Evaluation of Magnetic Separation Efficiency on a Cassiterite-Bearing Skarn Ore by Means of Integrative SEM-Based Image and XRF–XRD Data Analysis

Abstract

Image analysis data obtained from scanning electron microscopy provided data for a detailed evaluation of the separation efficiency for various processes involving the beneficiation of particulate materials. A dry magnetic separation by a drum type magnetic separator served as a case study to visualize effects of processing of a skarn ore with a high content of cassiterite as ore mineral (~4 wt%). For this material, iron oxides and silicates are the main gangue mineral groups. Based on the obtained data, partition curves were generated with the help of local regression. From the partition curves, the separation efficiency was evaluated and the relevant particle properties deduced. A detailed analysis of the bias of the quantitative mineralogical data is presented. This bias was monitored and further analyzed in detail. Thorough analysis of feed and products of magnetic separation enabled identification of the most important factors that control losses of cassiterite to the magnetic product, namely the association with iron oxides and particle sizes below ~40 µm. The introduced methodology is a general approach applicable for the optimization of different separation processes and is not limited to the presented case study.

Optimization of Microwave Reductive Roasting Process of Bauxite Residue

“…The influence of microwave energy on the sample, the effect of irradiation time, and the addition of carbon source to BR (C/BR ratio) were the parameters investigated to find the optimized combination to convert iron oxides into metallic iron, according to the sequence of Fe 2 O 3 →Fe 3 O 4 →FeO→Fe [31,37,38].…”

Multiscale Tomographic Analysis for Micron-Sized Particulate Samples

“…To avoid motion artifacts and to ensure the spatial homogeneity of the particles in a sample volume for optimal image segmentation results, the particles must be immobilized. Conventional methods of particle embedding in epoxy-based resins, as used in the preparation of polished sections, e.g., multidimensional particle analysis using Mineral Liberation Analysis (MLA) (an example given by Buchmann et al, 2018), are not suitable here due to the long curing times. Therefore, we have embedded the particles in a histological wax that is normally used for biological sample preparation.…”

Evaluation of Recyclability of a WEEE Slag by Means of Integrative X-Ray Computer Tomography and SEM-Based Image Analysis

“…SEM-based mineralogy (MLA) is a two-dimensional image analysis method based on scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy [9,10]. It is proven to be a practical method for multidimensional characterization of various phases [11][12][13]. Using MLA allows for an integrated analysis of shape, size, and distribution of various phases within a specimen which can be a sample block, thin section, or a grain mount.…”

“…XCT enables a non-destructive three-dimensional characterization of specimens. As it is based on the X-ray attenuation of the volume elements (voxel), which is a function of the materials' average atomic number, wavelength, material density, and path length, voxels can have different chemical composition but similar attenuation coefficients [12]. Studying multiphase materials such as ores and slags can, thus, be challenging.…”