Mineral Liberation Analysis Research Articles

Preparation of high-purity magnetite from iron ore concentrate

In pursuit of environmental protection and green, low-carbon economic development, China has proposed the dual-carbon strategies of carbon peak and carbon neutrality. To achieve the dual-carbon goals, traditional steel metallurgical production processes are gradually shifting towards green and low-carbon hydrogen metallurgical processes. However, hydrogen metallurgical processes have strict requirements for raw materials and typically require the utilization of high-grade iron concentrates. The scarcity of high-grade iron ore in China severely constrains the development of hydrogen metallurgical processes. Therefore, this study proposes the utilization of ordinary magnetite concentrate to produce high-grade magnetite. Comprehensive analytical methods, including chemical analysis, X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) analysis, laser particle size testing, optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and mineral liberation analysis, were employed to elucidate the mineralogical characteristics of the iron concentrate. The analysis revealed that the iron concentrate had a total iron (TFe) grade of 65.56 %, with SiO2 and Al2O3 contents of 8.28 % and 0.38 %, respectively. Subsequently, a combined beneficiation process involving magnetic separation, flotation, and chemical leaching was conducted. Experimental results showed that a single magnetic separation obtained an iron concentrate grade of 67.52 % with an overall recovery of 86.18 %. Following magnetic separation, flotation was conducted to increase the concentrate grade. With one roughing and four cleaning flotation stages, a concentrate grade of 72.19 % and a 36.36 % overall recovery were achieved. A subsequent leaching operation after flotation yielded high-purity magnetite with a Fe grade of 72.30 % and an overall recovery of 35.68 %. The high-purity magnetite was confirmed to have a purity of up to 99.9 % based on chemical titration, XRD analysis, magnetic susceptibility measurement, and SEM analysis. Furthermore, detailed kinetics studies on leaching were conducted to elucidate the reaction mechanism, revealing an apparent activation energy of 25.70 kJ/mol. The successful implementation of this process will provide a benchmark for producing similar high-purity magnetite concentrates and contribute to China’s dual-carbon goals.

A novel vacuum roasting technology applied to the processing of mineral medicine pyritum: low heavy metal and environmentally friendly

Pyritum, a mineral medicine, has been widely used in orthopedics and traumatology in China for nearly 1500 years. Before its use as a drug, it must be air-roasted and vinegar-quenched to produce an effective compound, pyrrhotite (Fe7S8), while reducing harmful substances. However, this process is prone to generating toxic compounds such as sulfur dioxide (SO2) and arsenic trioxide (As2O3). Moreover, processed pyritum sold in China still exhibits significant issues with high levels of arsenic (As) and lead (Pb). This study proposes a green processing method for vacuum roasting pyritum. FactSage software was used to confirm that the vacuum environment facilitates the production of Fe7S8 while effectively preventing oxidation and simplifying the removal of As and Pb. The iron (Fe) content within the temperature range of 600–1000 °C increases from 27.96% to 62.41%. X-Ray Diffraction (XRD) and Mineral Liberation Analyzer (MLA) results indicate a significant transformation of the primary component, pyrite (FeS2), in pyritum into Fe7S8.The optimal processing conditions were determined to be vacuum roasting at 1000 °C for 60 min, resulting in a remarkable removal efficiency of 70.27% for Pb and the complete elimination of As. It can be concluded that vacuum roasting pyritum is a simple, high-stability, environmentally friendly, and clean procedure.

Application of Multivariate Tromp Functions for Evaluating the Joint Impact of Particle Size, Shape and Wettability on the Separation of Ultrafine Particles via Flotation

Froth flotation predominantly separates particles according to their differences in wettability. However, other particle properties such as size, shape or density significantly influence the separation outcome as well. Froth flotation is most efficient for particles within a size range of about 20–200 μm, but challenges arise for very fine or coarse particles that are accompanied by low recoveries and poor selectivity. While the impact of particle size on the separation behavior in flotation is well known by now, the effect of particle shape is less studied and varies based on the investigated zone (suspension or froth) and separation apparatus used. Beyond these complexities, many particle properties are correlated, making it challenging to analyze the isolated impact of individual properties on the separation behavior. Therefore, a multidimensional perspective on the separation process, considering multiple particle properties, enhances the understanding of their collective influence. In this paper, the two-dimensional case is studied; i.e., a parametric modeling approach is applied to determine bivariate Tromp functions from scanning electron microscopy-based image data of the feed and the separated fractions. With these functions it is possible to characterize the separation behavior of particle systems. Using a model system of ultrafine (<10 μm) particles, consisting of either glass spheres or glass fragments with different wettability states as the floatable fraction and magnetite as the non-floatable fraction, allows for the investigation of the influence of descriptor vectors consisting of size, shape and wettability, on the separation. In this way, the present paper contributes to a better understanding of the complex interplay between certain descriptor vectors for the case of ultrafine particles. Furthermore, it demonstrates the benefits of using multivariate Tromp functions for evaluating separation processes and points out the limitations of SEM-based image measurements by means of mineral liberation analysis (MLA) for the studied particle size fraction.

A clean and green technology for iron extraction from refractory siderite ore via fluidization self-magnetization roasting

As a refractory iron resource, siderite has gained significant attention in the fields of mineral processing and metallurgical industry due to its abundant availability. However, its direct utilization in iron and steel production is often hindered by the presence of impurities, including silicates and carbonates, as well as the lower theoretical iron grade so it is necessary to increase iron and reduce impurities. To unlock the full potential of these abundant iron ore deposits, advanced processing techniques are imperative. In this work, a clean and green technology was proposed for extracting iron from siderite via fluidization self-magnetization roasting and magnetic separation. The mechanism of fluidization self-magnetization was investigated by thermodynamic analysis, X-ray diffraction (XRD), iron phase analysis, Mineral Liberation Analyzer (MLA), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS). The results show that concentrate with a Fe grade of 61.74% and Fe recovery of 81.78% could be obtained after treatment by fluidization self-magnetization roasting and magnetic separation. The analysis reveals the siderite eventually transformed into magnetite after fluidization self-magnetization roasting, with the saturation magnetization increasing from 0.91 A·m2·kg−1 to 7.92 A·m2·kg−1. In this process, many cracks were generated on the surface of the ore, which not only likely contributes to the self-magnetization roasting but also facilitates the individual dissociation of iron minerals from gangue minerals during the grinding process. Subsequently, iron minerals can be recovered through magnetic separation. The fluidization self-magnetization roasting technology demonstrates significant potential in achieving the green and clean utilization of siderite.

Evaluation of Ni-Cu Ore from Zapolyarnoe Based on Mineralogical and Physical Properties before and after Comminution

For the effective comminution and subsequent enrichment of mineral ores, comprehensive knowledge of their mineralogical and physical properties is required. Using an integrated methodology, this study evaluated samples of polymetallic Ni-Cu ore from Zapolyarnoe, Russia. Several analytical techniques were utilised, including optical microscopy, microindentation with Vickers geometry, the Point Load Test, and Mineral Liberation Analysis (MLA). The purpose of this study was to determine mineral associations, physical features, and enrichment during jaw crusher comminution. The acquired properties included the Point Load Strength Index, Vickers Hardness Number, and fracture toughness. The MLA method characterised seven fractions in terms of particle size distribution, degree of liberation, association, and modal mineralogy. Magnetite, pyrrhotite, pentlandite, and chalcopyrite were calculated in terms of wt% and their textural features. The enrichment of each ore phase in fractions with particle sizes smaller than 400 µm was determined. The influence of this enrichment was discovered to be correlated with various textural and structural parameters, such as intergrowth, grain size, and crack morphologies after indentations. In addition, the chromium content of magnetite contributed to an increase in the fracture toughness values. Despite the complexities involved, even limited samples of materials provide valuable insights into processing behaviour, emphasising the importance of considering mineralogical parameters in comminution studies.

A case study on the recovery of unevenly embedded particle size in high-carbon chalcopyrite using an alkyne-based thioester collector: Flotation processing and adsorption mechanism

The difference in chalcopyrite's primary ore-hosting rocks (dolomite and carbonaceous slate) in the Democratic Republic of the Congo results in an extremely uneven grain size distribution. Additionally, the presence of 2.21% organic carbon in the gangue impacts flotation efficiency. To address these challenges, ore properties were analyzed using the Mineral Liberation Analyzer (MLA), X-Ray Diffractometer (XRD), and microscopy. Flotation process was modified to incorporate a "middlings regrinding" processing, utilizing PDEC (an alkyne-based thioester collector, prop-2-yn-1-yl diethylcarbamodithioate) as the collector for experimental studies. Density Functional Theory (DFT) calculations elucidated the interaction mechanism of PDEC on chalcopyrite's surface. The MLA analysis indicates that chalcopyrite is mainly found in medium to fine grains, with the presence of fine-grained copper minerals smaller than 0.04mm accounting for 16.29% of the sample. This implies that these minerals require fine grinding for effective separation. Despite interference from organic carbon, PDEC demonstrates remarkable selectivity and efficiency in chalcopyrite flotation. By employing the "middlings regrinding" flotation method, a concentrate with a Cu content of 26.79% and a recovery of 87.88% was achieved, representing an increase of 0.17% in Cu grade and 4.09% in recovery rate compared to the conventional flotation process. DFT analysis demonstrates that the S 3p orbitals in carbon-sulfur double bond of PDEC and the C 2p orbitals in its acetylene group significantly affect its collection efficiency, engaging in hybridization with the Fe 3d orbitals on the surface of chalcopyrite, thereby facilitating a robust bonding interaction.

Enhancing Recovery of Ultra-Fine Magnetite from Low-Iron-Grade Cyanidation Tailings by Optimizing Flow Field Parameters of Low-Intensity Magnetic Separation (LIMS)

The characteristics of iron minerals in cyanidation tailings with a low iron grade were determined via chemical composition analysis, iron phase analysis, and mineral liberation analysis (MLA). The results showed that the cyanidation tailings contained 15.68% iron, mainly occurring in the form of magnetite (19.66%) and limonite (79.91%), in which 16.52% magnetite and 65.90% limonite particles were fully liberated. Most ultra-fine magnetite grains were adjacent and wrapped with limonite to form complex intergrowths, which resulted in low-efficiency magnetite recovery in low-intensity magnetic separation (LIMS) and adversely affected the downstream high-gradient magnetic separation (HGMS) process. Thus, in this work, the optimization of the flow field was proposed to enhance the separation of ultra-fine magnetite from the cyanidation tailings using pilot-scale LIMS separation, and the controllable parameters (including feed flow, separation gap, drum rotating speed, and solid weight) affecting ultra-fine magnetite capture were investigated. Under optimized conditions, a high-grade magnetite concentrate assaying 63.31% Fe with 86.46% magnetite recovery was produced, which, respectively, increased by 0.76% and 15.22%, compared with those obtained from industrial production. In addition, from the flow dynamics simulation, it was found that the magnetite particles in the −6 µm ultra-fine fraction were lost much more easily than those of coarser fractions due to the relatively enhanced hydrodynamic drag force acting on the particles compared with the magnetic force. However, this loss would be effectively reduced with the regulation and control of the flow field. The iron recoveries in the −16~+6 µm and −6 µm fractions of magnetite concentrate increased by 3.66% and 4.42%, respectively, under optimized hydrodynamic conditions. This research outcome provides a valuable reference for the economic and effective utilization of iron resources from such solid wastes.

Characterisation of rare earth element-bearing mineral phases present in South African coal ash using Mineral Liberation analysis

Critical raw materials, including rare earth elements (REE), are the cornerstone of modern technologies. Due to their unique properties, REE are in high demand, leading to the exploration and research of alternative sources. Coal combustion by-products, specifically coal ash, has been identified as a potential alternative source of REE, but more research is required. This study aimed to identify REE’s occurring in power station and laboratory-derived coal ash. Results from Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Mineral Liberation Analysis are presented herein, to gain insight into rare-earth-bearing minerals occurring in the ash samples.REEs were determined in both sets of ash samples at values higher than 600 parts per million (ppm) using ICP-MS. Critical REE occur in ranges from 203 to 406 ppm; uncritical REE from 179 to 256 ppm; and excessive REE ranging from 197 to 348 ppm in these samples. Laboratory-derived coal ash and power station-generated ash samples were prepared as polished blocks and coated for examination using a Mineral Liberation Analyser (MLA). A bright phase search mode was employed to detect rare earth-bearing mineral phases using the back-scattered electron detector (BSE).Energy dispersive spectroscopy (EDS) was used to determine elemental compositions in these phases.Four rare earth-bearing mineral phases were determined, namely: monazite-REE, xenotime-REE, Ce-REErium rich, and REE-silicate. The laboratory-derived ash samples had a greater proportion of liberated rare earth-bearing minerals, related to the lower proportion of aluminosilicate glassy phase, related to the low temperature ashing procedure.The detailed mineralogy provides insight into the design of REE extraction processes, targeting specific REE’s hosted in the various minerals. This will be documented in a future paper.

Occurrence state and distribution characteristics of tungsten in Dabaoshan tungsten-bearing goethite

The phase composition and elemental distribution of the tungsten-bearing goethite in Dabaoshan, Guangdong Province, China, were explored through various analytical methods, aiming to reveal the occurrence state and embedding characteristics of critical metal W in the ore. X-ray fluorescence analysis (XRF), powder X-ray diffraction (powder XRD), and scanning electron microscopy and energy dispersive spectroscopy (SEM–EDS) results show that the grade of critical metal W is 1.35%, and its main minerals are tungsten-bearing goethite and quartz. Micro-area XRD and mineral liberation analyzer (MLA) results indicate that ferrotungsten ore ((W,Fe)(O,OH)3), the tungsten-bearing phase, was mainly present in the form of stripped and banded goethite. The valuable element distribution in major minerals was also quantitatively determined. Moreover, a possible mechanism for the evolution and formation of tungsten-bearing goethite weathering was discussed, and a combined flowsheet of beneficiation–metallurgical separation was proposed to provide a theoretical basis for the high-efficient recovery of critical metal W from tungsten-bearing goethite.

Study on Process Mineralogy of the Combined Copper Oxide Ore in Tibet and Acid Leaching Behavior with Calcium Fluoride

The Yulong copper deposit in Tibet is a typical porphyry copper deposit, with about 30 million tons of copper oxide ore in the surface layer. However, more than 40% of the copper resources are in a combination state, resulting in an extraction efficiency of only 50% for copper via the hydrometallurgical process. In this study, the process mineralogy of the combined copper oxide ore was systematically investigated and a calcium fluoride-enhanced leaching process is proposed to increase the leaching efficiency of the combined copper ore. The process mineralogy of the combined copper oxide ore was analyzed using various testing techniques, including chemical analysis, X-ray diffraction, and a process mineralogy parameter testing system (Mineral Liberation Analysis). The results revealed that limonite accounted for 86.12% of the sample, and 63.51% of the copper resource existed in the form of combined copper oxide in limonite. However, it is difficult for the uniformly distributed combined copper oxide in limonite to sufficiently make contact with sulfuric acid, which is the leaching agent, resulting in low copper leaching efficiency. The enhanced leaching behavior of the combined copper oxide ores was also investigated, thereby determining effective and economical enhanced leaching conditions. Under optimal conditions, at a grinding fineness ratio of −0.074 mm (accounting for 85%), liquid-solid ratio of 4:1, sulfuric acid concentration of 50 g/L, temperature of 30 °C, CaF2 dosage of 1% of the ore mass, and leaching time of 4 h, the copper leaching efficiency increased to 60.57%, which was 7.34% higher than that of atmospheric pressure leaching. Finally, the enhanced leaching slag was analyzed using an electron probe microanalyzer. It indicated that fluorine ions can erode the combined copper oxide ore and facilitate the diffusion of hydrogen ions inside the limonite, thereby achieving a strengthening effect.

Selective extraction of rare earth elements and cobalt from iron residue containing rare earth using mechanical activation and reductive leaching method

NdFeB waste is an important rare earth secondary resource, which is usually treated by hydrochloric acid preferential method in traditional industrial process. Herein, leaching residue containing about 0.5–1 % rare earth elements (REEs) and a small amount of cobalt is generated as a by-product in the process. The leaching residue is mainly composed of iron oxide and generally sold to steelmaking plants, resulting in the waste of REEs and cobalt resource. An efficient recycling process is proposed for selectively extracting REEs and cobalt from the iron residue containing rare earth by mechanical activation and reductive leaching method based on mineral liberation analysis (MLA) and thermodynamic analysis. By analyzing the composition of the raw materials, magnetite and limonite are in an encapsulated state with rare earth minerals. REEs and cobalt are mainly present in the rare earth aluminate phase. To achieve deep extraction of REEs and cobalt, the first step is to change the insoluble phase of iron residue by mechanical activation method. During this process, the crystal structures of Fe2O3 and Fe3O4 in the iron residue containing rare earth are disrupted and transformed into amorphous states. During the reductive leaching process, part of the iron is converted into divalent. The iron in the leaching solution can be removed by hematite method and achieved phase reconstruction. Thus, REEs and cobalt can be extracted selectively from leaching residue of NdFeB waste.

Coal middling retreatment using high voltage pulses technique: selective liberation mechanism

ABSTRACT With combined efforts from the mineral liberation analyzer (MLA), elementary analysis and sulfur speciation analysis, this study expands upon coal fragmentation using high voltage pulse (HVP) by incorporating an understanding about deportment of specific minerals due to density behavior. Mineral characteristics showed that the minerlisation of middlings sample was predominantly banded, and pyrite was most of all associated with the mineral matter, to a lesser extent, with the organic matter. In addition, it was found that the pyritic sulfur attained a higher propensity for the heavy densities than the total sulfur, and the results were supported by speciation analysis. For Test 3, the total sulfur (0.86%) predominantly arose from organic sulfur due to the condensation of organic matter in the −1.3RD fraction, whereby the pyritic sulfur merely accounted for 25.80% of the total sulfur. It is concluded that the metalliferous grain-induced breakdown resulted in pulse selectivity between the middling particles. The improvement in coal middlings reprocessability (deashing and desulfuration) predominantly arose from the generation of cracks/microcracks. The results of this study have shown that the high voltage pulse (HVP) technique holds considerable promise for coal middlings reprocessing in comparison with the mechanical crushing method.

How do the occurrence patterns of potentially toxic elements (PTEs) control their release behaviours from Pb/Zn smelter contaminated soils?

Little information is available on the occurrence patterns of potentially toxic elements (PTEs) controlling their release behaviors, according to the results from leaching tests, multidisciplinary characterization and geochemical modeling. In this study, the occurrence characteristics of PTEs were dentified by combining Tessier results with X-ray photoelectron spectroscopy (XPS) and mineral liberation analyzer (MLA) and their main release mechanisms were elucidated based on geochemical modeling results from PHREEQC software. The results indicated that 0–17.69% of As, 0–27.90% of Pb and 0–82.17% of Zn were hosted in the non–reactive silicate minerals, respectively, while 82.31–100 % of As, 0–100 % of Pb and 17.82–100% of Zn were hosted in the reactive minerals, respectively. Among these studied metals, 45.78–81.73% of Cd was mainly associated with the labile fractions. PTEs presented highly pH and acidity–dependent leaching characteristics. Acidification prediction results indicated that soil pH could decrease to a value of 6 within a wide time range of 15–388 years. PTEs release were mainly controlled by the dissolution of metal–rich oxide and carbonate mineral phases, as well as the adsorption/desorption and co–precipitation/dissolution of Fe, Mn and Al bearing oxyhydroxide minerals and the complexation of dissolved organic matter (DOM). These findings would extend the knowledge to the scenario based leaching assessment studies of smelter contaminated soils.

Method for the Analysis of Respirable Airborne Particulates on Filter Using the Mineral Liberation Analyser

In recent years, the Mineral Liberation Analyser (MLA) has played a pivotal role in analysing respirable and inhalable ambient air samples collected on filters from both underground coal and metalliferous mines. Leveraging backscattered electron (BSE) image analysis and X-ray mineral identification, the MLA offers automated quantitative mineral characterization. The escalating prevalence and severity of mine dust lung diseases, particularly among young miners, have reignited interest in comprehensively understanding the dust’s characterization, encompassing mineralogy, particle size, and shape. Merely measuring total respirable dust exposure and its duration based on gravimetrically determined weight is no longer deemed sufficient in addressing the evolving landscape of occupational health challenges in mining environments. Since the publication of previous studies, efforts have been dedicated to refining the Mineral Liberation Analyser (MLA) methodology for respirable dust sampling. This refinement, discussed in detail in this paper, encompasses various enhancements, such as the implementation of data checks to identify carbon contamination, backscattered electron (BSE) drift, and the misclassification of X-ray spectra. Additionally, an examination of sampling efficiency led to the exploration of using smaller samples as an alternative to the time-intensive analysis of entire filters. Furthermore, this paper presents a reanalysis of paired filter sample sets previously reported using the Sarver Group Methodology. These samples are subjected to analysis using the Mineral Liberation Analyser, providing a more detailed illustration of the outputs derived from the updated methodology and compared to previously published MLA data.

Thiourea-assisted selective removal of arsenic from copper smelting flue dusts in NaOH solution

The selective removal of arsenic from copper smelting flue dusts is of great significance for environmental protection and resource recycling. This study employed thiourea assisted alkaline leaching to selectively extract arsenic from copper smelting flue dusts. The effects of NaOH concentration, thiourea concentration, temperature, leaching time and pulp density on the dissolution of arsenic, zinc, lead, copper and antimony in NaOH solution were studied. The results show that the addition of thiourea can effectively promote extraction of arsenic while inhibiting the leaching of zinc, lead and copper in copper smelting flue dust. Under the optimized leaching conditions, the leaching efficiencies of arsenic and antimony were 98.5% and 1.62%, respectively, while zinc, lead and copper were not leached. X-ray diffraction (XRD) analysis suggested that the addition of thiourea promoted the dissolution of insoluble arsenate minerals. The combined results of scanning electron microscopy (SEM), mineral liberation analysis (MLA), and X-ray photoelectron spectroscopy (XPS) demonstrated that thiourea prevented sulfide products from forming a coating on arsenic surface. This work has important implications for the development of processing technologies for arsenic-containing materials.

Ultrasonic pretreatment for enhancing flotation separation of elemental sulfur and silver-bearing lead minerals from an oxidative pressure leaching residue of zinc sulfide

Ultrasonic pretreatment was introduced to enhance the flotation separation of elemental sulfur and silver-bearing lead minerals from an ultrafine residue produced by oxidative pressure leaching of zinc sulfide. The particle size analysis of residue shows that ultrasonic pretreatment increases the number of particles with high sulfur content in the −19 μm fraction. This resulted from the associated sulfur was effectively liberated from other minerals. The complete liberation proportions of elemental sulfur and plumbojarosite in residue are respectively increased by 20.91 % and 38.53 % after ultrasonic treatment, in terms of mineral liberation analysis (MLA). Time-of-flight secondary ion mass spectrometry (ToF-SIMS) investigation implies that the surface structure difference between elemental sulfur and silver-bearing lead minerals is expanded by ultrasonic pretreatment. As a result, the separation of sulfur and silver-bearing lead minerals is significantly improved by ultrasonic pretreatment. Under optimized conditions of ultrasonic power, ultrasonic treatment time and solid weight, pilot-scale flotation produced a concentrate that the sulfur grade and recovery of concentrate increased by 11.63 % and 9.10 %, respectively, and the lead and silver recoveries of tailings increased by 8.72 % and 9.50 %, respectively, compared with those obtained by using the flotation without pretreatment. This work may provide an important reference for effectively recycling complex secondary resources and reducing the difficulty of subsequent values extraction.

Remining for Renewable Energy Metals: A Review of Characterization Needs, Resource Estimates, and Potential Environmental Effects

Remining has been researched for decades, but its potential to supplement virgin extraction is currently unknown. This review addresses the remining of tailings/waste rock, coal residues, and byproduct and primary production materials for renewable energy metals (e.g., Co, Ni, REEs, Mn, Li). Geochemical characterization methods for estimating pollution potential must be supplemented with mineral liberation analysis and process testing to reliably estimate remining’s economic potential. National and regional remining characterization efforts currently exist in the U.S., Europe, Australia, and China but will take years to produce viable operations at scale. Tailings hold the most promise due to their large amounts worldwide and the fact that they are already extracted and pre-processed, which reduces energy and water use. Of the processing approaches examined, bioleaching appears to offer the most benefits with the fewest potential downsides. The advantages and challenges of the processing methods and remining sources are presented. Best remining practices are urgently needed to improve resource estimates and avoid impacts such as the tailings dam failures that occurred at remining operations in Romania and South Africa. Interest in remining is booming because it can increase domestic supply. If properly conducted, remining can also improve circularity and environmental conditions in areas affected by existing and legacy mining activity.

Characterization of Nickel in Chromite Beneficiation Tailings by Mineral Liberation Analysis and Its Recovery by H2SO4 Leaching Followed by Oxalic Acid Precipitation

Characterization of Nickel in Chromite Beneficiation Tailings by Mineral Liberation Analysis and Its Recovery by H2SO4 Leaching Followed by Oxalic Acid Precipitation

A mineralogy characterisation technique for copper ore in flotation pulp using deep learning machine vision with optical microscopy

Among the flotation system process variables, mineralogy is the most difficult one to measure online. Mineralogy is typically measured through methods like Mineral Liberation Analysis (MLA) and QEMSCAN but these require sample preparation in polished sections only providing results after days or shifts. Alternatively, process plants utilise X-Ray Fluorescence (XRF) or Laser Induced Breakdown Spectroscopy (LIBS) to measure elemental grades online. However, the flotation performance is dictated by surface liberation of minerals rather than elemental grade.Recently, researchers have tried using optical microscopy to characterise mineralogy for an isolated particle, but this is not scalable for measuring process streams. This study investigates a technique utilising deep learning machine vision and optical microscopy for in-pulp characterisation of mineralogy and particle size distribution for multiple minerals in a copper ore pulp. The methodology was developed on samples from a polymetallic deposit in New South Wales, Australia that contained Cu, Pb, Zn, and Fe sulfides. This technique can predict the particle size, and mineralogy for chalcopyrite, quartz, and other sulfides in-pulp within 5 min.

Characterization of Magnetic and Mineralogical Properties of Slag Particles from WEEE Processing

Magnetic separation has wide-ranging applications in both mineral processing and recycling industries. Nevertheless, its conventional utilization often overlooks the interplay between mineral and particle characteristics and their impact on operational conditions, ultimately influencing the efficacy of the separation process. This work describes a methodology able to achieve the comprehensive characterization and classification of Waste Electrical and Electronic Equipment (WEEE) slag. The primary objective is to establish a meaningful connection between the distinct properties of slag phases and their influence on the separation process. Our methodology consists of several stages. Firstly, the WEEE slag is sieved into distinct size classes, followed by classification into magnetic susceptibility classes by using the Frantz Isodynamic separator. To quantify the magnetic susceptibility of each class, we used a magnetic susceptibility balance, and to identify paramagnetic and ferromagnetic fractions and phases within these magnetic susceptibility classes, we conducted vibrating-sample magnetometer measurements. Finally, to establish a meaningful link between the magnetic characterization, mineralogical, and particle-level details, Mineral Liberation Analysis was conducted for each magnetic susceptibility class. This in-depth analysis, encompassing both particle properties and magnetic susceptibility classes, provides a better understanding of the separation behavior of different phases and can help to enrich phases with a specific range of magnetic susceptibility values. This knowledge advances progress towards the development of predictive separation models that are capable of bridging the gap between theoretical understanding and practical application in the field of magnetic separation.