Wet Magnetic Separation Research Articles

Recovery of Iron values through conventional beneficiation techniques from Banded Hematite Jasper of Eastern India with special reference to mineralogical and chemical characterization

Background/Objectives: Due to soaring demand and rapid depletion of high-grade iron ores, lean grade iron ores of India like BHJ and BHQ needs to be utilized through suitable beneficiation techniques. Methods: Banded Hematite Jasper (BHJ) sample of Bonai-Keonjhar belt (BK belt), Odisha, India assayed 35.3 % Fe, 47.1% SiO2 and 0.96% Al2O3 was investigated in respect of mineralogy, liberation characteristics and chemistry to finding out its optimum beneficiation potential. In the present investigation, efforts have been made to characterize the BHJ sample with reference to its beneficiation response. The sample was subjected to various beneficiation operations like Jigging followed by hydrocyclone, two-stage tabling and magnetic Separation. Findings: Mineralogical studies indicate that quartz and hematite are the major mineral phases, whereas goethite, martitized magnetite and clay (kaolinite) are present in very minor amounts. The liberation characteristic indicates that the average band thickness of Iron bearing mineral is of 1680 microns and 80% of the iron bearing minerals are liberated at -105 microns size. The two stage tabling of jig concentrate with desliming gives better outcome as compared with direct tabling of jig concentrate. An iron ore concentrate assayed 64.5% Fe, 5.6% SiO2 and 0.80% Al2O3 with wt% recovery of 23.2% can be obtained from two stage tabling. Another concentrate from magnetic separation of table middling and hydrocyclone assayed 63.2% Fe, 7.2% SiO2 and 0.7% Al2O3 with wt% recovery of 12.4% can be obtained. Novelty/ Application: Here a conventional beneficiation flow sheet is developed with a finding that, in order to beneficiate ore like banded hematite jasper (BHJ), an integral characterization approach is very much essential. Both of the concentrates obtained through the flow sheet assayed 64% Fe, 6.2% SiO2 and 0.7% Al2O3 with a wt% recovery of 35.6% can be utilized as a feed stock for pellet making in iron ore industries. Keywords: Banded Hematite Jasper (BHJ); mineral beneficiation; wet high intensity magnetic separator (WHIMS); jigging; Bonai-Keonjhar belt

As sorption onto Fe-based nanoparticles and recovery from soils by means of wet high intensity magnetic separation

In this work, we studied the soil washing of an As-polluted soil utilizing Wet High Intensity Magnetic Separation (WHIMS) after pre-treatment with nanoparticles. First, Fe-Ni nanoparticles of high saturation magnetization and appropriate size were synthesized. Soil samples were then pre-treated with a dose of nanoparticles before undergoing magnetic separation at different field intensities. Two nanoparticles doses were used and, in addition, control trials with un-pre-treated soil were also performed. Nickel concentration, and magnetic properties served to evaluate the underlying physical behavior of the nanoparticles subjected to magnetic separation. Additionally, leaching tests and As speciation was performed to evaluate As immobilization due to sorption onto the nanoparticles. For the interpretation of the chemical separation results we propose a novel efficiency index, considering both As concentration and weight recoveries. Results show that separation efficiency after nanoparticles pre-treatment yielded better results for lower separation voltages than no pre-treatment, indicating that nanoparticles reported to the magnetic fraction with the As adsorbed onto them. In contrast, at higher separation voltages, more paramagnetic materials reported to the magnetic fraction, thus hindering As separation. Besides, As immobilization was also observed in the nanoparticles pre-treated samples. Accordingly, we obtained a combined soil treatment approach, involving both, the reduction of the volume of polluted soil (physical soil washing) and its stabilization.

Up-Concentration of Chromium in Stainless Steel Slag and Ferrochromium Slags by Magnetic and Gravity Separation

Slags coming from stainless steel (SS) and ferrochromium (FeCr) production generally contain between 1 and 10% Cr, mostly present in entrapped metallic particles (Fe–Cr alloys) and in spinel structures. To recover Cr from these slags, magnetic and gravity separation techniques were tested for up-concentrating Cr in a fraction for further processing. In case of SS slag and low carbon (LC) FeCr slag a wet high intensity magnetic separation can up-concentrate Cr in the SS slag (fraction <150 µm) from 2.3 wt.% to almost 9 wt.% with a yield of 7 wt.%, and in the LC FeCr slag from 3.1 wt.% to 11 wt.% with a yield of 3 wt.%. Different behavior of Cr-containing spinel’s in the two slag types observed during magnetic separation can be explained by the presence or absence of Fe in the lattice of the Cr-containing spinel’s, which affects their magnetic susceptibility. The Cr content of the concentrates is low compared to chromium ores, indicating that additional processing steps are necessary for a recovery process. In the case of high carbon (HC) FeCr slag, a Cr up-concentration by a factor of more than three (from 9 wt.% to 28 wt.%) can be achieved on the as received slag, after a single dry low intensity magnetic separation step, due to the well-liberated Cr-rich compounds present in this slag. After gravity separation of the HC FeCr slag, a fraction with a Cr content close to high grade Cr ores (≥50% Cr2O3) can be obtained. This fraction represents 12 wt.% of the HC FeCr slag, and can probably be used directly in traditional smelting processes.

Generation of titania-rich slag and iron from ilmenite concentrate by carbothermic reduction and magnetic separation in the presence of Na2CO3

ABSTRACT The carbothermic reduction of an ilmenite concentrate, followed by wet magnetic separation, was performed with varying additions of Na2CO3 to generate metallic iron and a titanium-rich slag. The size of the metallic iron particles correlated positively with increasing graphite addition up to a C/O (O bound to Fe) molar ratio of 1.4; further increases beyond this level decreased the particle size. The size of these metallic iron particles also increased with greater addition of Na2CO3. The addition of Na2CO3 to the ilmenite concentrate enhances the carbothermic reduction by promoting the gasification of C and fluxing the slag phase, lowering its melting point and increasing fluidity; a 5.97 wt% addition of Na2CO3 decreased the reduction onset temperature from 1020 to 900°C. This fluxing of the slag with Na2CO3 also allows for much lower concentrations of FeO than the 10–12% concentration typically required to ensure adequate fluidity in conventional EAF smelting operations. With the addition of Na2CO3, the recovery of Fe to the magnetic fraction, following magnetic separation, was over 97% and the non-magnetic fraction contained more than 74% TiO2. Within the range of conditions considered in this study, the highest recovery of TiO2 to the non-magnetic fraction (89%) was achieved for material reduced at 1450°C.

Characterization of the Angico dos Dias alkaline-carbonatite complex for phosphate rock processing

The alkaline-carbonatite complex of Angico dos Dias, located in the Northeast of Brazil, is currently exploited to produce phosphate rock concentrate. Coarse particles (above 600 µm) are processed through a dry route accounting for 53% of the run of mine. Chemical and mineralogical compositions, density, particle size distribution, mineralogical associations, and mineral liberation were determined. A wet processing route for the fine particles was proposed in this paper, comprehending the following stages: scrubbing, low-intensity magnetic separation, desliming, milling, anionic direct flotation, and wet high-intensity magnetic separation. X-ray diffraction analysis showed fluorapatite as the main phosphate bearing mineral, silicates and iron oxyhydroxides are the predominantly gangue minerals. Mineral liberation analysis showed that 40.8% of the apatite particles had completely exposed surface and 73.05% had at least 90%. Regarding mineral liberation, 87.6% were entirely liberated and 11.6% were binary association. Energy dispersive spectrum microanalysis results showed the presence of three rare earth elements bearing minerals in the ore. The average P2O5 content of the ROM ore was 15.39%, and its recovery above 212 µm was 76.95%. Below this size, the P2O5 content decrease progressively, whereas the Fe2O3, Al2O3, and SiO2 contaminants increase. The absence of calcite and dolomite could favor the process selectivity in an anionic direct flotation using fatty acids as collectors. Therefore, the proposal for a wet processing design for concentration of apatite covers.

Preconcentration of Iron, Rare Earth, and Fluorite from Bayan Obo Ore Using Superconducting Magnetic Separation

Bayan Obo ore contains mainly bastnaesite, monazite and associated iron, fluorite, calcite, dolomite, barite, and trace amount of columbite. Due to its complex mineral compositions and similar mineral properties, it is difficult to separate and obtain rare earth and fluorite concentrates with high purity by conventional magnetic separation and flotation. In this paper, a stepwise magnetic separation process comprised of wet permanent magnetic separation (PMS), wet electromagnetic separation (EMS), and superconducting magnetic separation (SCMS) was proposed to pre-concentrate iron, rare earth, and fluorite minerals from Bayan Obo ore. The results showed that iron, rare earth, and fluorite preconcentrates with high purity and low impurity content could be achieved, which might be helpful to shorten the technological process and improve the separation efficiency for the subsequent flotation of iron, rare earth, and fluorite minerals.

Research on Some Physicochemical Parameters of Artificially Created Soil Mixtures

Compositions of artificial soil mixtures, including sand, clay, defecation mud, waste from wet magnetic separation and plant residues in different proportions have been developed. The components were preliminarily comminuted by an auger-drill in order to obtain a homogeneous composition with subsequent granulation, stored in natural conditions in the autumn-winter period, followed by filling in experimental vessels. No any phytotoxic effect for the initial components and for all analyzed samples of the obtained artificial soil mixtures was detected. The chemical composition and some physicochemical properties of artificial soil mixtures, such as density, deposit of moisture and humus content, were determined. It was shown that the samples of the obtained soil mixtures are close to the control (dark gray forest soil of the Belgorod region) and can be recommended for further use in creating cultural landscapes as a substitute for natural soil. The developed type of artificial soil mixtures is suitable for the cultivation of bulbous crops; moreover, a large increase in yield in comparison with the control for some compositions was found. Artificially created soil mixtures reduce the harmful effect on the environment by eliminating the storage of industrial waste such as iron ore and food, plant residues used in the composition of the artificial soil mixture. Artificial soil mixture can be used for remediation of technologically disrupted areas, which will allow restoring disturbed lands and reducing man-caused impact on solid waste landfills. The addition of industrial waste allows them to be re-involved in the technological cycle, which contributes to the development of low-waste and waste-free technologies. The results obtained indicate the possibility of using the studied soil mixtures for cultivation of the decorative bulbous plants. To recommend the developed compositions for the use in agriculture, it is necessary to assess the possibility of impurity translocation from soil samples into cultivated crops.

Iron recovery from zinc mine tailings by magnetic separation followed by carbothermal reduction of self‐reducing briquettes

AbstractThe volume of tailings produced by the extractive industry has been increasing due to the processing of the low‐grade ore. This issue can cause environmental accidents and require significant investment to control the disposal of tailings. Therefore, this study aims to recover iron from zinc mine tailings by wet magnetic separation followed by the carbothermal reduction of self‐reducing briquettes. Two magnetic separation routes were investigated to concentrate iron. Zinc mine tailings were processed by route I, in a rougher stage followed by a scavenger stage; and route II, in a rougher stage followed by a cleaner stage. The carbothermal reductions were performed using self‐reducing briquettes composed of Fe concentrate from the route with high Fe content and charcoal. The products were analyzed by scanning electron microscopy with energy dispersive spectroscopy (SEM‐EDS), x‐ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP‐OES), and volumetric chemical analysis. Magnetic separation route II provided the highest‐grade Fe concentrate, 52% Fe, while route I provided 33% Fe. In the carbothermal reductions, a metallization degree of 98% in the Fe concentrate briquette, 97% in the briquette with a 10% replacement of its raw material by Fe concentrate, and 99% in the hematite briquette was reached. The replacement of raw material by Fe concentrate showed no significant change in Fe recovery. Considering the whole process, magnetic separation and carbothermal reduction, the recovery of Fe from the zinc mine tailings was 67%. Therefore, the process route suggested in this study will not only reduce tailings disposal and consequently the risk of environmental accidents, but it will also provide profitable raw material for the steel industry.

The Mechanical Alloying of Magnetite Concentrate with Biochar

Aim:In this work, the effect of milling time on the mechanical alloying of the mixture containing the magnetite concentrate and biomass waste was investigated.Materials and Methods:The ore’s grade consisting of hematite and magnetite minerals was increased from 49.87% Fe to 67.29% Fe using the low intensity wet magnetic separator. Biomass waste which was supplied from ÇAYKUR black tea facilities, used as a carbon source was subjected to carbonization processes at 800°C for 1440 min. After the carbonization process, the carbon and sulphur contents of the biomass were measured as 94.68% and 0.03%, respectively. For the mechanical alloying process, a mixture consisting of magnetite concentrate with a grain size of -45 μm and biomass which was added two times the amount of carbon required for the reduction of magnetite to metallic iron was used.Result:After the mechanical alloying process which was carried out at different times, it was observed in the particle size analysis that the particle size of 90% of the mixture was reduced to about 4 μm. In SEM (Scanning Electron Microscopy) images, cube-like particles along with the spherical particles were observed depending on the mechanical alloying times. After 45 minutes of alloying, it was observed that the carbonized product milled together with magnetite concentrate was partially integrated into the crystal structure.Conclusion:The carbonized tea plant waste milled together with magnetite concentrate was partially integrated into the crystal structure. And the mechanical alloying provide to increase in the specific surface area in parallel with the grain size decrease in the study. Thus, in the later stage of the study, the milled powder acquired more ability to react.

Processing of Low-Grade Chromite Ore for Ferroalloy Production: A Case Study from Ghutrigaon, Odisha, India

The low-grade siliceous chromite ore from Ghutrigaon, Odisha, India, containing ~ 16% Cr2O3, with Cr/Fe ratio of 1.97 and ~ 55% of SiO2, does not find any use in metallurgical industry and hence considered as waste. Mineralogical investigation indicates the presence of chromite and quartz as major minerals with minor fuchsite and kaolinite. The beneficiation studies reveal that the product can be enriched to a Cr/Fe ratio of 3.35 and 3.02 by gravity concentration (wet shaking table) and wet high intensity magnetic separation, respectively. Tiny Cr-grains within quartz and fine silica dusts within chromite inhibit liberation of chromite resulting in poor response to physical beneficiation. As an alternative, processing of ore through pyro-metallurgical route was evaluated. Chromite fines mixed with carbon and lime in the form of pellets/granules was charged to a plasma reactor. In about ten minutes, the metal globules/prills were separated from the slag in 1:6 ratio. The metal, examined through XRD and optical microscope, was found to be ferrochrome alloy. In situ EDAX analysis indicated the metal to have 61.51% Cr, 26.52% Fe and 13.1% C with minor silica (2.42%), and the slag was composed of Ca2Al2SiO7 which revealed that both metal and slag so obtained could suitably be used in different industries.

Study of Low-Grade Nickel Laterite Processing Using Palm Shell Charcoal as Reductant

This study was conducted to investigate the effect of palm shell charcoal reductant in the selective reduction of nickel ore with the addition of additive at various temperatures and times. In this present work, 10 wt. % of sodium sulfate as additive and 5, 10, 15 wt. % of palm shell charcoal as reductants were used. The reduction of nickel ore was performed at 950oC, 1050oC, and 1150oC for 60, 90, and 120 minutes. A wet magnetic separation method was then carried out to separate the concentrates and tailings. Characterization of reduced ore was performed by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), while the composition of ferronickel in concentrate was identified by X-Ray Fluorescence (XRF). The result showed that the higher temperature reduction, the higher of nickel grade, and its recovery at the concentrate. Nevertheless, the longer reduction time and the more reductant in nickel ore lowering the nickel grade and its recovery in the concentrate. The optimum condition in this selective reduction process was obtained with the addition of 5 wt. % of reductant and 10 wt. % of sodium sulfate in nickel ore, which was reduced at 1150oC for 60 minutes. It resulted in 4.60% and 73.23% for nickel grade and its recovery, respectively.

Studies on Beneficiation of Manganese Ore through High Intensity Magnetic Separator

Upgradation techniques like wet sieving and magnetic separation were used to evaluate the beneficiation potential of manganese ore. During wet sieving, manganese content in raw ore was upgraded from 27% to a maximum value of 38% in the concentrate with a recovery of 30%. Size classification was found to have no measurable effect on manganese grade in magnetic separation. In the unsieved ground ore, manganese content of 45% was achieved with a recovery of 23% and Mn/Fe ratio of 19% at a magnetic intensity of 8500 Gauss. At the same operating conditions, SiO2 was reduced from 56% in the raw ore to 30% in the magnetic fraction. So, wet sieving technique leads to a comparatively lower manganese grade but better recovery. Conversely, a magnetic separation technique produced higher manganese grade but relatively lower recovery. Blending of the upgraded manganese ore with high grade iron ore can be done to achieve the required Mn/Fe ratio.

Co-Treatment of Spent Pot-Lining and Red Mud for Carbon Reutilization and Recovery of Iron, Aluminum and Sodium by Reductive Roasting Process

Spent pot-lining (SPL) and red mud (RM) are the two major solid wastes of the aluminum industry. In this study, an innovative method has been proposed for co-treatment of SPL and RM to reuse carbon and recover metal (iron, aluminum and sodium) by a reductive roasting-leaching-magnetic separation process (RRLMS process). Moreover, the transformation behaviors of fluoride, cyanide and sulfur present in these residues were studied. The effects of parameters such as temperature, CaO/SiO2 molar ratio, addition amount of SPL, Na2O/Al2O3 molar ratio and roasting time on the result of the process were investigated. Under optimum conditions, the recovery extents of Al2O3 and Na2O were 83.12 and 91.80 pct, respectively. The corresponding leaching extent and loss of F upon roasting process were 16.03 and 35.27 pct, respectively, and only 29.02 pct of ST in the roasted product was leached. Furthermore, reduction extent of 78.65 pct and a metallization extent of 62.83 pct for iron minerals were achieved. The SPL-RM mixture after treatment was rendered non-hazardous. Finally, wet magnetic separation at 1.2 A current (magnetic field strength of approximately 130 mT) provided 30.83 wt pct concentrate yield with 59.09 wt pct total iron concentration and iron recovery extent of 65.25 pct from the leached residue.

Assessing the performance of a novel pneumatic magnetic separator for the beneficiation of magnetite ore

A novel low-intensity pneumatic planar magnetic separator designed to recover and concentrate fine-grained magnetite minerals is investigated and the performance compared with those of conventional wet magnetic separators, i.e., Davis tube tester and drum magnetic separator. The results of the studies show that the magnetite recoveries and grades achieved by the novel planar magnetic separator compare favourably with that of the Davis tube tester. Moreover, the outcomes of the studies show that the magnetite concentrates recovered by the planar magnetic separator showed higher magnetite grades with fewer impurities than that of the wet drum magnetic separator. The findings from the study show that the planar magnetic separator could be a potential laboratory-scale substitute for the Davis tube tester, as well as replace wet magnetite beneficiation technologies in drought-ridden and remote regions where the paucity of water could be a potential economic challenge to wet processes.

Roasting of a Low-Grade Goethite Ore Using Horse Residue and Its Beneficiation by Magnetic Separation

In the present study, the use of horse residue as an alternative reducing agent in the roasting of a low-grade goethite ore containing 17.60% Fe was investigated. Additional roasting experiments were carried out with corn starch and without reducing agent for comparison. Each roasted product was characterized using X-ray diffraction (XRD) and magnetic hysteresis (MH) loops analyses. The optimum roasting conditions (roasting temperature [400, 500, and 600 °C], reducing agent/ore ratio [0.04, 0.08, and 0.12], and roasting time [10, 20, and 30 min]) were investigated based on the Taguchi approach. The magnetic susceptibilities of the roasted sample with the addition of reducing agents were higher compared to that of the roasted sample in the absence of reducing agent. Experimental findings indicate that the horse residue can be used as the reducing agent. Finally, an iron ore concentrate assaying a Fe grade of 62.12% with a recovery of 56.93% was prepared using wet magnetic separation at a magnetic intensity of 0.5 T from the ore roasted under the following roasting conditions: roasting temperature of 500 °C, reducing agent/sample ratio of 0.08, and roasting time of 30 min.

ИЗУЧЕНИЕ ФИЗИКО-МЕХАНИЧЕСКИХ СВОЙСТВ АСФАЛЬТОБЕТОННЫХ ОБРАЗЦОВ НА АКТИВИРОВАННЫХ МИНЕРАЛЬНЫХ ПОРОШКАХ РАЗЛИЧНЫХ СОСТАВОВ

the article presents the results of testing asphalt samples based on activated mineral powder from silica-containing raw materials. Activated filler was obtained by joint grinding of waste wet magnetic separation (WMS) of ferruginous quartzites of the Kursk Magnetic Anomaly in a spherical planetary mill in the presence of surfactants (stearic acid, adhesive additive Amdor-10) and bitumen. First of all, it should be noted that the use of activated mineral powder in the composition of asphalt concrete mixture led to an increase in the packing density of the composite. This was reflected not only in the technological process, but also contributed to the decrease in the porosity of the mineral core. It was found that the use of surfactants in the process of grinding mineral powder made it possible to increase the strength of asphalt concrete samples. However, the change in the crack resistance and shear resistance of asphalt concrete specimens, determined from the ratio of the corresponding compressive strengths, did not occur (table). This is due to the fact that there has been a proportional change in all the strength characteristics at different temperatures. Analysis of the physical-mechanical characteristics of the properties of asphalt concrete led to the conclusion that it was possible to use activated mineral powder from waste WMS as a component of asphalt concrete mixtures.

Cleaning up Emergency Oil Spills from the Water Surface with Magnetic Adsorbents

There was suggested a method of obtaining a complex adsorbent with magnetic properties for the oil spill clean-up from the water surface by means of controlled magnetic field. As magnetic filler a finely-dispersed iron-ore concentrate in the form of magnetite, obtained by wet magnetic separation of crushed iron ore, was suggested. As an adsorbing component the disintegrating electric-furnace steelmaking slag, obtained by dry air-cooling method, was selected. The mass ratio of components slag:magnetite is 1(1,5÷2,0). For cleaning up emergency oil spills with the suggested magnetic adsorbent a facility, which is installed on a twin-hulled oil recovery vessel, was designed. The vessel contains a rectangular case between the vessel hulls with inlet and outlet for the treated water, the bottom of which is a permanently moving belt. Above the belt, at the end point of it there is an oil-gathering drum with magnetic system. The adsorbent is poured to oil-products layer from a hopper, provided with drum feeder. Due to the increased bulk weight the adsorbent sinks rapidly into the oil layer on the water surface. If the large non-floating flocculi are formed, they sink and sedimentate on the moving belt and are moved to the oil-gathering drum. The saturated adsorbent is removed from the drum surface with a scraper, connected with a gutter, with contains a rotating auger.

Comparative study on concentration properties of iron deposits (Mongolia)

Research aims to compare magnetic flotation results of iron deposits of Mongolia in order to obtain iron concentrate with low sulfur content that meets the standard of raw materials for metallurgical production. Research methodology. Representative samples were taken from Tumurtei deposit in Khuder soum (Selenge province), Tumur Tolgoi deposit (Darkhan-Uul province) and Chandmani Uul deposit (Dornogobi province). Iron grade in the primary ore from Tumurtei deposit was 42.03%, in Tumurtolgoi ore – 46.57% and in Chandmani-Uul ore–43.59%. The ore was crushed into 1 mm size through java crusher and gyratory crusher for the first stage. Dry magnetic concentration was conducted on the ore samples using Boxmag Rapid LR-1.4 Induced Magnetic Separator (the UK). The test work was conducted under the condition when the distance between gyrator of separator and rotation speed are constant and by this time magnetic strength was changed. At the next stage the concentrate of dry magnetic concentration was processed by wet magnetic separation. In order to reduce the sulfur content in the ore from Tumur tolgoi and Tumurtei deposits, flotation experiments were also conducted using UK Denver flotation machine. Ore and concentrator grade were determined using traditional titer method and X-ray fluorescence spectrometer (XRF), the mineral contents was analyzed by X-ray powder diffraction (XRD), elements in product of wet magnetic separator and final concentrate were analyzed using SEM-EDX, the thermal-gravy meter analysis was conducted using instrument TG/DTA7300. Results. Wet magnetic concentration of dry magnetic separation concentrates of all the studied ore allow obtaining concentrates with the high content of iron – from 64% to 66%. Flotation of the concentrate of wet magnetic concentration made it possible to reach iron content in Tumurtei and Tumurtolgoi deposits of 69.02% and 62.86% correspondingly and reduce Sulphur content to 0.2%, 0.48% correspondingly. This study covers the field of flotation technology to extract products with lower sulfur content which meet standard of modern metallurgical industry.

Magnetic entrainment mechanism of multi-type intergrowth particles for Low-Intensity magnetic separation based on a multiphysics model

Wet low-intensity magnetic separation (LIMS) is used in the magnetic separation of ferromagnetic minerals. The performance of the separation is controlled primarily by the internal flow in the separator, governed by the process and machine settings. However, a very important factor has been usually ignored in the LIMS process, namely the behavior of the intergrowth particles. The detailed influence of the various condition parameters on the behavior of the particles with different characteristics in LIMS is still not clear. In this study, a two-way coupled multiphysics model was used to simulate the dynamic capture process of the multi-type intergrowth particles and its impact on the performance of LIMS separation. All predictions indicate that the operating parameters and particle properties affect the capture behavior of intergrowth particles, which significantly affects the separation performance of the LIMS. Intergrowth particles play an important role in the process of LIMS. Additionally, the capture time for the intergrowth particles of different particle sizes and liberation degrees to reach the drums’ surface from the initial location are different. Because the capture time of the coarse intergrowth particles is much shorter than that of the ultrafine pure magnetic particles, the coarse particles will preferentially accumulate on the drum to cause a magnetic entrainment phenomenon. The phenomenon of magnetic entrainment facilitates the recovery of intergrowth particles. In LIMS, however, for a high grade and recovery magnetic product, intergrowth particles and high liberation is necessary and excessive grinding of the particles should be avoided.

Beneficiation of goethite iron ore through magnetizing roasting followed by magnetic separation

The present study is carried out to recover iron value from low grade goethite iron ore. The method is based on coal based magnetization roasting followed by magnetic separation. The effect of temperature, residence time and magnetic field intensity on grade and recovery of iron ore have been studied. The magnetizing roasting was carried out at 700°C, 800°C and 900°C for different residual time viz., 10, 20, 30, 40, 50 and 60 minutes. The production obtained from magnetizing roasting was then separated in wet high intensity magnetic separator (WHIMS) at different magnetic field of 2000 gauss, 4000 gauss and 6000 gauss. The result obtained at 900°C roasting temperature for 50 minute followed by magnetic separation at 2000 gauss shows optimum Fe grade of 59.20% and recovery is 68.23%, this grade and recovery of iron ore increases with increase of temperature and time. However, the grade and recovery of iron ore decreases during prolonged roasting at 900°C. The recovery increases with increasing in magnetic field but the grade is decreasing. In the present study, the as received goethite iron ore and concentrate ore have been examined using optical microscopy to know the phases present and change of phase during processing.