激光诱导击穿光谱用于水泥质量分析研究

发布时间：2018-04-04 19:46

本文选题：激光诱导击穿光谱　切入点：等离子体　出处：《山西大学》2015年硕士论文

【摘要】：水泥质量的优劣直接影响到建筑工程的安全性,使用质量合格的水泥材料是保证工程结构质量的必要前提。水泥质量检验是水泥生产中的一个重要的环节,加强水泥质量的检验工作是保障水泥产品质量的必要前提。传统的水泥检测方法存在耗时长、操作繁琐、有辐射等局限,不能及时反馈水泥生产过程中的原料配比,无法满足现代水泥工业的时效性,迫切需要发展新的水泥质量检测技术。本文主要对激光诱导击穿光谱用于水泥质量检测进行了理论分析和实验研究,验证了该技术应用于水泥质量检测的可行性,同时研制了基于激光诱导击穿光谱技术的水泥质量检测设备。论文首先介绍了激光诱导等离子体的产生机制,论述了激光诱导击穿光谱定量分析原理及等离子体参数测量原理。然后,针对目前等离子体温度测量中某些元素不适于用Boltzmann平面法,及常用的Boltzmann平面法和双线法的测量精度较差的问题,提出结合Boltzmann-Maxwell分布和Saha-Eggert公式来提高等离子温度的测量精度；针对计算等离子体电子密度时谱线线宽不便测量的问题,利用高斯公式的面积与峰值关系建立了谱线线宽的简便算法；建立了基于Mcwhiter准则的等离子体局部热平衡LTE态的判定方法,为定量分析提供了有效光谱数据。接着,研制了基于激光诱导击穿光谱的水泥质量检测设备,介绍了其结构、光学系统、样品室等设计原理。利用该设备对水泥生熟料中主量成分及熟料率值进行了工业现场测试和分析,在定标建模过程中,评估了不同种类的定标样品对定量分析精度的影响,发现为了获得更高的测量精度,应该选用与被测样品同种类的样品进行单独定标；为了消除设备运行过程中因激光能量衰减等因素而导致测量误差的增大,提出一种快速线性校正方法,从而简化了设备的校正过程,延长了标定周期。实验结果表明,该LIBS设备对水泥生熟料中CaO、SiO2、Al2O3、Fe2O3测量的平均绝对误差分别为0.46%、0.25%、0.13%、0.05%,对水泥熟料率值KH、SM、IM测量的平均绝对误差分别为0.02、0.05和0.04,满足国家标准要求。最后,对全文进行了总结,并对激光诱导击穿光谱应用于水泥质量在线分析的进一步研究工作提出了展望。本文的创新之处在于：1.结合Boltzmann-Maxwell分布和Saha-Eggert公式,提出了提高等离子体温度测量精度的新方法；2.建立了基于Mcwhiter准则的等离子体局部热平衡LTE态的判定方法,为定量分析提供了有效光谱数据；3.提出了一种简便的线性校正方法,简化了LIBS设备的校正过程,延长了标定周期。
[Abstract]:The quality of cement directly affects the safety of construction projects, and the use of qualified cement materials is a necessary prerequisite to ensure the quality of engineering structures.Cement quality inspection is an important link in cement production.The traditional cement detection method has the limitation of long time consuming, complicated operation, radiation and so on. It can not feedback the raw material ratio in the cement production process in time, and can not satisfy the timeliness of the modern cement industry.It is urgent to develop new cement quality detection technology.In this paper, the theoretical analysis and experimental study of laser induced breakdown spectrum used in cement quality detection are carried out, and the feasibility of applying this technology to cement quality detection is verified.At the same time, a cement quality testing equipment based on laser induced breakdown spectroscopy is developed.Firstly, the mechanism of laser-induced plasma is introduced, the principle of laser induced breakdown spectrum quantitative analysis and the principle of plasma parameter measurement are discussed.Then, aiming at the problem that some elements in plasma temperature measurement are not suitable for Boltzmann plane method, and the measurement accuracy of Boltzmann plane method and two-line method are poor, a new method, Boltzmann-Maxwell distribution and Saha-Eggert formula, is proposed to improve the accuracy of plasma temperature measurement.In order to solve the problem of inconvenient measurement of line width when calculating plasma electron density, a simple algorithm of line width is established by using the relationship between area and peak value of Gao Si's formula.A method for determining the local thermal equilibrium LTE states of plasma based on Mcwhiter criterion is established, which provides effective spectral data for quantitative analysis.Then, the cement quality detection equipment based on laser induced breakdown spectrum is developed, and the design principle of its structure, optical system and sample chamber is introduced.The industrial field test and analysis of the principal component and clinker rate value of cement raw clinker were carried out by using this equipment. In the process of calibration modeling, the influence of different kinds of calibration samples on the quantitative analysis accuracy was evaluated.It is found that in order to obtain higher measurement accuracy, the same kind of sample should be selected to be calibrated separately, and in order to eliminate the increase of measurement error caused by laser energy attenuation and other factors during the operation of the equipment,A fast linear correction method is proposed, which simplifies the calibration process and prolongs the calibration period.Finally, the paper summarizes the whole paper, and puts forward the prospect of further research on the application of laser induced breakdown spectroscopy in the on-line analysis of cement quality.The innovation of this paper is that of 1: 1.Based on Boltzmann-Maxwell distribution and Saha-Eggert formula, a new method to improve the accuracy of plasma temperature measurement is proposed.A method for determining the local thermal equilibrium LTE states of plasma based on Mcwhiter criterion is established, which provides effective spectral data for quantitative analysis.A simple linear correction method is proposed, which simplifies the calibration process of LIBS equipment and prolongs the calibration period.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.66;TN249

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