自由定标激光诱导击穿光谱技术在铁矿石酸度分析中的应用

发布时间：2018-02-24 18:29

本文关键词： 激光诱导击穿光谱定量分析自由定标二分搜索法铁矿石　出处：《西北大学》2017年硕士论文　论文类型：学位论文

【摘要】：铁矿石是钢铁工业必需的基础原材料,而铁矿石酸度是影响钢铁冶炼产量的重要因素,因此急需建立一种实时在线检测铁矿石酸度的新技术和方法。激光诱导击穿光谱(Laser-induced breakdown spectroscopy,LIBS)是一项新兴的光谱分析技术,具有原位、很少或不需要样品制备和无损等优势,使其在冶金领域得到广泛的应用。自由定标方法(Calibration-free LIBS,CF-LIBS)无需标样定标,避免了基体效应,更适合于现场在线分析,但定量准确度不高。本文从提高铁矿石酸度分析准确性的实际问题出发,分析影响CF-LIBS定量准确性的因素,建立了铁矿石中Ca/Si比例及各自含量的定量分析方法。该研究提高CF-LIBS定量分析结果的可靠性,为现场在线分析铁矿石酸度提供新方法和技术支持,本文共分为四章,主要研究内容如下:首先,基于相似基体的不同样本在相同条件下灼烧等离子体温度相同的假设,采用CF-LIBS结合BSA对铁矿石酸度进行分析。首先对分析谱线强度进行内参考线自吸收校正,并使用校正后的分析线构建Boltzmann图,利用图中Ca I和Si I截距关系结合Saha方程获得Ca/Si摩尔比率,引入一个标准样品结合BSA确定最佳等离子体温度,将此温度用于未知样品的酸度分析。结果表明,未知样品计算得到的酸度接近真实值。所提出的方法可以有效分析铁矿石的酸度,同时可为铁矿石实时在线的筛选和工业质量控制提供参考。其次,采用分别优化Ca I和Si I的延迟时间,同时对Ca I和Si I谱线进行自吸收校正,为消除仪器的不确定性,采用OI进行谱线归一化校正,依据原子发射光谱定量原理结合Saha方程计算得到Ca和Si元素的数值浓度,从而计算出铁矿石酸度,结果表明,相比传统定量分析方法,该方法准确性有了很大的提高。因此该方法对于铁矿石酸度分析是一种有效和可靠的方法。最后,采用CF-LIBS结合标准加入法对铁矿石的酸度进行定量分析,首先对分析谱线进行自吸收校正,之后依据实验参数F为定值的原理,得到Ca和Si含量。结果分析表明,该方法在理论和实际实验中均是可行的,该方法引入内参考元素避免了CF-LIBS全元素归一的限制,操作简单快速,定量结果准确,增强了实用性,使其满足现场实验的要求。
[Abstract]:Iron ore is the basic raw material necessary for the iron and steel industry, and the acidity of iron ore is an important factor affecting the production of iron and steel smelting. Therefore, it is urgent to establish a new technique and method for real-time and on-line detection of iron ore acidity. Laser-induced breakdown spectroscopy (LIBSs) is a new spectral analysis technique, which has the advantages of in situ, little or no sample preparation and nondestructive. The free calibration method Calibration-free Libbs (CF-LIBS) can avoid the matrix effect and is more suitable for on-line field analysis. However, the quantitative accuracy is not high. This paper analyzes the factors that affect the accuracy of CF-LIBS quantitative analysis based on the practical problems of improving the accuracy of iron ore acidity analysis. A quantitative analysis method for the proportion and content of Ca/Si in iron ore is established. The research improves the reliability of quantitative analysis results of CF-LIBS and provides a new method and technical support for on-line analysis of iron ore acidity. This paper is divided into four chapters. The main research contents are as follows: firstly, based on the assumption that different samples of similar matrix have the same plasma temperature under the same conditions, The acidity of iron ore is analyzed by CF-LIBS and BSA. Firstly, the intensity of the analytical line is corrected by internal reference line self-absorption, and the Boltzmann diagram is constructed by using the corrected analysis line. The molar ratio of Ca/Si was obtained by combining the Ca I and Si intercept relation with Saha equation. A standard sample combined with BSA was introduced to determine the optimum plasma temperature, and the temperature was applied to the acidity analysis of unknown samples. The acidity calculated from the unknown sample is close to the real value. The proposed method can effectively analyze the acidity of iron ore, at the same time, it can provide a reference for the real-time on-line screening and industrial quality control of iron ore. The delay time of Ca I and Si is optimized, and the self-absorption correction of Ca I and Si is carried out at the same time. In order to eliminate the uncertainty of the instrument, Oi is used to normalize the spectral line. According to the quantitative principle of atomic emission spectrum and Saha equation, the numerical concentration of Ca and Si is calculated, and the acidity of iron ore is calculated. The results show that compared with the traditional quantitative analysis method, The accuracy of this method has been greatly improved. Therefore, this method is an effective and reliable method for acidity analysis of iron ore. Finally, the acidity of iron ore is quantitatively analyzed by CF-LIBS combined with standard addition method. The self-absorption correction of the analytical spectral line is carried out at first, and then the Ca and Si contents are obtained according to the principle that the experimental parameter F is fixed. The results show that the method is feasible in both theory and practice. The method introduces internal reference elements to avoid the limitation of CF-LIBS full element homogenization, is simple and fast, accurate quantitative results, enhances the practicability, and makes it meet the requirements of field experiments.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;TF041

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