Magnetic Separation Research Articles

Optimizing Electrocoagulation for Polystyrene Microplastics Removal via Magnetic Separation

Optimizing Electrocoagulation for Polystyrene Microplastics Removal via Magnetic Separation

Iron extraction from dust from scrap metal smelting in electric arc furnaces by magnetic separation

Iron extraction from dust from scrap metal smelting in electric arc furnaces by magnetic separation

Investigation of the effect of mineral composition and size on particle separation in Wet low and high intensities magnetic separators: An industrial case

Magnetic separation is used in ore processing to separate the minerals according to their magnetic susceptibility. Particle size also plays a role in the separation although few industrial results are presented in the literature to discuss this matter. Results from sampling industrial Wet Low Intensity Magnetic Separators (WLIMS) and Wet High Intensity Magnetic Separators (WHIMS) for processing an iron ore show that except for the strongly paramagnetic magnetite (Fe3O4), the recovery of minerals decreases with increasing particle size for both WLIMS and WHIMS. The examination of polished sections of the coarse size fractions from the reject streams of the WHIMS does not provide ground to suspect liberation to be responsible for the reduced recovery of coarse particles. Results also show that it is difficult to establish clear relationships between the mineral recoveries and their reported magnetic susceptibilities for WLIMS while for WHIMS a weak trend is observable.

Removal of Germanium from a Solution by a Magnetic Iron-Based Precipitant.

This study presents a method for the precipitation of germanium from a solution using magnetic iron-based precipitants and contrasts this method with the commonly employed neutralization-precipitation technique in industrial production, analyzing and comparing their reaction conditions and the properties of their precipitates. This study analyzes the influence of varying experimental conditions (reaction time, reaction temperature, iron:germanium molar ratio, Fe3+:Fe2+ molar ratio, and reaction pH) on the germanium precipitation efficiency. With a precipitation time of 30 min, a precipitation temperature of 30 °C, an iron:germanium molar ratio of 30:1, an Fe3+:Fe2+ molar ratio of 3:1, and a reaction pH of 5.0, the optimal germanium precipitation efficiency achieved was 99.5%. Furthermore, this study employed X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry to analyze the properties and composition of the precipitate, providing support for the conclusion regarding germanium precipitation using magnetic iron-based precipitants. Through theoretical analysis and instrumental testing, it was determined that the precipitation of germanium from a solution using magnetic iron-based precipitants significantly reduces the reaction time compared to those of neutralization-precipitation methods. Moreover, a magnetic iron-based precipitant substantially reduces the amount of precipitate, allows for magnetic separation of the precipitate, and effectively alleviates the problem of the presence of other valuable metals in the precipitate.

Strand displacement amplification combining photothermal-colorimetric dual mode test strip for ultra-sensitive detection of patulin

Patulin (PAT) is a fungal toxin often found in fruit and juice products. The sensitive and fast detection of PAT can help the control of PAT-induced health risk. However, the lack of efficient and stable antibody for PAT hindered the advancement of its test strips. Here, we constructed a nucleic acid-based lateral flow test strip (NALFTS) and used photothermal-colorimetric dual mode for the detection of PAT. The binding of PAT in samples to the aptamer on magnetic separation probe MNPs-Apt@cDNA induced the release of cDNA competitively. Subsequently, cDNA initiates strand displacement amplification (SDA), generating numerous single-strand DNA (ssDNA). These ssDNA molecules were analyzed by a test strip with photothermal-colorimetric dual signal. The developed method demonstrated a limit of detection (LOD) of 5 pg mL−1 and a quantitative range of 0.01 ∼ 320 ng mL−1 in photothermal mode, and a LOD of 0.1 ng mL−1 and a quantitative range of 0.1 ∼ 40 ng mL−1 in colorimetric mode. This SDA-NALFTS offered dual signals corroborating each other to provide more reliable results for rapid screening or accurate monitoring of PAT in juice.

Chitosan-coated manganese ferrite nanoparticles enhanced Rhodotorula toruloides carotenoid production.

The present study aims to analyze the interaction between Rhodotorula toruloides and magnetic nanoparticles and evaluate their effect on carotenoid production. The manganese ferrite nanoparticles were synthesized without chitosan (MnFe2O4) and chitosan coating (MnFe2O4-CS) by the co-precipitation method assisted by hydrothermal treatment. XRD (X-ray diffraction), Magnetometry, Dynamic Light Scattering (DLS) and FTIR (Fourier-Transform Infrared Spectroscopy), are used to characterize the magnetic nanoparticles. The crystallite size of MnFe2O4 was 16 nm for MnFe2O4 and 20 nm for MnFe2O4-CS. The magnetic saturation of MnFe2O4-CS was lower (39.6 ± 0.6 emu/g) than the same MnFe2O4 nanoparticles (42.7 ± 0.3 emu/g), which was attributed to the chitosan fraction presence. The MnFe2O4-CS FTIR spectra revealed the presence of the characteristic chitosan bands. DLS demonstrated that the average hydrodynamic diameters were 344 nm for MnFe2O4 and 167 nm for MnFe2O4-CS. A kinetic study of cell immobilization performed with their precipitation with a magnet demonstrated that interaction between magnetic nanoparticles and R. toruloides was characterized by an equilibrium time of 2h. The adsorption isotherm models (Langmuir and Freundlich) were fitted to the experimental values. The trypan blue assay was used for cell viability assessment. The carotenoid production increased to 256.2 ± 6.1 µg/g dry mass at 2.0 mg/mL MnFe2O4-CS. The use of MnFe2O4-CS to stimulate carotenoid yeast production and the magnetic separation of biomass are promising nanobiotechnological alternatives. Magnetic cell immobilization is a perspective technique for obtaining cell metabolites.

Novel Carbon@BaMoZrFe12O19 photocatalytic peroxymonosulfate activation for ibuprofen removal

This study reports a successful synthesis of a novel Carbon@BaMoZrFe12O19 M-hexaferrite photocatalyst (NPs) using the coprecipitation method. Afterthat, the NPs were used as an activator for peroxymonosulfate (PMS) to remove ibuprofen (IBU) from water. NPs were subjected for a thorough characterization process utilizing various analytical techniques including XRD, FTIR, UV, PL TEM, SEM/EDS, and X-ray photoelectron spectroscopy (XPS). Significantly, the utilization of NPs for PMS activation demonstrated a notable improvement in the elimination of IBU under visible light. The research conducted a thorough investigation into the effects of various parameters, such as activating systems, initial pH, inorganic salts, IBU contents, and water matrix on the efficiency of IBU degradation. The significance of reactive oxygen species, such as sulfate and hydroxyl radicals, as well as singlet oxygen, in the removal of IBU, was clarified by chemical quenching tests. In addition, NPs exhibited competent magnetic separation and reprocessing capacities. The magnetic NPs revealed excellent constancy and recyclability, by sustaining degrading productivity after five consecutive cycles. Therefore, the present study offers a significant contributions to the understanding of photocatalytic degradation for organic pollutants through the utilization of magnetic photocatalysts.

Green and Mild Fabrication of Magnetic Poly(trithiocyanuric acid) Polymers for Rapid and Selective Separation of Mercury(II) Ions in Aqueous Samples

The removal and detection of highly toxic mercury(II) ions (Hg2+) in water used daily is essential for human health and monitoring environmental pollution. Efficient porous organic polymers (POPs) can provide a strong adsorption capacity toward heavy metal ions, although the complex synthetic process and inconvenient phase separation steps limit their application. Hence, a combination of POPs and magnetic nanomaterials was proposed and a new magnetic porous organic polymer adsorbent was fabricated by a green and mild redox reaction in the aqueous phase with trithiocyanuric acid (TA) and its sodium salts acting as reductive monomers and iodine acting as an oxidant. In the preparation steps, no additional harmful organic solvent is required and the byproducts of sodium iodine are generally considered to be non-toxic. The resulting magnetic poly(trithiocyanuric acid) polymers (MPTAPs) are highly porous, have large surface areas, are rich in sulfhydryl groups and show easy magnetic separation ability. The experimental results show that MPTAPs exhibit good adsorption affinity toward Hg2+ with high selectivity, rapid adsorption kinetics (10 min), a large adsorption capacity (211 mg g−1) and wide adsorption applicability under various pH environments (pH 2~8). Additionally, MPTAPs can be reused for up to 10 cycles, and the magnetic separation step of MPTAPs is fast and convenient, reducing energy consumption compared to centrifugation and filtration steps required for non-magnetic adsorbents. These results demonstrate the promising capability of MPTAPs as superior adsorbents for effective adsorption and separation of Hg2+. Based on this, the prepared MPTAPs were adopted as magnetic solid-phase extraction (MSPE) materials for isolation of trace Hg2+ from aqueous samples. Under optimized conditions, the extraction and quantification of trace Hg2+ in water samples were accomplished using inductively coupled plasma mass spectrometry (ICP-MS) detection after MSPE procedures. The proposed MPTAPs-based MSPE-ICP-MS method is efficient, rapid, sensitive and selective for the determination of trace Hg2+, and was successfully employed for the accurate analysis of trace Hg2+ in tap water, wastewater, lake water and river water samples.

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.

Effect of Na<sub>2</sub>CO<sub>3</sub> and CaCO<sub>3</sub> on deep dephosphorization by the direct reduction of high-phosphorus oolitic hematite

The direct reduction–magnetic separation process based on coal is considered to be one of the most important methods that can effectively utilize high-phosphorus oolitic hematite. In this study, the mechanism of the effects of CaCO<sub>3</sub> and Na<sub>2</sub>CO<sub>3</sub> on the dephosphorization of high-phosphorus oolitic hematite during the direct reduction process was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that Na2CO3 and CaCO3 reacted with Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> during the direct reduction process, inhibited the generation of hercunite (FeAl<sub>2</sub>O<sub>4</sub>) and fayalite (Fe<sub>2</sub>SiO<sub>4</sub>), and promoted the reduction of metallic iron (Fe). Furthermore, the reaction inhibited the reduction of apatite and prevented the generation of FeP<sub>2</sub>. Na<sub>2</sub>CO<sub>3</sub> could change the form of phosphorus in the gangue from Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> to Na<sub>2</sub>Ca<sub>4</sub>(PO<sub>4</sub>)<sub>2</sub>SiO<sub>4</sub>. Increasing the dosages of Na2CO3 and CaCO3 in the dephosphorization agent and increasing the content of Na<sub>2</sub>CO<sub>3</sub> in the dephosphorization agent were beneficial to the growth of metallic iron particles, and increasing the dosage of Na<sub>2</sub>CO<sub>3</sub>, CaCO<sub>3</sub> in the dephosphorization agent had more significant effects on metallic iron particles than increasing the content of Na<sub>2</sub>CO<sub>3</sub> in the dephosphorization agent. The research conducted in this study is expected to provide a basis for the effective exploitation of complex and refractory iron ores.

Polyoxometalate Derived Materials as Laccase‐Mimic Nanozyme and Reduction Catalyst for p‐Nitrophenol Remediation in Water

Abstractp‐Nitrophenol (PNP), a highly toxic water pollutant, poses significant risks to human health and the environment. For detecting PNP, a colorimetric method utilizing a nanozyme that mimics laccase activity presents a viable approach. In this study, PV14@MIL‐88A, a robust nanozyme with superior laccase‐mimic capabilities, was synthesized by incorporating Na7H2[PV14O42] (PV14) into MIL‐88A, a metal‐organic framework (MOF). This nanozyme demonstrates optimal laccase‐mimicking activity, enabling effective PNP detection via colorimetry and digital image colorimetry using smartphones. Theoretical analyses suggest that the outstanding laccase‐mimic activity of PV14@MIL‐88A is derived from the optimized d‐band center in PV14. Upon calcination with dicyandiamide (DCDA), PV14@MIL‐88A transforms into Fe2O3/VO2@NCNF. In the presence of NaBH4, Fe2O3/VO2@NCNF facilitates the conversion of PNP to p‐aminophenol (PAP), an essential precursor in paracetamol synthesis. The interaction between Fe2O3 and VO2 in Fe2O3/VO2@NCNF enhances adsorption and subsequent reduction of PNP. The saturation magnetization of Fe2O3/VO2@NCNF reaches 25 emu g−1, which supports efficient magnetic separation in the reduction process. This study not only advances an effective method for PNP detection but also facilitates its transformation from a hazardous pollutant into a valuable chemical precursor.

Recovery of Xenotime and Florencite from Silicate Minerals Using a Combined Technique of Magnetic Separation and Flotation

Xenotime (YPO4), a significant phosphatic minerl rich in heavy rare earth elements (HREEs), typically associates with granitic rocks, exemplified in the Wolverine rare earth deposit in Australia. A mineral composition analysis indicates that the primary valuable minerals in the deposit are principally xenotime and minor florencite, with quartz and illite as the main gangue minerals, showing a relatively simple mineral composition. The grade of rare earth concentrate was increased to 14.29% and the recovery reached 94.48% through the magnetic separation pre-enrichment test. However, a high-grade rare earth concentrate could not be achieved using magnetic separation alone. Further purification of the magnetic concentrate is conducted through flotation. The grade of rare earth concentrate reached 51.26%, and the recovery rate reached 90.47%. In summary, this process achieves the efficient recovery of xenotime and florencite, having substantial industrial potential.

Features of proinflammatory activation of macrophages in patients with rheumatoid arthritis and systemic lupus erythematosus

Autoimmune rheumatic diseases (ARDs) are chronic pathological conditions that arise from an abnormal immune response and are accompanied by systemic inflammation. The most common ARDs include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). The exact pathogenesis of ARDs remains unclear, but the complex influence of genetic, immunological and external environmental factors leads to the occurrence and further progression of ARDs. It has been shown that the cause of chronic inflammation may be proinflammatory activation of macrophages, in which an increase in the secretion of cytokines is observed. The aim of this study was to evaluate the inflammatory response of macrophages in patients with RA, SLE and SSc. Materials and methods. The study included 143 participants: 47 patients with RA, 45 patients with SLE, 34 patients with SSc, and 17 people without ARDs and other chronic diseases. Isolation of a primary culture of monocytes was carried out by centrifugation in a ficoll gradient using magnetic separation from the whole blood of study participants. Lipopolysaccharide (LPS) was added to stimulate cells along the proinflammatory pathway. Cell cultivation was carried out for 24 hours. Determination of basal and LPS-stimulated secretion of IL-8 by macrophages was carried out in the culture fluid using an enzyme-linked immunosorbent assay (ELISA). Proinflammatory activation of macrophages was calculated as the ratio of LPS-stimulated and basal IL-8 secretion. Research results. Basal secretion of IL-8 by macrophages was statistically significantly higher in the groups of patients with RA and SSc compared with the SLE and control groups. LPS-stimulated secretion of IL-8 by macrophages in the SSc group had statistically higher values compared to the RA and SLE groups. Proinflammatory activation of macrophages was reduced in the group of patients with RA compared to patients with SLE and the control group, and was also statistically significantly lower in patients with SSc compared to the control group.

Study on the influence of high permeability magnetic iron on energy consumption reduction in high gradient magnetic separator

The green processing of weakly magnetic iron ore is inseparable from high-intensity and high-gradient magnetic separator (HGMS), which is one of the most energy-intensive magnetic separation equipment. Iron (Fe) armor serves as the key primary structure for enhancing magnetic field conduction efficiency within the magnetic system. The order of magnetic properties of commonly used magnetic yoke materials is: ordinary carbon structural steel < Q235 steel < DT4 electrical pure iron. But the utilization cost of DT4 electrical pure iron is the highest, especially the magnetic properties of DT4C super electrical pure iron are unstable and the yield is low. On the basis of ordinary pure iron materials, this article has developed a new type of 411 pure iron (411) upon controlling the levels of harmful elements, while increasing the concentration of beneficial elements.intensity Furthermore, through the utilization of magnetic field simulation software, the impact of 411 on the background magnetic field intensity of HGMS was analyzed. The results indicated that the newly developed 411 pure Fe exhibited a coercivity of 24.07 A/m, a saturation magnetization intensity of ∼ 1.69 T, a maximum relative magnetic permeability of 24.38 × 10-3H/m, demonstrating superior magnetic properties in comparison with Q235 and DT4C. When using 411 pure iron as the magnetic yoke material, the background magnetic field intensity of the HGMS can be increased by 6.85 % − 14.64 % compared with using DT4C super pure iron under the same excitation current conditions. The magnetic yoke with better magnetic conductivity will enhance the magnetic field utilization efficiency of the magnetic system, a reduce the excitation energy consumption, and improve the sorting performance of HGMS.

A Novel Technology for the Recovery and Separation of Cassiterite- and Iron-Containing Minerals from Tin-Containing Tailing

Tin-containing tailing is classified as a solid waste, but it possesses valuable resources such as tin and iron. Tin-containing tailing exhibits a fine distribution and compact symbiosis of cassiterite- and iron-containing minerals. Therefore, it is difficult to recover and separate cassiterite- and iron-containing minerals using traditional mineral processing methods. The study proposed a novel technology involving pre-concentration, reduction roasting, and magnetic separation for the treatment of tin-containing tailings with a tin grade of 0.14% and an iron grade of 12.79%. The classification pre-concentration method was achieved using a combination of shaking tables, suspension vibration cone separators, and high-gradient magnetic separation with a magnetic field strength of 1.4 T. The discarded tailings ratio reached 73.56%. The gravity pre-enriched concentrates and magnetic pre-enriched concentrates underwent reduction roasting to facilitate the conversion of hematite and goethite into magnetite, respectively. The optimal conditions for reduction roasting of the gravity pre-enriched concentrate were a 10% lignite dosage, a roasting temperature of 650 °C, and a holding time of 80 min. The optimal conditions for reduction roasting of the magnetic pre-enriched concentrate were a 8% lignite dosage, a roasting temperature of 750 °C, and a holding time of 100 min. The reduction roasted products were treated using magnetic separation with a magnetic field strength of 0.16 T. Finally, a tin-rich middling with a tin grade of 2.93% and a recovery ratio of 70.88%, as well as an iron concentrate with an iron grade of 61.95% and a recovery ratio of 68.08% were obtained. The study achieved efficient recoveries of tin and iron from tin tailings, thereby presenting a novel approach for the utilization of resources in the tailing.

შქმერის საბადო/მადანგამოვლინების გლაუკონიტიანი ქვიშების კვლევა გამდიდრებადობაზე

The article presents the results of studying the enrichment of glauconite sands of the Shkmeri deposit, taking into account the material composition and textural-structural features of the sample, the enrichment technology provides for washing/deslimation of the initial sample and magnetic separation of the sandy fraction. The developed enrichment technological scheme makes it possible to obtain 270 kg of concentrate with iron oxide content of 16% from 1 ton of ore.

A clenbuterol detection method based on magnetic separation up-conversion fluorescent probe

In this study, a fluorescence detection method combining aptamer-modified up-conversion nanoparticles (UCNPs) and magnetic nanoparticles (MNPs) was developed for detection of Clenbuterol (CLB). The aptamer-modified magnetic NPs captured CLB, which reacted with the aptamer-modified UCNPs and generated a sandwich complex. The aptamer-modified UCNPs acted as a fluorescence source. The MNP-CLB-UCNP complex was retrieved from the solution using an magnetic field, and the fluorescence intensity was detected by fluorescence spectrophotometry with excitation and emission spectra at 980 nm and in the 400–800 nm region, respectively. The results showed that the fluorescence intensity gradually increased with increasing concentrations of CLB with a good specify. The method was highly sensitive for the quantification of CLB, with a limit of detection of 0.304 ng mL−1. The recovery rate of CLB from pork samples ranged from 84 % to 94.87 %. This fluorescence method enables the sensitive, precise, and accurate quantification of CLB residues in pork samples.

Separation of iron and carbon concentrates from thermal power plant solid waste using physical methods

This research study examined the physical enrichment processes of coal fly ash (CFA) from the 2nd thermal power plant in Almaty. Magnetic separator and flotation enrichment methods were used to separate the magnetite and carbon parts of coal fly ash, respectively. In the study, a laboratory magnetic separator separated hematite content from 4.49 to 5.57% by mass from ash residues of different fractions. Cheap and available kerosene and flotol-b were used as flotation reagents for flotation enrichment. The particle size of coal ash is 63-100 μm, and the amount of carbon concentrate is ~16.3% by weight. The remaining mineral of coal ash is an essential raw material for building materials.

Judicious combinations of gravity, magnetic, electrostatic separators and microwave heat energy on recovery of ilmenite from Humma lean grade beach placer deposit

Microwave heating is an eco-friendly and novel technique for sintering and heating minerals and materials as it has several advantages in terms of phase transformation, energy efficiency, enhancing speed, process simplicity, improved properties. Such heating provides the composite materials to absorb electromagnetic energy volumetrically and transform into heat and produces larger densities as compared to conventional heating. This study focuses on two main objectives: the recovery of ilmenite through a strategic combination of mineral processing equipment, including a spiral concentrator, followed by magnetic and electrostatic separation, and the enhancement of ilmenite concentrate using microwave heat energy on a cleaner magnetic product, followed by electrostatic separation. Continuous magnetic separation results indicate that among the dry high-intensity belt magnetic separator, box mag wet high-intensity magnetic separator and dry rare earth drum magnetic separators, the rare earth magnetic separator yielded the highest quality product. The application of microwave heat energy before the rare earth drum magnetic separator at 1.4 T, followed by high-tension separation, produced the best grade of ilmenite. The magnetic product obtained after microwave treatment contained 98.6% ilmenite, which was further upgraded to a 99.6% ilmenite concentrate through high-tension separation. Therefore, it is recommended that an effective combination of gravity separation, microwave heat energy, rare earth drum dry magnetic separation and high-tension separation be employed to achieve the highest grade of ilmenite concentrate.

Internal-driven DNA nanowindmill: Multi-fulcrum mediated amplified rolling nanomachine for fast and ultrasensitive electrochemical detection of tau

Inspired by the wind driving windmill rolling to generate electrical energy, we have fabricated a multi-fulcrum mediated amplified rolling nanomachine (MFN) for Tau detection with the internal drive. The MFN backbone is DNA nanowindmill (DM) self-assembled from DNA, which is initially ineffective and finally activated into an effective DM through interaction with Tau followed by the magnetic separation. The DM is introduced to the electrode interface where it continues rolling under the drive of the multi-fulcrum and signal probe to achieve signal amplification. On one hand, the modular design and DM rolling feeds the impediment of signal transduction and amplification due to spatial hindrance during protein detection. On the other hand, it endows fast response and high sensitivity. The proposed MFN electrochemical biosensor is successfully applied to detect Tau ranging from 10 pg/mL to 2 μg/mL with low detection limit of 127 fg/mL, which is much lower than the pathological state concentration of Tau ∼400 pg/mL. Furthermore, our findings proves that MFN can successfully differentiate normal individuals from Alzheimer’s disease (AD) patients based on clinical samples analysis.