【摘要】 矿石表面成像技术通过高精度分析元素分布和形貌，揭示矿石的组成、结构及潜在价值，因而在地质勘探、矿物加工和环境评估等领域中具有重要作用。现有的矿石表面成像技术，如X射线荧光光谱(XRF)、电子探针微区分析(EPMA)和扫描电子显微镜-能谱分析(SEM-EDS)等通常受到成像面积、轻元素盲区和高成本等因素的制约，因此，亟需开发一种快速大面积成像技术实现矿石表面的高精度成像。激光诱导击穿光谱(LIBS)技术因其具有能够检测低原子序数的元素，支持多元素同时检测，速度快，并能快速实现大面积成像等优点已经成为矿石表面元素成像技术的研究热点，目前的LIBS成像相关研究通过硬件升级，如kHz激光系统，激光扩束镜，高倍率聚焦物镜和高精度XYZ电机平台等提升了成像分辨率，但也显著地提高了设备成本、维护复杂度和技术门槛，引入的附加光学组件也可能降低系统的稳定性。因此，在有限的条件下，如何快速便捷地提高成像分辨率有待进一步研究。采用LIBS技术，通过热传导理论计算黄铁矿的烧蚀阈值和烧蚀坑几何尺寸，研究了透镜束腰半径与激光光斑尺寸的关系，在确保相邻烧蚀坑之间无相互干扰的情况下，确定了LIBS成像兼顾分辨率与烧蚀稳定性下的最优扫描步长。为验证理论计算的可靠性，在不同步长下(150、 200和300μm)进行激光烧蚀来观察黄铁矿表面的烧蚀坑之间的影响，结果表明实验测得的烧蚀坑尺寸与理论计算值相对误差为0.35%,验证了模型的适用性。实现了黄铁矿表面不同元素分布的成像。为进一步提高LIBS成像分辨率，采用自适应阈值平稳小波去噪，全谱归一化、双三次插值等数据处理方法提高其成像分辨率。结果表明，黄铁矿中Mg、 Si、 Al和Fe的元素分布的LIBS成像结果与扫描电子显微镜-能谱(SEM-EDS)获得的结果具有良好的一致性，进一步凸显了LIBS在矿石二维空间成像中的重要应用潜力。更多还原

【Abstract】 Ore surface imaging technology plays a crucial role in geological exploration, mineral processing, and environmental assessment by revealing elemental distributions, morphology, composition, structure, and potential value through high-precision analysis. However, conventional ore surface imaging techniques such as X-ray fluorescence spectroscopy(XRF), electron probe microanalysis(EPMA), and scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS) are generally constrained by limitations in imaging area, blind zones for light elements, and high operational costs. Consequently, there is an urgent need to develop a rapid large-area imaging technology for high-precision ore surface characterization. Laser-Induced Breakdown Spectroscopy(LIBS) has emerged as a research hotspot in elemental imaging due to its unique advantages: the capability to detect low atomic number elements, simultaneous multi-element analysis, rapid operation, and large-area imaging potential. While recent LIBS imaging studies have improved spatial resolution through hardware upgrades, these advancements significantly increase equipment costs, maintenance complexity, and technical barriers. Such hardware upgrades include kHz laser systems, laser beam expanders, high-magnification focusing objectives, and high-precision XYZ motorized stages, which can substantially improve imaging resolution. Additionally, the introduced auxiliary optical components may compromise system stability. Therefore, under practical constraints, further research is required to achieve convenient and cost-effective resolution enhancement. In this study, LIBS technology was employed to investigate pyrite surface elemental distribution. The ablation threshold and crater geometry of pyrite were calculated based on thermal conduction theory, while the relationship between lens beam waist radius and laser spot size was analyzed to determine optimal scanning step lengths. To verify the reliability of the theoretical calculation, laser ablation experiments were carried out on pyrite surfaces with different step lengths(150, 200, and 300 μm) to examine the interaction between adjacent craters. The results indicated that the relative error between the experimentally measured crater size and the theoretical value was 0.35%, confirming the applicability of the model. To enhance imaging resolution, data processing methods including adaptive threshold stationary wavelet denoising, full-spectrum normalization, and bicubic interpolation were implemented. Elemental distribution imaging of pyrite surfaces was successfully achieved. Results demonstrate strong consistency between LIBS imaging outcomes(Mg, Si, Al, and Fe distributions) and SEM-EDS analyses.更多还原