基于LIBS结合机器学习的滑石等级识别研究

Study on Talc Grade Identification Based on LIBS Combined with Machine Learning

  • 摘要: 滑石作为一种高值工业矿物,其等级的精准划分直接影响下游工业产品质量与附加值。当前滑石分类多依赖人工目检或传统光学分选技术,主观性强、效率低及误判率高。X射线荧光光谱(XRF)、近红外光谱技术(NIRS)、中子活化技术(NAA)等在线检测技术在特定场景下具有一定应用优势,但存在响应滞后、检测成本高等不足,难以满足现代化生产中快速检测需求。因此,滑石品质等级识别亟需构建准确、高效的在线分类技术。本文通过搭建在线激光诱导击穿光谱(LIBS)分析装置,实现对传送带上移动滑石样品品质的快速检测。针对滑石样品形状不规则导致的LIBS光谱波动,通过特征元素光谱强度相对标准偏差(RSD)识别焦点处的有效数据,减少了因样品表面不规则所导致的光谱数据波动。选取Al、Ca、Mg、Fe、Na及Si等关键元素的特征谱线,基于主成分分析(PCA)降维后,分别构建支持向量机(SVM)、K近邻算法(KNN)及随机森林(RF)三种机器学习分类模型。结果分析表明,SVM分类模型在对测试集运算的准确度、精准度、召回率及 F1分数等四项指标上均最优,识别准确率为99.4%。通过LIBS技术与机器学习相结合的策略,为滑石矿等级的实时在线分类提供一种快速、准确的新方案,对工业滑石资源高效利用具有重要的实用价值。

     

    Abstract: As a high-value industrial mineral, the accurate classification of talc quality grades directly impacts the quality of downstream industrial products and the added value of resource utilization. Currently, traditional talc classification primarily relies on manual visual inspection or conventional optical sorting techniques, which suffer from strong subjectivity, low efficiency, and high misjudgment rates. Existing online detection technologies such as X-ray fluorescence spectroscopy (XRF), near-infrared spectroscopy (NIRS), and neutron activation analysis (NAA) exhibit certain application advantages in specific scenarios but are generally plagued by high equipment costs, response delays, and elevated detection expenses. These limitations render them inadequate to meet the demand for rapid online detection in modern production lines. Therefore, there is an urgent need to develop an accurate, efficient online classification technology for the precise identification of talc quality grades. Laser-induced breakdown spectroscopy (LIBS) technology, characterized by the elimination of complex sample pretreatment, remote operability, and rapid real-time online analysis capabilities, offers a novel and effective solution for talc classification. In this study, a self-designed online LIBS experimental setup was constructed to achieve rapid quality detection of talc samples moving on a conveyor belt. To address LIBS spectral fluctuations caused by the irregular shape of talc samples, effective spectral data at the detection focal point were screened using the relative standard deviation (RSD) of characteristic element spectral intensities, thereby reducing data variability induced by surface irregularities. Characteristic spectral lines of key elements (Al, Ca, Mg, Fe, Na, and Si) were selected and dimensionally reduced via Principal Component Analysis (PCA). Subsequently, three machine learning classification models—support vector machine (SVM), K-nearest neighbors (KNN), and random forest (RF)—were established based on the PCA-processed data. Comparative analysis of the results demonstrated that the SVM model outperformed the others across four key metrics: accuracy, precision, recall, and F1-score, achieving a classification accuracy of 99.4%. The kernel function mechanism of SVM effectively captures nonlinear features in spectral data. In conclusion, the integration of LIBS technology with PCA dimensionality reduction and SVM machine learning provides a rapid, high-accuracy technical scheme for the real-time online classification of talc grades. This approach holds significant practical application value in promoting the efficient utilization of industrial talc resources.

     

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