Gravity Concentration Research Articles

Transformations of Critical Lithium Ores to Battery-Grade Materials: From Mine to Precursors

The escalating demand for lithium has intensified the need to process critical lithium ores into battery-grade materials efficiently. This review paper overviews the transformation processes and cost of converting critical lithium ores, primarily spodumene and brine, into high-purity battery-grade precursors. We systematically examine the study findings on various approaches for lithium recovery from spodumene and brine. Dense media separation (DMS) and froth flotation are the most often used processes for spodumene beneficiation. Magnetic separation (MS) and ore gravity concentration techniques in spodumene processing have also been considered. To produce battery-grade lithium salts, the beneficiated-concentrated spodumene must be treated further, with or without heat, in the presence of acidic or alkaline media. As a result, various pyro and hydrometallurgical techniques have been explored. Moreover, the process of extracting lithium from brine through precipitation, liquid–liquid extraction, and polymer inclusion membrane separation employing different organic, inorganic, and composite polymer sorbents has also been reviewed.

Study of material composition and assessment of gravity concentration of oxidised polymetallic ores of RK deposit

Данная работа посвящена изучению вещественного состава окисленных полиметаллических руд и их гравитационной обогатимости. Исследованы три пробы руды и определено, что ценными компонентами в рудах является свинец и серебро. Наиболее сложной пробой является проба №1, т.к. в ней 24,15% (отн.) свинца находится в неизвлекаемой гравитацией и флотацией форме в виде плюмбоярозита. В исследуемых пробах №1 и №2 отмечается довольно высокое содержание первичных шламов (-0,04+0,0 мм), выход которых составил 38,50% проба №1 и 44,70% проба №2. Гравитационное обогащение на отсадочных машинах и концентрационном столе исследованных окисленных проб обеспечивает извлечение крупных свободных зерен церуссита в кондиционный гравитационный концентрат на уровне 44-49%, что будет снижать их переизмельчение перед флотационным обогащением и способствовать повышению общего извлечения свинца Бұл жұмыс тотыққан полиметалл кендерінің заттық құрамын және олардың гравитациялық концентрациясын зерттеуге арналған. Үш кен сынамасы зерттеліп, кендегі бағалы компоненттер қорғасын мен күміс екені анықталды. Ең қиын үлгі №1 үлгі, өйткені ондағы қорғасынның 24,15% (салыст.) гравитациямен және флотациямен бөлініп алынбайтын пішінде плумбоярозит түрінде болады. Зерттелетін №1 және №2 үлгілерде бастапқы шламның едәуір жоғары мөлшері (-0,04+0,0 мм) байқалады, оның шығымы №1 сынама үшін 38,50% және №2 сынама үшін 44,70% құрады. Зерттелетін тотыққан сынамалардың концентрациялық столда гравитациялық байыту церусситтің ірі бос түйіршіктерін стандартты гравитациялық концентратқа 44-49% деңгейінде шығаруды қамтамасыз етеді, бұл флотациялық байыту алдында олардың қайта ұнтақталуын азайтады және қорғасынның жалпы бөліп алынуын арттыруға ықпал етеді This work is devoted to the study of the material composition of oxidised polymetallic ores and their gravity enrichment. Three ore samples were studied and it was determined that the valuable components in the ores are lead and silver. The most diffi cult sample is sample No.1, because in it 24,15% (relative) of lead is in the form of plumboyarosite, which is not extracted by gravity and fl otation. In the studied samples No.1 and No.2 there is rather high content of primary slimes (-0,04+0,0 mm), the yield of which was 38,50% – sample No.1 and 44,70% – sample No.2. Gravity enrichment on jig washer and concentration table of the studied oxidised samples provides extraction of large free cerussite grains in the conditioned gravity concentrate at the level of 44-49% that will reduce their overgrinding before fl otation enrichment and contribute to increase of total lead recover

Intensification of gravity concentration of refractory gold-bearing ores

Intensification of gravity concentration of refractory gold-bearing ores

Environmentally Friendly Separating of Fine Copper Particles from Lithium Iron Phosphate and Graphite by Centrifugal Gravity Concentration

Environmentally Friendly Separating of Fine Copper Particles from Lithium Iron Phosphate and Graphite by Centrifugal Gravity Concentration

Exploring the Efficiency of Magnetic Separation and Gravity Concentration for Valorizing Pb-Zn Smelter Slag in a Circular Economy Framework.

The presented work offers an innovative process scheme for valorizing Pb-Zn slag, which involves crushing, grinding, and separation techniques to concentrate valuable components (non-ferrous metals). This methodology could have a significant impact on the global beneficiation of metallurgical slags since it is significantly more simple, environmentally friendly, and cost-effective than standard pyro- and hydrometallurgical procedures. According to previous physicochemical and mineralogical studies, Pb-Zn slag is a valuable secondary raw material. This inhomogeneous technogenic resource contains substantial amounts of non-ferrous metals (Pb, Zn, Cu, and Ag). However, laboratory tests have indicated that the Pb-Zn slag contains highly uneven amounts of valuable metals, ranging from several g/ton to tens of g/ton. The main issue is that traditional metallurgical procedures for releasing beneficial elements are not commercially viable since the elements are "trapped" within the amorphous aluminosilicates or intergrowths of alloy grains and glassy phases. Gravity concentration (Wilfley 13 shaking table) and magnetic separation (Davis separator and disk separator) were used to obtain the final concentrate following comminution and grindability testing. The gravity concentration proved more effective. Namely, magnetic separators could not process nor adequately separate beneficial non-ferrous elements because they were merged together with iron-bearing minerals and aluminosilicates in amorphous Pb-Zn slag grains. With the gravity concentration approach, 12.99% of the processed slag belonged to ∆T fraction (concentration of non-ferrous metal alloys), while remaining 87% corresponded to the tailings fraction (∆L). The total amounts of recovered Pb, Zn, Cu, and Ag from ∆T and ∆L fractions were 5.28%, 6.69%, 0.58%, and 76.12 ppm and 1.22%, 6.05%, 0.43%, and 15.26 ppm, respectively. This streamlined approach to valorizing Pb-Zn slag can reduce the need for hazardous chemicals used in hydrometallurgical refinement operations, as well as the extremely high temperatures required for pyrometallurgical processing. This is the first study to investigate the viability of this novel methodology, which involves the direct examinations of the Pb-Zn slag feed with various alternative technologies for separation and concentration. After extracting the valuable metals, the amorphous aluminosilicate part of the Pb-Zn slag can be reapplied as an alternative raw material in the building sector, adding to the circularity of the suggested approach.

Gold occurrence in the footwall of the Lappberget Deposit, Garpenberg Mine, Sweden: Implications for recovery efficiency

By-product metals have a significant potential to bring additional economic benefits to mines. However, a detailed characterization of their distribution is generally required to fulfill this potential and should preferably be integrated into a geometallurgical assessment. This contribution presents a detailed mineralogical and textural investigation of gold-bearing phases at the footwall of the Zn–Pb–Ag–(Cu–Au) Lappberget Deposit, Garpenberg Mine, Sweden, using optical microscopy, scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), electron probe microanalysis (EPMA), laser ablation-inductively coupled plasma mass spectrometer (LA-ICPMS), and bulk chemical analysis applied to drill core and Knelson concentrator samples. Gold is a by-product at the Garpenberg mine, but it is unclear how the mineralogy, occurrence, and distribution of gold-bearing phases impact on gold recoveries during mineral processing. Our results show that Au-dominant electrum is the most abundant gold-bearing phase in the footwall of the Lappberget deposit, occurring strongly associated to sulfides in a variety of textures and grain sizes. Electrum grains commonly occur within sulfide borders, as inclusions, intergrowth and overgrowths of chalcopyrite, pyrite, galena, sphalerite, and pyrrhotite. Gangue minerals may also contain disseminated electrum and inclusions. Electrum grain sizes range from ∼5 µm to 300 µm, predominantly below 100 µm. The potential of sulfide lattice-bound invisible gold in the form of solid-solution gold and colloidal gold was also investigated, showing Au depletion within the analyzed sulfide carriers. The analysis of the concentrate samples from the Knelson gravity concentrator showed 584 and 431 ppm of gold content. High degree of liberation is observed among the gold-bearing phases in the concentrate, and gold recovery is highest among fractions coarser than 106 µm mesh. Pyrite and galena are the most abundant minerals in the concentrate samples. The gold-bearing phases were categorized based on its mineralogy, texture, grain size, and association and their influence on gold processing, especially textures and grain size, which implicates its liberation in milling and recovery by the gravity separator.

Epigenome-wide association study of fluoride exposure during early adolescence and DNA methylation among U.S. children

Exposure to fluoride in early childhood has been associated with altered cognition, intelligence, attention, and neurobehavior. Fluoride-related neurodevelopment effects have been shown to vary by sex and very little is known about the mechanistic processes involved. There is limited research on how fluoride exposure impacts the epigenome, potentially leading to changes in DNA methylation of specific genes regulating key developmental processes. In the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), urine samples were analyzed using a microdiffusion method to determine childhood urinary fluoride adjusted for specific gravity (CUFsg) concentrations. Whole blood DNA methylation was assessed using the Infinium MethylationEPIC BeadChip 850 k Array. In a cross-sectional analysis, we interrogated epigenome-wide DNA methylation at 775,141 CpG loci across the methylome in relation to CUFsg concentrations in 272 early adolescents at age 12 years. Among all participants, higher concentrations of CUF were associated with differential methylation of one CpG (p < 6 × 10−8) located in the gene body of GBF1 (cg25435255). Among females, higher concentrations of CUFsg were associated with differential methylation of 7 CpGs; only three CpGs were differentially methylated among males with no overlap of significant CpGs observed among females. Secondary analyses revealed several differentially methylated regions (DMRs) and CpG loci mapping to genes with key roles in psychiatric outcomes, social interaction, and cognition, as well as immunologic and metabolic phenotypes. While fluoride exposure may impact the epigenome during early adolescence, the functional consequences of these changes are unclear warranting further investigation.

Can preconcentration of cassiterite from its pegmatite ore reduce processing costs and improve operational sustainability?

Different concentration techniques were evaluated for preconcentration of a mineral ore at a coarser size to avoid energy and resource wastage. Specifically, the aim was to reduce milling costs and energy required in the beneficiation of tin. In this study, cassiterite (0.17% Sn) was the mineral of interest in a pegmatite ore body associated with quartz (SiO2 &gt; 60%) and alumina (Al2O3 &gt; 20%). Three concentration techniques, namely dense media, shaking table, and flotation, coupled with characterization analysis, were used to assess the concentration response. The results confirmed that particle size and mineral liberation impact the separation process. High recovery and grade were obtained with gravity concentration methods (dense media and shaking table) for coarser (+300 to +212 μm) and intermediate (+150 to +53 μm) particle sizes. Lower recovery and grade were identified for much finer sizes (-53 to -38 μm). Flotation produced a high-grade product at a relatively low recovery and appeared to be only applicable to finer grains. Separation efficiency based on Schulz's equation measured a segregation performance of 74.8% for dense medium separation and 60.7% for the shaking table for the coarse and intermediate particle sizes. Flotation only achieved a separation of 30%-40%. The results suggest that use of dense media separation as a rough preconcentration method prior to further grinding, and the utilization of a more advanced concentration technique for mineral recovery and upgrade, constitute a successful approach to improve process economics.

Characterization and concentration of U, Nb, Pb, Ag, and Fe from the Huayangchuan polymetallic ore

The separation and recovery of valuable metals from the Huayangchuan uranium polymetallic ore was investigated based on mineralogical research and mineral processing experiments. The most promising valuable elements in the ore, according to mineralogical studies, are U, Nb, and Pb. 95.75% of U and 93.00% of Nb are found in betafite, 46.85% of Pb is present in galena, 52.01% of Pb occurs in cerussite, and associated Ag exists primarily in galena. The beneficiation process involving gravity concentration, magnetic separation, and flotation was determined based on the mineralogical characteristics of the ore. The U-Nb concentrate with U grade of 3578 ppm and recovery of 83.18 %, Nb&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; grade of 4391 ppm and recovery of 74.55 % can be obtained, and five elements including U, Nb, Pb, Ag, and Fe are recovered. Compared with the previous beneficiation experimental process, the flowsheet is greatly simplified and the beneficiation recovery efficiency has been improved. The results of this investigation can help to address the gaps in the processing of low-grade uranium deposits with similar mineralogical properties.

Investigating the Gravity Beneficiation Consequence on Farin-Lamba (Plateau State) Cassiterite towards Tin Oxide Production

This research aims to assess the amenability of Farin-Lamba cassiterite to the gravity concentrations techniques towards tin oxide production. The ore was subjected to fractional sieve size analysis, work index, and the concentration test to gravity method using the Wilfley shaking table and Spiral concentrator processing. Fractional sieve analysis of the crude sample was carried out at a sieve range of 500-63 µm towards liberation size determination. Five hundred (500) g each of Farin-Lamba cassiterite and Igbokoda silica sand was prepared by grinding to 100% passing 500 μm sieve towards work index determination and the gravity separation method was determined using the Wilfley shaking table and spiral concentration method. The fractional sieve size analysis carried out revealed that the Tin oxide-bearing mineral can be liberated at the particle size fraction of -180 + 125 μm. The work index alongside the energy expended in grinding the ore was found to be 9.980 Kwh/ton and 2.435 Kwh respectively. The chemical analysis of the ore concentrates revealed that the optimum yield was obtained at +125 µm assaying 62.74% SnO2 for Wilfley shaking table and 60.07% SnO2 for spiral concentration.

First results of using mineral concentration methods for metal recover from technogenically contaminated soils with significant organic concentrations

The purpose of the article is to present the research results on the application of concentration methods to hazardous waste from the industrial site of the former Vostsibelement battery plant located in the town of Svirsk, Irkutsk region (Russia), which is the facility of accumulated environmental damage. The previous studies have identified significant contents of heavy metals and arsenic that exceed standard values by hundreds and thousands of times in the industrial site soils. This fact determines soil high hazard class – II and III. To reduce the hazard class and decrease the volume of hazardous waste it is proposed to use a recuperative approach, that means to recover some metals and arsenic in order to return them in economic circulation. A spiral concentrator, a shaking table and a centrifugal concentrator were used for gravity concentration of metals and arsenic. The best results were obtained using a shaking table. The latter made it possible to increase the lead content in the concentrate by 22 times as compared to the content in the original sample, arsenic content by 7.7 times, and iron content by 16.7 times. Magnetic concentration of the shaking table middlings made it possible to obtain a concentrate with a high content and recovery of iron, copper and zinc. Despite the fact that the soil waste contains a significant amount of organic matter unlike the case of ore processing, the possibility of successful metal recover and significant reduction of metal concentrations in soil is shown. The proposals for a further waste-recycling scheme are made on the basis of the data obtained.

Reapplication Potential of Historic Pb–Zn Slag with Regard to Zero Waste Principles

Smelting used to be less efficient; therefore, wastes obtained from historical processing at smelter plants usually contain certain quantities of valuable metals. Upon the extraction of useful metal elements, metallurgical slag can be repurposed as an alternative mineral raw material in the building sector. A case study was conducted, which included an investigation of the physico-chemical, mineralogical, and microstructural properties of Pb–Zn slag found at the historic landfill near the Topilnica Veles smelter in North Macedonia. The slag was sampled using drill holes. The mineralogical and microstructural analysis revealed that Pb–Zn slag is a very complex and inhomogeneous alternative raw material with utilizable levels of metals, specifically Pb (2.3 wt.%), Zn (7.1 wt.%), and Ag (27.5 ppm). Crystalline mineral phases of wurtzite, sphalerite, galena, cerussite, akermanite, wüstite, monticellite, franklinite, and zincite were identified in the analyzed samples. The slag’s matrix consisted of alumino-silicates, amorphous silicates, and mixtures of spinel and silicates. Due to the economic potential of Pb, Zn, and Ag extraction, the first stage of reutilization will be to transform metal concentrates into their collective concentrate, from which the maximum amount of these crucial components can be extracted. This procedure will include combination of gravity concentration and separation techniques. The next step is to assess the Pb–Zn slag’s potential applications in civil engineering, based on its mineralogical and physico-mechanical properties. Alumino-silicates present in Pb–Zn slag, which contain high concentrations of SiO2, Al2O3, CaO, and Fe2O3, are suitable for use in cementitious building composites. The goal of this research is to suggest a solution by which to close the circle of slag’s reutilization in terms of zero waste principles. It is therefore critical to thoroughly investigate the material, the established methods and preparation processes, and the ways of concentrating useful components into commercial products.

Investigating the Production of Ultrafine Engineering Material from Low-Grade Gariti Barite Ore Using Gravity Concentration Methods

The objective of this research is to upgrade the low-grade Gariti barite ore to produce an ultrafine engineering material that can be used for industrial application by the assessing gravity concentration method. The research focuses on chemical characterization, fractional sieve size analysis, scrubbing technique, wilfley shaking table technique, and air float technique. The sample was subjected to an energy-dispersive X-ray fluorescence spectrometer and fractional sieve analysis of the crude sample was carried out at a sieve range of 1400-63 µm towards the production of ultrafine mineral-based material for liberation size determination. Ten (10) kg, each of the actual liberation size were used for the scrubbing technique, wilfley shaking table technique, and air float technique respectively. The chemical analysis indicates the presence of major elements 79.20 % BaSO4, 14.4% SO3, 64.80% BaO, 3.80% Fe2O3, 5.15% SiO2, 1.40% TiO2, and other minor elements that confirms that the soured mineral is barite while the particle size analysis showed that -250+ 180 µm sieve size fraction assaying 89.11% BaSO4 is the ore’s actual liberation size. The chemical analysis of the low-grade Gariti Barite ore after undergoing a concentration test at the economic liberation size revealed the values of concentrates from the scrubbing technique to be 86.60% BaSO4, Wilfley shaking table technique to be 86.10% BaSO4, and air float technique to be 88.30% BaSO4 and from this results, it shows that air float technique had the highest assaying value. Finally, the low-grade Gariti barite ore has been upgraded from 79.20% BaSO4 to ultrafine mineral-based engineering material of 86.60%, 48.6% 86.10%, and 88.30% BaSO4 via gravity concentration method.

Gravity Concentration in Urban Mining Applications—A Review

Urban mining has emerged as a concept that goes beyond conventional recycling, as it aims to tackle both the challenges of solid waste generation and management, as well as the scarcity of primary resources. Gravity concentration has gained increasing attention as a promising method for addressing crucial challenges in urban mining applications. In this sense, this review provides a comprehensive and up-to-date overview of gravity concentration in urban mining processes, covering principles, techniques, current applications, recent advancements, challenges, and opportunities. Emphasis was placed on shifting from the commonly found literature focus on ore processing to solid waste processing. Three types of solid waste, namely plastics, construction and demolition waste (CDW), and waste from electrical and electronic equipment (WEEE), were chosen for a more in-depth examination due to their massive production and widespread generation. Discussions also considered the potential of gravity concentration to address the unique challenges in their processing and explored possibilities for future developments.

Effect of feed-size segregation on energy consumption during jigging: A CFD-DEM study

Segregation of feed based on size is used to increase the efficiency of gravity concentration by jig devices. Due to the variety of size and density of the particles in the feed, choosing how to segregate it before jigging is still a challenge. This article segregates the feed (with a size range of 3 to 8 mm) into the different states and then, simulates the jigging performance with the two-way coupling method of computational fluid dynamics and the discrete element method in 3 dimensions. In different states, the energy consumption and the number of cycles required for gravity concentration were compared, qualitatively. The simulation shows that the segregation of the jig feed into two size classes (3 to 4) and (5 to 8) mm decreases the energy consumption and the number of cycles. Therefore, the segregation state where the fine-grained part has a close size range and the coarse-grained part has a wide size range will have the lowest energy consumption and the number of cycles.

Characterization and gravity concentration studies on spodumene bearing pegmatites of India

ABSTRACT The exclusive properties of lithium make it indispensable for its diversified applications, resulting in a steep increase in the present-day demand. In the present investigation, characterization and laboratory beneficiation studies were carried out on the spodumene-bearing lithium pegmatites of India. The major minerals associated with the sample are spodumene, quartz, albite, orthoclase, and muscovite. The chemical analysis results of the collected samples show a variation of Li2O content between 0.02 to 1.85%. The gravity concentration studies were carried out on the feed material with a Li2O content of 1.10%. Gravity concentration studies following heavy liquid separation (HLS), mineral jig, shaking table, and Falcon concentrator were used to enrich the spodumene content. The sink and float analysis on feed material showed that the spodumene mineral is fairly liberated. A better separation of spodumene from the associated silicate gangue was achieved in HLS and mineral jig. Even though fine particles liberated well, separation in the shaking table and Falcon concentrators were inferior due to lower concentration criteria (CC-1.33). Further, the separation efficiency (SE) has been computed for all gravity concentrators. HLS has higher SE than the mineral jig, shaking table, and Falcon concentrator for separating spodumene from the silicate gangue.

Kajian Teknis Pengolahan SHP menggunakan Shaking Table untuk Mengoptimalkan Kadar dan Recovery Sn di TB Batu Besi PT Timah Tbk

PT Timah Tbk carried out the development by establishing TB Primer Batu Besi, East Belitung. The purpose of this study was to find out the variable setting of the shaking table in order to obtain optimal levels and recovery of Sn. The research method used is gravity concentration using a shaking table tool. The feed used is Remaining Processing Results from the primary shaking table. The experiment was carried out twice, the first experiment was carried out 27 times with a sample weight of ± 78 kg. Each experiment used 9 variations, namely the tilt of the shaking table (8°;8.5°;9°) and the stroke length (12mm, 14mm, 16mm). The second experiment used ±5 tons of material with the most optimal tool settings from the first experiment. The feed sample material and product shaking table were tested using the XRF and GCA tests. The analysis of the XRF test showed that the Sn content in the feed was 0.45%. GCA analysis shows that the associated minerals are cassiterite, ilmenite, monazite, pyrite, quartz, tourmaline, hematite and magnetite. The optimal setting for the operating variable of the shaking table is with a variation of the tilt of the shaking table 8° and a stroke length of 12 mm to obtain a concentrated Sn content of 8.04% and a concentrated Sn recovery of 20.75%. The second experiment obtained a total Sn recovery of 17.25%. If one additional SHP processing line is added to TB Batu Besi, the company's recovery will increase from ±15% to ±29.55%.

Performance evaluation of Falcon fluidized bowl and ultrafine (UF) bowl concentrators for the recovery of ultrafine scheelite particles

The recent developments in enhanced gravity concentrators, such as Falcon centrifugal separators, are proven beneficial in treating fine and ultrafine mineral particles. This concentrator is classified into a fluidized bowl concentrator and an ultrafine (UF) bowl concentrator based on the bowl design, which has considerable significance in facilitating the separation process. The present investigation concerns the recovery of ultrafine scheelite particles present in the gold mine tailing with an average WO3 content of 0.08%. The separation behaviour and application of different bowls concerning various particle sizes have been investigated. It is found that the Falcon UF concentrator can achieve a high recovery while the Falcon fluidized bowl can obtain a higher grade. Further, the fluidized bowl was found more effective at eliminating entrapped calcite mineral particles than the UF bowl. The effectiveness of both bowls is assessed in recovering heavy particles of various sizes, and the results show that the fluidized bowl performs better in recovering coarser heavy particles, while the UF bowl performs better in recovering fine heavy particles. Based on these findings, an integrated circuit (fluidized and UF bowls) has been designed, which resulted in achieving a higher (85%) recovery of WO3 values compared to individual bowls.

Recycling of Chrome-Containing Waste from a Mining and Processing Plant to Produce Industrial Products

Prolonged development of ore deposits, ore beneficiation and metallurgical smelting of concentrates result in the accumulation of wastes, forming large-scale dumps and sludge ponds negatively affecting the environment and human health. The creation and introduction of industrial waste treatment technologies will make it possible to dispose of them with the production of valuable commercial products and improve the environmental situation. In a research article on chemical beneficiation with the subsequent gravitational beneficiation of chrome-containing slurry tailings of Donskoy Ore-Mining and Beneficiation Plant (DOMBP), which processes chrome ore of the Kempirsay deposit in the Republic of Kazakhstan, Aktobe region, having considerable stocks of such waste is presented. The chromium-containing slurry tailings were heat-treated at 1100 °C, sintered with ammonium sulfate, water and sulfuric acid in a defined ratio at 300 °C, and then the resulting sinter was leached with water at 90 °C. The cake was washed to separate the liquid part from the solid part. The solid precipitate is the chromium-containing cake, which is upgraded by gravity concentration to a grade concentrate for ferroalloy production. When the solution is evaporated, magnesium sulfate with ammonium sulfate forms the Tutton’s salt ammoshenite. High-throughput chromium oxide extraction of 93.9% was achieved as a result of the research, and three products were obtained: (1) standard chromium concentrate with 49.48% Cr2O3 content, (2) ammoshenite used as a nitrogen–magnesium fertilizer and (3) forsterite, which is concentrated in gravity concentration tailings and can be used in the production of refractory minerals.

Automated and Quantitative Mineralogy Applied to Chromite Ore Characterization and Beneficiation

A characterization study of chromite ore from South Africa was conducted using bulk assays, X-ray diffraction, optical, scanning electron microscopy (SEM), automated electron probe microanalysis (EPMA) and quantitative evaluation of mineral by scanning electron microscopy (QEMSCAN) mineralogical techniques, and quantitative EPMA. The aim was to identify all major gangue impurities, the degree of chromite liberation, and possible beneficiation options. The bulk material assayed 40.5% Cr2O3 with the major impurities being Al2O3 (13.2%), MgO (12.1%), and SiO2 (7.5%). Quantitative mineral phase analysis showed that the sample mineralogy was dominated by a chrome-rich spinel phase with an average chemical composition (in wt.%) of: Cr2O3—47.8; FeO—26.0; Al2O3—15.4; and MgO—11.0. Contaminant phases included siliceous minerals enstatite, anorthite-rich plagioclase (bytownite), Cr-rich diopside (containing 1–2 wt.% Cr2O3), and phlogopite mica. QEMSCAN analysis of sized fractions indicated that (a) most silicate gangue species were in the +850 μm fractions, (b) the chrome-rich spinel in all fractions was &gt;80% liberated, and (c) the most common mineral association for chromite was with enstatite. Based on the results, upgrading test work demonstrated that stage crushing followed by wet gravity concentration produced a chemical–metallurgical-grade ‘chromite’ product containing &gt;46% Cr2O3 and &lt;1% SiO2.