜、锌、硒、钙、磷等14种元素定量分析的要求。

基于ICP-OES评估口服抗糖产品中金属元素健康风险

以口服抗糖产品为研究对象,建立电感耦合等离子体发射光谱法(ICP-OES),同时测定样品溶液中铬、镁和锌含量.结果表明,在一定浓度范围内,各元素线性相关系数均为0.9999,平均加标回收率为88.21%~97.95%;检出限为0.0006~0.0033μg/mL,精密度为0.25%~0.55%;表明该方法简便、准确,精密度高.同时,依据国家相关标准的规定对测试结果进行分析,得到3种金属元素的健康风险评估,其含量均在安全范围之内,并给出了饮用建议,即需注意铬的总摄入量.

ICP-OES法测定磷铁中硅、锰、钛、钒、铬元素

针对目前电感耦合等离子体发射光谱法(ICP-OES)测定磷铁样品杂质元素含量存在的样品溶解问题,本文采用氢氧化钠+碳酸钠对被检测磷铁进行一次熔样,然后使用电感耦合等离子体发射光谱仪对样品中的硅、锰、钛、钒、铬进行测定。测定结果表明,本文测定各元素检出限为0.0016%~0.0080%,测定下限为0.0064%~0.032%,结果与标准样品各元素含量相对误差RE均小于5%,加标回收率为95.1%~102.4%,相对标准偏差小于5%,且三个实际样品RSD均小于5%,故表明此方法精密度及准确度良好,能够满足检测要求。该方法克服了磷铁样品难溶解的特点,并在短时间内获得理想检测结果,而且测定结果具有很高稳定性、精密度和准确度。本试验方法具有可重复性,流程短、成本低,适用于大批量样品的快速分析,可成为检测磷铁产品的一种更简单、快速、经济的重要手段。

利用ICP-OES测定磷酸铁锂中复杂金属杂质的方法实践

随着锂离子电池产业的蓬勃发展,废旧锂离子电池及锂离子电池生产过程中的报废体量剧增,锂离子电池相关的回收产业发展迅猛,其中磷酸铁锂电池的市场最大。无论哪种回收路径,回料中的金属杂质成分都比较复杂,而金属杂质的准确测定,对锂离子电池回收产业至关重要。文中通过高温热解法对样品进行前处理,建立了一种用ICP-OES测量复杂基体中多种金属元素的分析方法。将高温热解得到的磷酸铁锂回料进行高温下的酸消解,然后在ICP-OES中对不同的观测位进行比较。将得到的数据进行测量系统分析,通过计算精度/容差(%P/T)评估最佳的检验能力组合。经过对比,发现270℃的高温消解更利于金属异物的充分溶出,Al(径向)、Na(径向)、Ni(径向)、Mn(径向)、Cr(轴向)、Zn(径向)的ICP-OES观测方位组合能更准确、稳定地分析复杂基体的金属杂质元素组分。该分析方法简单、高效、计算量小,便于快速评估检验能力。在利用ICP-OES进行复杂基体的金属异物分析方面,此方法具有很好的借鉴意义。

ICP-OES法测定铁铬液流电解液中17种杂质元素

应用电感耦合等离子体原子发射光谱(ICP-OES)法对铁铬液流电解液中的杂质元素Ca、Mg、Na、K、Cu、Zn、Ni、Mn、Sn、Co、A1、Pb、Cd、As、Sb、S、Mo进行同时测定。通过对电感耦合等离子体原子发射光谱仪分析参数的优化。对影响分析结果准确度的因素进行校正,方法的准确度得到提高。应用本方法测定铁铬液流电解液中的杂质元素Ca、Mg、Na、K、Cu、Zn、Ni、Mn、Sn、Co、A1、Pb、Cd、As、Sb、S、Mo,加标回收率为81.1%~108.6%,相对标准偏差为0.26%~4.67%。

ICP-OES和ICP-MS测定川芎中20种元素的含量

以微波消解为主要前处理方式,采用电感耦合等离子体发射光谱法(ICP-OES)和电感耦合等离子体质谱法(ICP-MS)测定川芎中20种元素的含量,对两种方法的仪器条件和不同区域川芎元素含量影响因素进行研究。电感耦合等离子体发射光谱法测定(钾、钙、钠、镁、铝、铁)的检出限为0.001mg/L~0.023 mg/L;电感耦合等离子体质谱法测定(铅、镍、镉、铬、砷、锡、硒、锶、锑、钡、锰、锌、铜)的检出限为0.001568μg/L~0.4625μg/L。两种方法线性都非常好,相关系数均大于0.999。两种方法能够高效、准确地测定川芎中的元素含量。川芎中含量较高的钾、钙、钠、镁、铝、铁元素不同区域有一定差别,其余各种元素含量差别不大。测量发现实验区域川芎干样品中,微量元素锶含量较高,平均含量达到29.2 mg/kg。锶具有防止动脉硬化,防止血栓形成的功能。