Abstract
An effective correction method for stereological bias is required because of the importance of accurate assessment of mineral liberation of ore particles. Stereological bias is error caused by the estimation of a three-dimensional liberation state based on two-dimensional sectional measurements. Recent studies have proposed a stereological correction method based on sectional particle texture analysis, which employs numerical particle models. However, the applicability of this method to unfamiliar particle systems, with different shape and texture characteristics from the numerical particle model, has not been thoroughly investigated. In this study, the viability of the method for examination of the internal structure and shape of unfamiliar particles, was assessed using four types of particle systems, based on combinations of two types of internal structures (Boolean and Voronoi) and two types of particle shapes (spherical and irregular). Seven different texture analysis indices were utilized for composition distribution correction with regard to each of the four types of particle systems. The results suggested that a model based on the angular second moment and/or entropy, employed by the spatial gray level dependence method, showed the greatest viability for assessment of unfamiliar particle internal structure and/or shape.
Highlights
In mineral processing, comminution mainly aims to achieve mineral liberation, freeing valuable minerals from gangue to enhance the efficiency of the subsequent selection and, the total efficiency
We found that the gray level run length method, Fourier power spectrum method, and gray level histogram method were not suitable for incorporation in the proposed stereological correction method, as they are better suited analyze stripe pattern, periodical pattern, and color tone, respectively, which are not common in the ore texture
The difference between the 2D and 3D curves due to stereological bias was considerably reduced by all the correction methods
Summary
Comminution mainly aims to achieve mineral liberation, freeing valuable minerals from gangue to enhance the efficiency of the subsequent selection and, the total efficiency. Mineral liberation states are assessed through two-dimensional (2D) measurements of ore particle sections that are resin-mounted, cross-sectioned, and polished They are typically measured using automated analyzing systems based on scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), such as a mineral liberation analyzer (MLA) [1,2] quantitative evaluation of minerals by scanning electron microscopy [3], and a TESCAN integrated mineral analyzer [4]. Several means have been employed to directly measure the 3D liberation state without stereological bias, such as X-ray computed tomography (CT) [5,6,7,8,9,10], serial sectioning [11,12,13], and dense medium separation using heavy liquids [14] or magnetic fluid [15] These all have disadvantages for Minerals 2017, 7, 222; doi:10.3390/min7110222 www.mdpi.com/journal/minerals
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