基于激光诱导击穿光谱的水泥品质在线检测研究

发布时间：2018-07-17 19:31

【摘要】：长期以来,水泥作为重要的胶凝材料,广泛用于民用、工业、农业、水利、交通和国防等工程。使用合格水泥是保证工程结构质量和生命财产安全的必要前提,水泥品质检验是水泥生产过程中的一个重要环节,在整个水泥生产过程中原料配比是决定水泥品质合格与否和成本高低的关键。及时掌握入窑水泥生料品质尤其是各种主量元素氧化物的含量,就能通过调整各原料皮带秤速率达到原料配比的最优化,从而提高入窑合格率,保证水泥产品质量。然而,目前我国大多数水泥厂所采用的水泥品质分析方法主要局限于人工化验、X射线荧光法(X-Ray Fluorescence,XRF)等,操作繁琐且耗时长,无法及时反馈水泥生产中生料品质,甚至有辐射危害,难以保障现代水泥工业的时效性和安全性。因此,水泥行业在满足精度要求的同时,迫切需要发展一种更加快速的水泥品质在线检测方法。激光诱导击穿光谱(Laser-Induced Breakdown Spectroscopy,LIBS)是一种新兴的激光烧蚀光谱分析技术,它利用高功率脉冲激光器与物质相互作用产生荧光等离子体,并采用光学系统对荧光等离子体收集,最后依据等离子体光谱特性及元素特征发射谱线实现对样品的定性与定量分析。该技术因具有可多元素同时分析、无需样品预处理、分析速度快、安全无辐射等优势,是一种非常有潜力的水泥品质在线测量方法。本文首先客观地描述了水泥行业的发展现状以及目前水泥行业的检测方法;然后对LIBS技术的发展现状、基本原理和技术特点进行了介绍;接着对基于LIBS技术的水泥品质在线检测进行了研究,验证了该技术应用于水泥品质检测的可行性;最后研制了基于LIBS技术的水泥品质在线检测设备。论文主要完成了以下工作:1.发展了为激光诱导击穿光谱检测提供连续均匀粉末样品的气动取送样技术,具有气路稳压、油水过滤、管道反吹、气粉浓度调节等功能,解决了在线取送样中存在的堵灰、板结、不连续、不均匀、光学系统易受粉尘污染等问题,同时免去了传统人工取样和样品制备过程,为实现水泥生料品质的在线激光检测提供了必要条件;2.提出了基于支持向量机光谱数据处理的定量分析方法,构建了有效的数据预处理方法,对满足LTE态的等离子体进行了筛选,对元素特征谱线做了全谱归一化以及二次筛选,最后使用Matlab工具包中的SVM函数对水泥生料中的CaO、SiO2、Al2O3、Fe2O3和MgO五种氧化物进行了定标建模,定标模型对五种氧化物测量的平均绝对误差分别为 0.22%,0.38%,0.18%,0.022%和 0.036%。3.经过光、机、电、气一体化系统集成,研制出水泥生料品质激光在线检测成套装备,装备由气动取送样装置、激光检测装置、信号采集与控制模块、远传模块和清洁装置等组成,能够实现对水泥生料氧化物含量及三率值的精确测量。工业现场测试结果证明,水泥生料氧化物测量精度:Al2O3(0.18%)、CaO(0.22%)、Fe2O3(0.022%)、MgO(0.036%)、SiO2(0.38%);三率值测量精度:KH(0.07)、SM(0.07)、IM(0.07);测量用时:1/3/5/10分钟可选,维护周期:60天。
[Abstract]:Cement, as an important cementitious material, is widely used in civil, industrial, agricultural, water conservancy, transportation and national defense projects for a long time. The use of qualified cement is a necessary prerequisite for ensuring the quality of engineering structures and the safety of life and property. The quality inspection of cement is an important link in the process of cement production, and the raw materials are matched in the whole process of cement production. It is the key to determine whether the quality of cement is qualified or not. To master the quality of the raw material of the kiln in time, especially the content of various main element oxides, can be optimized by adjusting the belt scale rate of each material, thus improving the qualified rate of the kiln and guaranteeing the quality of the cement products. However, most of our country is now able to guarantee the quality of the cement. The cement quality analysis method used in cement plant is mainly limited to artificial testing, X ray fluorescence (X-Ray Fluorescence, XRF) and so on. It is complicated and time-consuming. It can not feed back the quality of raw material in cement production in time and even have radiation hazards, so it is difficult to ensure the timeliness and safety of modern cement industry. Therefore, the cement industry meets the accuracy of the cement industry. At the same time, it is urgent to develop a more rapid on-line detection method for cement quality. The laser induced breakdown spectroscopy (Laser-Induced Breakdown Spectroscopy, LIBS) is a new laser ablation spectrum analysis technique. It uses high power pulse laser to produce fluorescent plasma with the interaction of material, and uses optical system. Based on the characteristics of the plasma spectrum and the characteristic emission line of the element, the qualitative and quantitative analysis of the samples is realized based on the spectral characteristics of the plasma and the characteristic emission lines of the elements. The technology is a very potential on-line measurement method for cement quality because of the advantages of simultaneous analysis of multi elements, no sample pretreatment, fast analysis, safety and no radiation. This paper first objectively describes the development status of cement industry and the testing methods of cement industry at present, and then introduces the development status, basic principle and technical characteristics of LIBS technology, and then studies the on-line testing of cement quality based on LIBS technology, and proves the feasibility of applying this technology to cement quality testing. Finally, the on-line testing equipment for cement quality based on LIBS technology has been developed. The following work has been completed in this paper: 1. it has developed a pneumatic sampling technique for providing continuous uniform powder samples for laser induced breakdown spectrum detection, which has the functions of gas circuit pressure, oil and water filtration, pipeline back blowing, gas powder concentration adjustment and so on. The existing problems of dust, slab, discontinuous, uneven, optical system are easily contaminated by dust pollution and so on. At the same time, the traditional artificial sampling and sample preparation process are avoided, and the necessary conditions are provided for the on-line laser detection of the quality of cement raw material. 2. a quantitative analysis method based on the spectral data processing of support vector machine is proposed, and the effective method is constructed. The data preprocessing method is used to screen the plasma which satisfies the LTE state. The element characteristic spectral lines are normalized by full spectral normalization and two screening. Finally, using the SVM function in the Matlab toolkit, the calibration modeling of five oxides of CaO, SiO2, Al2O3, Fe2O3 and MgO in cement raw material is modeled. The calibration model is measured for five oxides. The mean absolute error is 0.22%, 0.38%, 0.18%, 0.022% and 0.036%.3., which are integrated by the integrated system of light, machine, electricity and gas. We have developed a complete set of laser on-line testing equipment for the quality of cement raw material. The equipment consists of the pneumatic sampling device, the laser detection device, the signal acquisition and control module, the remote transmission module and the cleaning device, which can realize the water to the water. Accurate measurement of oxide content and three rate of mud raw material. Industrial field test results show that the precision of oxide measurement for cement raw material: Al2O3 (0.18%), CaO (0.22%), Fe2O3 (0.022%), MgO (0.036%), SiO2 (0.38%); three rate measurement accuracy: KH (0.07), SM (0.07), IM (0.07); measurement time: 1/3/5/10 minutes, maintenance cycle: 60 days.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ172.66

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