Laser-induced breakdown spectroscopy; X-ray fluorescence; Reflectance spectroscopy; Data fusion; Mineral interpretation; Partial least squares;INDUCED BREAKDOWN SPECTROSCOPY; QUANTITATIVE MINERALOGY; RAMAN-SPECTROSCOPY; WESTERN-AUSTRALIA; WAVELENGTH; DEPOSIT

This article is extension of the earlier work (Khajehzadeh et al., 2016), where quantitative mineralogical information of slurry samples was achieved using an on-stream LIES analyzer. Despite the great advances in the analytical methods and laser-based measurement techniques, the industrial developers are still demanding novel ideas enabling differentiation between minerals having similar elemental contents such as hematite and magnetite or silicon-bearing minerals such as quartz and other mixed silica minerals since they have different flotation properties. The available analytical techniques for LIES spectral analysis (including the earlier work of this research) could not distinguish between such minerals with identical elemental contents. This work at first presents data fusion of LIES and reflectance spectroscopy and then discusses the data fusion of reflectance spectroscopy and X-ray fluorescence (XRF) measurement techniques operating on the same slurry samples. The results will show that such data integrations enable on-stream and quantitative identification of slurry mineral contents specially for hematite, magnetite, quartz and ferrorichterite which are important minerals in iron ore beneficiation.

MATRIX CONVERSION; QUANTITATIVE-ANALYSIS; AQUEOUS-SOLUTIONS; METAL DETECTION; HEAVY-METALS; SPECTROMETRY; LIBS; MICROEXTRACTION; PLASMA; MEMBRANE

Laser-induced breakdown spectroscopy (LIBS) is a simple, fast, and direct technique for the elemental analysis of various samples. However, the practical application of this method in direct liquid analysis is limited due to its inherent disadvantages including surface ripples and extinction of emitted intensity. Applicable treatments of liquids always involve complicated procedures or additional instruments, which is disadvantageous to its analytical performance. In this study, we proposed a novel method for the LIBS analysis of liquid samples via a hydrogel-based solidification technique. In this new method, aqueous solution is directly poured into sodium polyacrylate resins. Owing to the high hydroscopicity of sodium polyacrylate resins, the resins quickly form a hydrogel and immediately solidify the liquid samples. After this, the LIBS analysis is directly performed. To estimate the analytical performance of this proposed method, calibration curves were established and limits of detection for Al, Cu, and Cr were obtained. The limits of detection (CODs) for the emission lines of Al(I) 308.21 nm, Cu(I) 324.75 nm, and Cr(I) 425.43 nm were 0.460 mu g mL(-1), 4.69 mu g mL(-1), and 4.44 mu g mL(-1), respectively. According to the obtained results, this proposed method demonstrates its better analytical performance in terms of CODs at the ppm level and requires shorter processing time as compared to other analytical methods based on the LIBS technique for liquid sample analysis. Especially, the short pretreatment of samples and simple auxiliary equipment make this hydrogel-based solidification method bring LIBS out of the laboratory for the direct analysis of environmental liquid samples. The feasibility and potential of this novel method have also been discussed for special analytical applications in slurry samples.