Search Results (663)

This study investigated lithium beneficiation from nepheline syenite ore containing 242.57 ppm Li, identifying biotite as the primary lithium-bearing mineral. A high-intensity dry magnetic separation produced a pre-concentrate assaying at approximately 850–1000 ppm Li, and flotation tests were conducted on both the run-of-mine ore and this magnetic product. Flotation performance was systematically evaluated using two top sizes (−500 and −300 µm), six size fractions (−500 + 75, −500 + 53, −500 + 38, −300 + 75, −300 + 53, −300 + 38 µm), four pH values (2.5, 4.0, 6.5, 9.5), and three collectors (DAHC, Derna 7, and Der A4). Among the reagents, Der A4 yielded the most promising results. Optimization using sodium silicate as a depressant demonstrated that, at 20 g/t Der A4, 500 g/t Na₂SiO₃, and pH 4.0, the −300 + 75 µm fraction of the run-of-mine ore reached approximately 5300 ppm Li. Applying the same parameters to the magnetic pre-concentrate resulted in a 6326.46 ppm Li concentrate with roughly 80% of flotation recovery. Mineralogical characterization using MLA, XRD, modal mineralogy, and SEM-EDS confirmed that the optimized product consisted predominantly of biotite, accompanied by K-feldspar, nepheline, and albite. Liberation results showed high liberation levels and the free surface, supporting the efficiency of combining magnetic separation with flotation for upgrading nepheline syenite as a potential lithium resource. Full article

The oily wastewater produced by transformer oil leakage contains pollutants such as mineral oil, metal particles, aged oil and additives, which can disrupt the dissolved oxygen balance in water bodies, pollute soil and endanger human health through the food chain, causing serious environmental pollution. Effective oil–water separation technology is the key to ecological protection and resource recovery. This paper reviews the principles, influencing factors and research progress of traditional (gravity sedimentation, air flotation, adsorption, demulsification) and new (nanocomposite adsorption, metal–organic skeleton materials, superhydrophobic/superlipophilic modified films) transformer oil–water separation technologies. Traditional technologies are mostly applicable to large-particle-free oil and are difficult to adapt to complex matrix wastewater. However, the new technology has significant advantages in separation efficiency (up to over 99.5%), selectivity and cycling stability (with a performance retention rate of over 85% after 20–60 cycles), breaking through the bottlenecks of traditional methods. In the future, it is necessary to develop low-cost and efficient separation technologies, promote the research and development of intelligent responsive materials, upgrade low-carbon preparation processes and their engineering applications, support environmental protection treatment in the power industry and encourage the coupling of material innovation and processes. Full article

This study evaluates sensor-based pre-concentration using XRT technology as an alternative to selective mining for low-grade European copper ores (0.48% Cu), addressing the need for sustainable beneficiation amid declining ore grades and environmental pressures in green mining initiatives. Copper ore samples from Złote Hory mine (Czech Republic) were selectively extracted, mixed (1:1:1 ore 8–16 mm/ore 16–32 mm/waste rock 8–32 mm), and analyzed on Comex’s LSX-MAX laboratory sorter with dual-energy XRT sensors, calibrated for maximum product recovery via density-based classification into High-Density (product) and Low-Density (waste) fractions. Sorting achieved a 1:1 product-to-waste mass split from feed (Cu = 0.5%, 100% mass), yielding pre-concentrate at 0.91% Cu (52.08% mass yield, 95.67% recovery) and waste at 0.04% Cu (47.92% mass, 4.33% loss)—a 1.82x grade upgrade superior to mixed feed and 1.42x superior to selective mining (0.64% Cu at 66.21% yield). Combined approaches promise further optimization; future work will assess downstream grinding/flotation impacts, industrial scaling, and economic/environmental benefits. Full article

The flotation effect of the new collector, 2-octylthio(aniline) (2-OA), on two types of sulfide ores under various conditions was investigated and compared with that of the conventional collector, potassium amyl xanthate (PAX). Collector 2-OA showed better floatability in copper sulfide ore flotation, and the copper grade could be enriched up to 1.5 times the original ore during the secondary flotation of copper sulfide ore. Compared to PAX, 2-OA demonstrated a stronger ability to collect copper than iron. Furthermore, in the flotation of gold sulfide ore, a 13% higher gold recovery was achieved with 2-OA than with PAX. Surface chemical analysis showed that 2-OA altered the surface charge of minerals and formed Cu–S and Cu–N bonds on the chalcopyrite surface. The adsorption capacity of 2-OA exceeded that of PAX, thereby enhancing the flotation effect. Overall, 2-OA exhibits better flotation performance and potentially serves as an efficient collector for sulfide ore flotation. Full article

The depletion of the mineral resource base is inevitable. Therefore, it is necessary to adapt and expand the resource base by incorporating non-traditional copper sources in production. Slag samples from the Balkhash Copper Smelting Plant (Kazakhstan) were analyzed for phase composition, microstructure, and metal distribution using X-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical and granulometric methods. The slags are characterized by a fayalite structure with a high content of FeO (35–45%) and SiO₂ (25–35%). Sample composition was determined as 0.7–0.8% Cu, 0.39–0.43% Pb, 2.53% Zn, 0.075 g/t Au, and 2.6 g/t Ag. Mineralogical and granulometric analysis revealed a uniform distribution of iron and slag-forming components (SiO₂, Al₂O₃, etc.) across the fractions. In contrast, non-ferrous and precious metals concentrated in the fine classes. Laboratory tests confirmed that the fine dissemination of valuable components led to low efficiency in magnetic and gravity separation, necessitating specific preliminary slag preparation to improve recovery. Flotation tests showed improved recovery, yielding copper concentrates with 4.57% copper content when the material was crushed to 80–90% of the −0.074 mm class. The research creates a basis for the development of environmentally safe and resource-saving technologies and provides initial data for future recovery technologies. Full article

Low-grade Cu-Ni-PGM concentrators increasingly operate under the combined constraints of declining ore grades, variable process water quality, and the need to optimise reagent suites for sustainable production. This study examines the performance of mixed thiol collectors under controlled inorganic electrolyte conditions representative of modern concentrator water circuits. A comprehensive review of mixed-collector flotation is followed by a bench-scale experimental programme using sodium isobutyl xanthate (SIBX), sodium diethyl dithiophosphate (SEDTP), and their mixtures, tested in synthetic plant water and in CaCl₂ and NaCl solutions at fixed ionic strength. Results show that increasing the SEDTP molar fraction significantly enhances froth stability, water recovery, and solids recovery across all water types, driven by stronger surface activity and the presence of surface-active impurities. Ca²⁺ bearing process water promoted the highest Cu and Ni recoveries but also intensified gangue recoveries at high SEDTP levels, lowering concentrate grades. In contrast, SIBX-rich mixtures yielded superior selectivity, particularly in Na⁺ containing process water. Mechanistic interpretation shows that combined effects of electrical double-layer compression, mineral activation, mixed-collector adsorption, and froth stabilisation behaviour govern the observed grade–recovery trends. Overall, this study demonstrates that thiol-collector synergy is strongly water-chemistry-dependent, and that optimising collector mixtures requires coordinated control of reagent composition and process water quality. The findings provide a mechanistic basis for water-responsive reagent design in Cu-Ni-PGM flotation circuits. Full article

To elucidate the refractory depression of serpentine in a Jinchuan copper-nickel ore (Located in Gansu Province), this study compared the effects of serpentine from Gansu and Liaoning on chalcopyrite flotation via single/mixed mineral flotation, zeta potential, micro-polarity detection, XPS, ToF-SIMS, and EPMA. Single mineral flotation showed chalcopyrite recovery reached ~90% at pH < 8 with 60 mg/L DDTC, while Gansu serpentine had slightly higher recovery than Liaoning serpentine. In mixed mineral flotation, chalcopyrite recovery dropped to ~70% (pH = 8), and Gansu serpentine recovery rose to ~45% (vs. ~35% for Liaoning). When 40 mg/L CMC inhibitor was added, chalcopyrite recovery restored to ~80%, and both serpentines’ recovery fell below 20%—but serpentine (Gansu) still had marginally higher recovery. The zeta potential and micro-polarity experiments collectively indicate that the collector exhibits selective adsorption on the surface of chalcopyrite; compared between the two serpentine samples, the collector adsorption is stronger on the surface of Gansu serpentine. In contrast, the depressant shows selective adsorption on the surface of serpentine, but when comparing the two serpentine samples, the depressant adsorption is stronger on the surface of exotic serpentine. This finding to a certain extent explains the reason why Gansu serpentine is difficult to depress. EPMA showed Gansu serpentine had lower MgO (38.668% vs. 41.012% for Liaoning), and XPS exhibited smaller Mg 1s shifts (1.93 eV vs. 4.46 eV) with CMC. This study explains Gansu serpentine’s poor depressibility, providing critical support for optimizing Cu-Ni ore flotation reagents and processes, gradually bridging to industrial application. This work provides a universal framework for global low-grade copper-nickel ores with silicate gangues. Full article

Ferrate as an environmentally friendly oxidant has been widely used in the environmental remediation and versatile functionalization of carbon-based materials. In this study, we investigated its ability to induce surface wettability of polymers and its emerging applications in separating mixed plastics through flotation for recycling. It was found that ferrate (VI) formed oxygen-containing groups on the surface of polycarbonates (PCs) by selectively oxidizing the sp³-hybridized carbon atoms into hydroxyl and carboxyl moieties, in addition to introducing nanoscale iron oxides. This facilitated the selective hydrophilization of PC with a water contact angle of 60.7° but did not clearly affect the surface wettability of polyvinyl chloride (PVC). This difference in surface wettability highlighted the distinct floatability properties of PC and PVC, which can be utilized to separate mixtures of these plastics with the aid of flotation. A central composite design (CCD) utilizing response surface methodology (RSM) was applied to model ferrate oxidation and to optimize flotation. Under the optimized conditions, mixtures of PC and PVC were efficiently separated with recovery and purity values of more than 99.8 ± 0.3%. Our findings provide a rational understanding of polymer wettability tailoring and expand its emerging applications in waste plastic recycling to address environmental problems. Full article

In addition to seawater in the injection header (IH) to enhance oil recovery, oil companies reuse produced water (PW), a byproduct of oil extraction, and implement produced water reinjection systems (PWRI). Although the microorganisms in IH are controlled by biocides, PW is generally treated by flotation to remove oil residues before PWRI. However, IH, PW, and PWRI can be sources of sulfate-reducing bacteria (SRB) related to oil reservoir souring. Here, we evaluated hydrogen sulfide (H₂S) production in IH, PW, and PWRI, as well as the microbial dynamics (most probable number–MPN, quantitative PCR, and amplicon sequencing), of a Brazilian oil reservoir. Results revealed that the highest average H₂S concentration occurred in PW samples. However, the dissolved H₂S threshold concentration of 2 mg L⁻¹ was exceeded in 18% of PW and ~16% of PWRI samples, respectively. Although MPN showed no correlation between H₂S and the number of SRB or total anaerobic heterotrophic bacteria (TAHB), qPCR and microbiome data revealed that the SRB Desulfobacterota was the most abundant in PW and PWRI. Overall, flotation was associated with (i) low microbial control in PW; and (ii) the enrichment of SRB (mainly Desulfobacterota), Thermotogota, and Proteobacteria groups in PWRI. Full article

New intensified flotation technologies have emerged to enhance fine and ultrafine particle recovery. However, their modelling remains challenging, as it requires defining the effective collection volume, residence time, and internal recirculation, factors not included in conventional models, while also facing operational complexity and the limited availability of key hydrodynamic and kinetic data. This study presents the development of a flotation model for the Concorde Cell technology, which separates the flotation process into three stages: collection zone, separation tank, and froth transport. The collection zone was represented as a plug-flow reactor with a rectangular rate of constant distribution; the separation zone as a perfect mixer with a detachment efficiency factor; and the froth recovery as a function of froth stability, residence time, and transport distance. Water recovery and gangue entrainment were also modelled to estimate concentrate grades. The model was tested and calibrated using experimental results from tests conducted in a Concorde Cell Lab Unit. A case example is presented for a semi-batch exhausting test performed with minerals from a copper concentrator plant. Good agreement between simulated and experimental results demonstrated the robustness and flexibility of the model. Additionally, the results showed collection rate constants significantly higher than those typically reported for conventional flotation cells (more than 100 times higher for Cu), due to the smaller collection volume and shorter residence time in the Concorde Cell. The calibrated model was then applied to simulate an industrial operation, where sensitivity analyses showed consistent responses to variations in operating conditions. Overall, the proposed model provides a practical tool for predicting the metallurgical performance of intensified flotation cells, supporting the integration of this new technology into modern concentrator flowsheets for the development of hybrid circuits. Full article

Sphalerite (ZnS), the primary zinc-bearing mineral in most sulfide deposits, exhibits poor natural floatability and requires activation by metal ions such as Cu²⁺ or Pb²⁺. Copper sulfate (CuSO₄) is the most common activator, but its use at high dosages introduces sulfate accumulation and necessitates separate pre-conditioning to prevent the formation of inactive copper xanthates. This study investigates a novel copper–amine complex, Zn Flooter (ZnFL), as an alternative activator for sphalerite flotation. ZnFL is a liquid reagent containing stabilized ionic copper with a significantly lower sulfate content. Contact angle and flotation tests were conducted on two sphalerite-bearing ores of different mineralogy (Pb–Zn and Cu–Zn types). Contact angle tests showed that ZnFL (68–71°) enhances sphalerite surface hydrophobicity more effectively than CuSO₄ (61–66°). In flotation, ZnFL at 100 g/t achieved recoveries and grades comparable to those for CuSO₄ at 500 g/t, while allowing simultaneous addition with the collector without loss of performance. ZnFL also exhibited improved sphalerite/pyrite selectivity and did not negatively affect froth stability. These results demonstrate that ZnFL can provide equivalent or superior activation efficiency at a lower dosage and with simplified operation. Further studies on adsorption mechanisms and water chemistry effects are recommended to validate its industrial potential as a sustainable activator for sphalerite flotation. Full article

An eco-friendly flotation process is of great significance to the green and sustainable development of the mining industry. The purpose of this study is to improve the traditional flotation process. Novel reagents, alkyl ether amine (Alkyl carbon chains with a length of 12 are simply referred to as DOEA) as collector and carboxymethyl starch (CMS) as depressant, were used for flotation uAlkyl ether aminender lower temperature, which did not need to heat the tonnage of pulp and reduced the energy consumption. The micro-flotation tests were carried out with three main minerals (quartz, hematite and magnetite) contained in Qidashan (Anshan, China) iron ore at room temperature in winter (18 °C). The bench-scale tests were carried out with flotation feed (mixture of strong magnetic concentrate and weak magnetic concentrate) from the Qidashan flotation workshop at room temperature (18 °C). And the industrial tests were carried out in the flotation workshop of Qidashan Concentrator of Anshan Iron and Steel Co., Ltd. The temperature of the pulp was 17.5~19.7 °C. The results of micro-flotation tests showed that the floatability of the three minerals under the DOEA system decreased in the following order: quartz > hematite > magnetite. The addition of CMS increased the floatability difference between quartz and ferric oxide minerals. DOEA and CMS could effectively separate quartz and ferric oxide minerals at room temperature in winter. The feasibility of the application of DOEA and CMS in Qidashan iron ore was verified by bench-scale tests, and the pulp circulation process was simulated by locked-cycle tests. The results of bench-scale tests showed that under the conditions of CMS dosage 200 g/t, DOEA dosage 150 g/t, and pulp temperature 18 °C, the iron grade of flotation concentrate was 66.54% and iron recovery was 78.37%. The industrial test results showed that the modified flotation process could continuously output qualified iron concentrate without heating the pulp. Compared with the on-site flotation process, it was found that the modified flotation process could save USD 6,460,100 per year. This technology could significantly reduce the energy consumption of iron ore reverse flotation, reduce the carbon emissions generated by heating tons of pulp, and achieve cleaner production. Full article

Quartz and feldspar have similar physical, chemical, and surface properties. Effectively separating them in near-neutral systems has long been a challenging research focus. This study introduces 1-Dodecyl-3-methylimidazolium bromide (DMB), an ionic liquid, as a collector in a quartz–feldspar flotation separation system to investigate its effects on the flotation behavior of quartz and feldspar. The interaction between the collector and the minerals is explained through zeta potential measurements, infrared spectroscopy analysis, and DFT calculations. The flotation test results indicate that DMB exhibits selective flotation separation properties enabling the separation of quartz from feldspar. Across the pH range of 3 to 11, DMB demonstrates high collection capability for quartz, but lower capability for feldspar. In particular, at pH levels of 7 to 8, the recovery difference between the two minerals exceeds 80%, achieving optimal selective separation. Mechanistic studies indicate that DMB primarily adsorbs on quartz and feldspar through electrostatic adsorption. The adsorption energy between DMB and quartz reaches −340.59 kJ/mol, forming a stable adsorption layer on the quartz surface. However, electrostatic repulsion arises over a broad area due to the large volume and cationic nature of DMB’s polar group and the exposed cationic Al sites on the feldspar surface, thereby hindering the interaction between DMB and feldspar. This research establishes the foundation for achieving efficient selective flotation separation of quartz and feldspar in a neutral system. Full article

In recent decades, there has been an upsurge in focus on the extraction of pyrite from sulfide ore deposits due to its vital role in the process of metal extraction and environmental management. This study explores the flotation behavior of pyrite in sulfide ores using mechanical-cell flotation. This study compared the performance of two commonly used flotation collectors, potassium butyl xanthate (KXT) and diethyl dithiophosphate (DTP), in the beneficiation of a sulfide ore from southwestern Spain. Statistical analysis performed using MiniTab 4.0 revealed that collector type, reagent dosage, and pulp pH were the principal factors affecting pyrite recovery. Under the tested conditions, KXT exhibited superior metallurgical performance and selectivity compared with DTP. The flotation kinetics demonstrate that the chemical was more efficacious throughout both the rougher and cleaner phases of the process. The findings robustly corroborate the notion that employing xanthate-based chemicals to enhance pyrite concentration facilitates metal extraction from the Sulfide Ore Deposit in southwestern Spain. The study sets out a basis for process growth, and it is proposed that further research be conducted under industrial water conditions to validate the findings. Full article

This study investigated the flotation performance of W8, a blended xanthate collector containing ethyl, butyl, propyl, and amyl xanthates, combined with ammonium dibutyl dithiophosphate (ADD) for treating low-grade arsenopyrite-type gold ore from Golmud, Qinghai. Real ore flotation tests demonstrated the superior efficacy of the W8 + ADD system, achieving 84.06% gold recovery with 0.34 g/t tailings, outperforming conventional sodium amyl xanthate (SAX) + ADD and sodium propyl xanthate (SPX) + ADD systems. Systematic studies on pure arsenopyrite revealed a significant synergistic effect in the mixed SPX-SAX system (1:4 ratio), representative of W8 composition. At pH 9, the mixed collector achieved 73.5% recovery, substantially higher than individual SPX (37.5%) or SAX (45.8%). This enhanced performance was attributed to improved surface hydrophobicity (contact angle 47.68° vs. 36.92° for SAX), greater adsorption density (4.97 × 10⁻⁷ mol/g under depressant conditions), and extensive formation of molecular aggregates observed via AFM, which increased surface roughness to 28.95 nm. Flotation kinetics further confirmed the advantage of W8 + ADD, which reached 72.1% cumulative recovery in 420 s, exceeding both mixed SPX/SAX (69.5%) and single SAX (65.5%) systems. The synergistic interaction among different xanthate components in W8 enables efficient recovery of gold from this refractory ore. Full article