Fahad Muhammad, Ali Sajjad, Shah Khizar Hussain, Shahzad Asim, Abrar Muhammad
Appl Opt. 2019 Sep 20;58(27):7588-7596. doi: 10.1364/AO.58.007588.
Bauxite is a primary ore of aluminum. Precise information about bauxite mineralogical composition is challenging and crucial for efficient aluminum extraction and for the determination of its appropriateness for different industrial applications. For the qualitative and quantitative analysis of bauxite ore, we performed laser-induced breakdown spectroscopy (LIBS) in conjunction with x-ray diffraction (XRD), x-ray fluorescence spectroscopy (XRF), scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR). Analysis of the acquired optical emission spectrum revealed the presence of Si, Al, Fe, K, Ti, Ca, Mg, Na, Cr, and Sr. The plasma temperature and electron number density values estimated using Boltzmann plot and Stark-broadening line profile methods were 5600 K and 7.65×10 cm, respectively. In the present study we show that a calibration-free LIBS method presents a powerful solution, enabling quantitative analysis of multi-element bauxite ore better than traditional analytical techniques. The bauxite quantification obtained using CF-LIBS under the assumption of local thermodynamic equilibrium and optically thin plasma was Si=47.31%, Al=31.90%, Fe=16.54%, K=2.45%, Ti=1.64%, and Ca=0.16%, and its comparison with the outcome from XRD, XRF, SEM-EDS, and FTIR not only assisted but potentially enhanced the mineralogical composition understanding of bauxite ore in the present study.
铝土矿是铝的主要矿石。关于铝土矿矿物成分的精确信息具有挑战性，但对于高效提取铝以及确定其是否适合不同工业应用至关重要。为了对铝土矿进行定性和定量分析，我们结合X射线衍射（XRD）、X射线荧光光谱（XRF）、扫描电子显微镜与能量色散X射线光谱联用（SEM-EDS）以及傅里叶变换红外光谱（FTIR）进行了激光诱导击穿光谱（LIBS）分析。对采集到的发射光谱进行分析后发现了硅、铝、铁、钾、钛、钙、镁、钠、铬和锶的存在。使用玻尔兹曼图和斯塔克展宽线轮廓法估算的等离子体温度和电子数密度值分别为5600 K和7.65×10 cm。在本研究中，我们表明无校准LIBS方法是一种强大的解决方案，能够比传统分析技术更好地对多元素铝土矿进行定量分析。在局部热力学平衡和光学薄等离子体假设下，使用CF-LIBS获得的铝土矿定量结果为：硅=47.31%，铝=31.90%，铁=16.54%，钾=2.45%，钛=1.64%，钙=0.16%，并且将其与XRD、XRF、SEM-EDS和FTIR的结果进行比较，不仅有助于而且可能增强了本研究中对铝土矿矿物成分的理解。
