Search Results (222)

To address the challenges of low KCl recovery and high collector consumption during flotation at low temperature, a novel approach with utilizing a compound collector consisting of octadecylamine hydrochloride (ODA) and alcohols (butanol, octanol, and dodecanol) to enhance low-temperature KCl flotation recovery was proposed in this study. The flotation performance and underlying mechanisms of this novel amine–alcohol compound collector were investigated through combination of micro-flotation tests, contact angle measurements, and molecular dynamics simulations. The results revealed that KCl flotation recovery decreased with declining temperature using single ODA as the collector, and the maximum KCl flotation recovery was approximately 40% with an ODA concentration of 1 × 10⁻⁵ mol/L at the temperature of 0 °C. Moreover, amine–alcohol compound collector shows different KCl flotation recovery; among them, dodecanol (DOD) presents the best performance at 25 °C with an ODA concentration of 3 × 10⁻⁶ mol/L. The KCl flotation recovery initially increased and then gradually decreased with increasing the DOD concentration, and 90% KCl recovery was achieved with a DOD concentration of 1.5 × 10⁻⁵ mol/L (DOD:ODA = 5:1 in mole) under 25 °C. Furthermore, this compound collector exhibited high selectivity for KCl/NaCl flotation. Mechanism studies indicated that the trend in contact angle changes on the KCl crystal surface closely mirrored the trend in flotation recovery. Molecular dynamics simulations demonstrated that at 0 °C, the presence of DOD resulted in a higher diffusion coefficient for ODA molecules compared to the system without DOD. Additionally, the water molecules in System 3 exhibited a lower diffusion coefficient and a greater number of hydrogen bonds. This novel compound collector offers a potential solution for improving KCl recovery and reducing ODA consumption during low-temperature flotation. It holds significant theoretical and practical implications for advancing low-temperature KCl flotation technology. Full article

This study investigates the beneficiation of finely grinded rutile ore utilizing a combination of flocculation and flotation methods. Rutile, a Ti-bearing mineral with industrial significance, is often associated with heavy minerals found in coastal and metamorphic environments. A rutile ore sample from Azıtepe (Alaşehir, Türkiye) was reduced to −63 µm and enriched under varying pH conditions (2.5–12) using different reagent combinations and was used for our investigation of both flocculation and flotation processes using reagents such as Aero801(SIPX), Aero825, tannic acid (TA), and pomace oil. The best results were achieved at pH: 8 using Aero801(SIPX) and pomace oil during flocculation, and Aero801(SIPX), Aero825, and Aerofroth88 during flotation, yielding a concentrate with an 8.99% TiO₂ grade and an 89.5% recovery rate. Meanwhile, a 7.00% TiO₂ grade concentrate was obtained with a recovery rate of 71.92% at neutral pH. This study found that pH and reagent selection had an important effect on TiO₂ enrichment efficiency in fine size, low-grade rutile ores. Future research is recommended to investigate selective depressants and multi-stage cleaning to improve separation. Full article

Wastewater generation is a growing concern in the preliminary treatment of heavy crude oil and tar sand. The separation of fine oil droplets from water by flotation is a critical process in the production of bitumen from tar sand. The flow structure from a high-resolution simulation of a single air macrobubble (>3 mm diameter) rising through water in the presence of a very dilute dispersion of mono-sized oil microdroplets (30 μm) under quiescent conditions is presented. A combined model of computational fluid dynamics (CFD), a volume of fluid (VOF) multiphase approach, and the discrete phase method (DPM) was developed to simulate bubble dynamics, the trajectories of the dispersed oil droplet, and the interaction between the air bubble and the oil droplet in quiescent water. The CFD–VOF–DPM combined model reproduced the interacting dynamics of the bubble and oil droplets in water at the bubble–droplet scale. With an extremely large diameter ratio between the bubble and the dispersed oil droplet, this model clearly demonstrated that the dominant mechanism for the interaction was the hydrodynamic capture of oil droplets in the wake of a rising air macrobubble. The entrainment of the oil droplets into the wake of the rising bubbles was strongly influenced by the bubble’s shape. Full article

Maximizing the efficient utilization of critical apatite resources through flotation necessitates the exploration of effective and innovative collectors. This study investigates the potential of a fatty acid mixture (FAM) synthesized from saturated palmitic and stearic acids, monounsaturated oleic and palmitoleic acids, and polyunsaturated linoleic acid. The saponified collector FAM and the depressant sodium alginate (NaAl) achieved a direct flotation of apatite from calcite and quartz (97% apatite, 10% calcite, and 7% quartz). The flotation performance with the tested combination exhibited a highly effective enrichment of apatite, mainly from calcite, which aligns with the surface chemistry assessments. Adsorption tests and zeta potential measurements confirmed the micro-flotation results. They provided compelling evidence of a chemisorption interaction between Ca²⁺ sites on calcite and the carboxyl and hydroxyl groups of NaAl. FTIR analyses suggested a reaction between the apatite surface and the carboxyl groups of saturated and unsaturated acid groups in FAM, even those conditioned with NaAl before, facilitating the complex formation. Remarkably, the synergistic effect of the functional groups demonstrates dual functionality, serving as both a hydrophilic entity for calcite and a hydrophobic entity for apatite flotation. The universal mechanism unveils substantial potential for the extensive application of FAM within apatite flotation. Full article

High-gradient magnetic separation is a key step in the pre-concentration of ilmenite before flotation, particularly in the gravity separation process. However, as the amount of weakly magnetic gangue minerals increases, the grade of the coarse concentrate from high-gradient magnetic separation decreases. This paper investigates the mineralogical factors affecting the enrichment efficiency of high-gradient magnetic separation. Additionally, a newly developed stirred fluidized bed device, an agitated reflux classifier (ARC), was successfully applied to remove weakly magnetic gangue minerals that are difficult to separate by high-gradient magnetic separation (HGMS). For low-grade ilmenite with a feed grade of 3.97%, a combined process of magnetic separation and gravity separation was employed, achieving a concentrate with a grade of 16.50% and a recovery rate of 54.11%. This concentrate meets the requirements for flotation feed. This study provides a new approach for the beneficiation of low-grade ilmenite. Full article

A series of homologous saturated fatty acids were introduced and evaluated as collectors for ilmenite flotation using a combination of micro-flotation tests and surface tension measurements. The results showed that ilmenite exhibited good flotation behaviour when decanoic and dodecanoic acids were used as collectors; however, saturated fatty acids with shorter or longer carbon chains were not suitable for ilmenite flotation (caused either by poor collection ability or limited solubility in water). The optimum flotation pH range was also dependent on the carbon chain length of saturated fatty acids, and the solution surface tension did not always match well with the ilmenite flotation behaviour when using a series of saturated fatty acids as the collector. The associated solution chemistry properties under series saturated fatty acid flotation systems were discussed, and the adsorption mechanism of decanoic acid onto the ilmenite surface was also investigated via FTIR, zeta potential, and contact angle measurements. Full article

Phonolite is a fine-grained, shallow extrusive rock rich in alkali minerals and containing iron/titanium-bearing minerals. This rock is widely used as a construction material for building exteriors due to its excellent abrasion resistance and insulation properties. However, during the cutting process, approximately 70% of the rock is discarded as tailing. So, this study aims to repurpose tailings from a phonolite cutting and sizing plant into a high-alkali ceramic raw mineral concentrate. To enable the use of phonolite tailings in ceramic manufacturing, it is necessary to remove coloring iron/titanium-bearing minerals, which negatively affect the final product. To achieve this removal, dry/wet magnetic separation processes, along with flotation, were employed both individually and in combination. The results demonstrated that using dry high-intensity magnetic separation (DHIMS) resulted in a concentrate with an Fe₂O₃ + TiO₂ grade of 0.95% and a removal efficiency of 85%. The wet high-intensity magnetic separation (WHIMS) process reduced the Fe₂O₃ + TiO₂ grade of the concentrate to 1.2%, with 70% removal efficiency. During flotation tests, both pH levels and collector concentration impacted the efficiency and Fe₂O₃ + TiO₂ grade (%) of the concentrate. The lowest Fe₂O₃ + TiO₂ grade of 1.65% was achieved at a pH level of 10 with a collector concentration of 2000 g/t. Flotation concentrates processed with DHIMS achieved a minimum Fe₂O₃ + TiO₂ grade of 0.90%, while those processed with WHIMS exhibited higher Fe₂O₃ + TiO₂ grades (>1.1%) and higher recovery rates (80%). Additionally, studies on flotation applied to WHIMS concentrates showed that collector concentration, pulp density, and conditioning time significantly influenced the Fe₂O₃ + TiO₂ grade of the final concentrate. Full article

The prevention of bubble coalescence is essential in various industrial processes, such as mineral flotation, where the stability of air–liquid interfaces significantly affects performance. The combined influence of multiple physicochemical parameters on bubble coalescence remains insufficiently understood, particularly under conditions relevant to flotation. This study explores the key factors that influence the inhibition of bubble coalescence in aqueous solutions containing methyl isobutyl carbinol (MIBC), providing a systematic comparative analysis to assess the effect of each variable on coalescence inhibition. An experimental method was employed in which two air bubbles were formed from identical capillaries and brought into contact either head-to-head or side-by-side, then held until coalescence occurred. This setup allows for reliable measurements of coalescence time with minimal variability regarding the conditions under which the bubbles interact. The study examined the effects of several factors: temperature, pH, salt concentration and type, bubble approach speed, contact area, and contact configuration. The results reveal that coalescence is delayed at lower temperatures, alkaline pH conditions, high salt concentrations, and larger interfacial contact areas between bubbles. Within the range studied, the influence of approach speed was found to be insignificant. These findings provide valuable insights into the fundamental mechanisms governing bubble coalescence and offer practical guidance for optimizing industrial processes that rely on the controlled stabilization of air–liquid interfaces. By understanding and manipulating the factors that inhibit coalescence, it is possible to design more efficient and sustainable mineral flotation systems, thereby reducing environmental impact and conserving water resources. Full article

Anoplocephala spp. are common equine tapeworm species in Europe, frequently found in grazing horses. Anoplocephala perfoliata is the most pathogenic, clinically significant species associated with gastrointestinal disorders, particularly colic, and can have a fatal outcome in some horses. The aim of this study was to determine the infection prevalence of Anoplocephala spp. in Serbia and to identify relevant risk factors. A total of 173 horses from various regions were tested using a combination of diagnostic methods: coprological analysis via combined sedimentation–flotation and the Mini-FLOTAC technique, as well as serological testing using a commercial ELISA test. The overall prevalence was 38.7%, with a higher number of positive cases being identified by serology. It was demonstrated that coprology and serology are complementary approaches for prevalence studies. Infection risk factors included high stocking density, free-roaming status and co-infection with nematodes, while lower rainfall and temperate climate were associated with reduced risk of tapeworm infection. These findings highlight the challenges of Anoplocephala spp. detection and provide insight into the epidemiology of equine tapeworm infection in Southeastern Europe. Full article

A methodology for detecting systematic errors in sets of equally accurate, uncorrelated, aggregate measurements is proposed and applied within the automatic real-time dispatch control system of a copper concentrator plant (CCP) to refine the technical and economic performance indicators (EPIs) computed by the system. This work addresses and solves the problem of selecting and obtaining reliable measurement data by exploiting the redundant measurements of process streams together with the balance equations linking those streams. This study formulates an approach for integrating cloud technologies, machine learning methods, and forecasting into information control systems (ICSs) via predictive analytics to optimize CCP production processes. A method for combining the hybrid cloud infrastructure with an LSTM-DNN neural network model has been developed, yielding a marked improvement in TEP for copper concentration operations. The forecasting accuracy for the key process parameters rose from 75% to 95%. Predictive control reduced energy consumption by 10% through more efficient resource use, while the copper losses to tailings fell by 15–20% thanks to optimized reagent dosing and the stabilization of the flotation process. Equipment failure prediction cut the amount of unplanned downtime by 30%. As a result, the control system became adaptive, automatically correcting the parameters in real time and lessening the reliance on operator decisions. The architectural model of an ICS for metallurgical production based on the hybrid cloud and the LSTM-DNN model was devised to enhance forecasting accuracy and optimize the EPIs of the CCP. The proposed model was experimentally evaluated against alternative neural network architectures (DNN, GRU, Transformer, and Hybrid_NN_TD_AIST). The results demonstrated the superiority of the LSTM-DNN in forecasting accuracy (92.4%), noise robustness (0.89), and a minimal root-mean-square error (RMSE = 0.079). The model shows a strong capability to handle multidimensional, non-stationary time series and to perform adaptive measurement correction in real time. Full article

Electrocoagulation is rapidly gaining prominence in wastewater treatment due to its capabilities and less reliance on additional chemicals. While a lot of research efforts have been focused on the influence of the anode material, power supply, and reactor design, the contribution of the cathode to contaminant removal has been less explored. In this study, we investigated the performance of stainless steel (SS-304) and aluminium (Al-6061) electrodes in both similar and dissimilar configurations for a 120 min electrocoagulation treatment of spent machinery coolant. The anode–cathode configurations, including SS-SS, Al-Al, SS-Al and Al-SS, have been investigated. Additionally, we examined the effects of the initial pH and agitation methods on the process performance. Our findings indicated that the type of cathode could significantly affect the floc formation and contaminant removal. Notably, the combination of an Al anode and SS cathode (Al(A)-SS(C)) demonstrated a synergistic improvement in the Chemical Oxygen Demand (COD), with a removal of 84.3% within a short treatment time (<20 min). The final COD removal of 91.4% was achieved with a turbidity level close to 12 Nephelometric Turbidity Units (NTU). The Al anode readily released the Al ions and formed light flocs at the early stage of electrocoagulation, while the SS cathode generated heavy Fe hydroxides that mitigated the flotation effect. These results demonstrated the cathode’s significant contribution in electrocoagulation, leading to potential savings in the treatment time required. Full article

As a critical mineral, magnesite plays a vital role in industries such as steelmaking, construction, and advanced technologies due to its high thermal stability and chemical resistance. However, the beneficiation of low-grade magnesite ores (~38.36% MgO) remains challenging due to the presence of iron, silica, and calcium-bearing impurities. This study proposes an integrated beneficiation strategy combining medium-intensity magnetic separation and flotation techniques to upgrade a low-grade magnesite ore. After grinding to 75 µm (d₈₀), the sample was subjected to two-stage magnetic separation at 5000 Gauss to remove Fe-bearing minerals, reducing Fe₂O₃ below 0.5%. The non-magnetic fraction was then treated through a two-stage reverse flotation process using dodecylamine (350 g/t) and diesel oil (60 g/t) at pH 7 to reject silicate gangue. This was followed by a four-stage direct flotation using sodium oleate (250 g/t), sodium silicate (350 g/t), and SHMP (100 g/t) at pH 10 to selectively recover magnesite while suppressing Ca-bearing minerals. The optimized flowsheet achieved a final concentrate with MgO > 46.5%, SiO₂ ≈ 1.05%, Fe₂O₃ ≈ 0.44%, and CaO ≈ 0.73%, meeting the specifications for refractory-grade magnesite. These results highlight the effectiveness of a combined magnetic–flotation route in upgrading complex, low-grade magnesite deposits for commercial use. Full article

The co-occurring relationships between ilmenite and gangue minerals in ilmenite deposits, as well as fine mineral embedding particle sizes, are complex. During the beneficiation process, grinding ilmenite finely is necessary to achieve sufficient individual mineral dissociation and the efficient recovery of ilmenite. During this process, a large number of fine-grained minerals can easily be generated, which adversely affects flotation separation. Micro–nanobubbles have been proven to effectively enhance the flotation separation efficiency of fine-grained minerals, as their cavitation characteristics are closely related to the flotation performance of the minerals. In order to fully understand the cavitation characteristics of micro–nanobubbles and their impact on the flotation recovery of fine-grained ilmenite, a series of experiments were conducted using methods such as the bubble cavitation property test, micro-flotation experiments, zeta potential analysis, the contact angle test, adsorption capacity detection, and PBM monitoring. The results indicate that during the process of slurry cavitation, appropriate concentrations of 2-octanol, cycle treatment times, and external inflation volume are conducive to the formation of micro–nanobubbles. Compared with deionized water without cavitation, cavitated micro–nanobubble water is more beneficial for the flotation separation of fine particulate ilmenite, titanaugite, and olivine. The presence of micro–nanobubbles can effectively promote the adsorption of combined collectors on mineral surfaces, significantly enhancing the hydrophobicity of the minerals, with an even stronger promoting effect observed under the treatment of 2-octanol. Micro–nanobubbles can adsorb a portion of the collectors originally attached to the mineral surfaces, thereby decreasing the absolute value of the surface potential of the minerals, which is beneficial for mineral aggregation. The introduction of micro–nanobubbles promotes the aggregation of fine ilmenite iron ore particles into flocculent bodies. 2-Octanol can reduce the size of the micro–nanobubbles generated during the cavitation process of the mineral slurry and, to a certain extent, weaken the phenomenon of bubble coalescence, so they demonstrate a greater advantage in facilitating the aggregation phenomenon. Full article

Semicrystalline polystyrene spheroidal nanoparticles (50–100 nm) were obtained via microemulsion polymerization. They were evaluated as coal collectors in a low-rank carbonaceous mineral containing 2% organic carbon. The recovery of coal using nanoparticles as collectors was 88.2%, in contrast to 53.2%, 46.4%, and 44.8% achieved using an amine-type compound, kerosene, and diesel, respectively. X-ray photoelectron spectroscopy (XPS) and zeta potential measurements confirmed the polystyrene–mineral surface chemical interaction. A Box–Behnken experimental design for flotation optimization was applied, and the results showed that the coal recovery increased up to 99.5% when the dosage of the collector was increased. A contact angle study and density functional theory calculations, together with XPS results, allowed us to postulate an interaction mechanism in which polystyrene nanoparticles adsorb onto the coal surface through hydrophobic interactions, rendering the oxidized surface hydrophobic and the coal buoyant by adhering to the gas bubbles. Full article

Selective separation of gold-bearing pyrite from gold-free pyrite through flotation to improve the gold-to-sulfur ratio in the feed can significantly enhance the throughput of autoclaves, thus achieving efficient and clean processing of refractory pyritic gold ores. To achieve this expectation, this study examined the surface physicochemical differences between gold-bearing and gold-free pyrite under flotation conditions using cyclic voltammetry, polarization curve testing, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) simulations. Electrochemical tests showed higher reactivity in gold-bearing pyrite, with reactivity positively correlated to gold content. XPS results indicated more oxidation products on gold-bearing pyrite surfaces under identical conditions. DFT simulations revealed that the presence of gold reduced the oxygen adsorption energy on the pyrite surface while enhancing interactions between oxygen atoms and sulfur and iron atoms. Based on these findings, the selective separation of gold-bearing and gold-free pyrite in the flotation process can be explored through pulp aeration pre-oxidation combined with collectors demonstrating selectivity toward barren pyrite (e.g., dithiocarbamate collectors). This study provides theoretical foundations for the efficient exploitation and utilization of refractory gold-bearing pyrite resources. Full article