Evaluation of VSK separation in the classification of two mineralogically different iron ore fines

With gradually diminishing Fe grade in tandem with the ever-increasing demand for high-grade iron ores,iron ore industries are now focusing on the beneficiation of low-grade iron ore fines,mainly considered waste.Besides,the scarcity of water at many of the mines’sites and the new water conservation policies of the governments have necessitated research on suitable dry beneficiation routes.In this context,an effort has been made to evaluate the efficacy of a dry classification unit,such as the VSK separator,in upgrading the iron values of two low-grade Indian iron ore fines,named Sample 1 and Sample 2.The mineralogical studies,involving scanning electron microscopy and X-ray diffraction,suggest that Sample 1 is a low-grade blue dust sample(51.2wt%Fe)containing hematite and quartz as the major minerals,while Sample 2(53.3wt%Fe)shows the presence of goethite in addition to hematite and quartz.The experiments,carried out using Box-Benkhen statistical design,indicate that blower speed,followed by feed rate,is the most influencing operating parameter in obtaining a good product in the VSK separator.At optimum levels of the operating factors,a fines product with~55wt%Fe at a yield of~40%can be obtained from Sample 1,while Sample 2 can be upgraded to~56wt%Fe at a yield of~85%.The results suggest that the VSK separator can be employed as an efficient intermediate unit operation in a processing circuit to upgrade the iron contents of iron ore fines.

Enhanced H_(2) permeation and CO_(2) tolerance of self-assembled ceramic-metal-ceramic BZCYYb-Ni-CeO_(2) hybrid membrane for hydrogen separation

Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability.

Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation

Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions （i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%）. The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.

Efficient enrichment of nickel and iron in laterite nickel ore by deep reduction and magnetic separation

The process of deep reduction and magnetic separation was proposed to enrich nickel and iron from laterite nickel ores.Results show that nickel-iron concentrates with nickel grade of 6.96%,nickel recovery of 94.06%,iron grade of 34.74%,and iron recovery of 80.44% could be obtained after magnetic separation under the conditions of reduction temperature of 1275℃,reduction time of 50 min,slag basicity of 1.0,carbon-containing coefficient of 2.5,and magnetic field strength of 72 kA/m.Reduction temperature and time affected the possibility of deep reduction and reaction progress.Slag basicity affected the composition of slag in burden and the spilling and enriching rate of nickel-iron from a matrix to form nickel-iron particles.Nickel-iron particles were generated,aggregated,and grew gradually in the reduction process.Nickel-iron particles can be effectively separated from gangue minerals by magnetic separation.

Effect of desliming on the magnetic separation of low-grade ferruginous manganese ore

In the present investigation, magnetic separation studies using an induced roll magnetic separator were conducted to beneficiate low-grade ferruginous manganese ore. The feed ore was assayed to contain 22.4% Mn and 35.9% SiO2, with a manganese-to-iron mass ratio （Mn：Fe ratio） of 1.6. This ore was characterized in detail using different techniques, including quantitative evaluation of minerals by scan- ning electron microscopy, which revealed that the ore is extremely siliceous in nature and that the associated gangue minerals are more or less evenly distributed in almost all of the size fractions in major proportion. Magnetic separation studies were conducted on both the as-received ore fines and the classified fines to enrich their manganese content and Mn：Fe ratio. The results indicated that the efficiency of separation for deslimed fines was better than that for the treated unclassified bulk sample. On the basis of these results, we proposed a proc- ess flow sheet for the beneficiation of low-grade manganese ore fines using a Floatex density separator as a pre-concentrator followed by two-stage magnetic separation. The overall recovery of manganese in the final product from the proposed flow sheet is 44.7% with an assay value of 45.8% and the Mn：Fe ratio of 3.1.

Microwave-assisted reduction roasting–magnetic separation studies of two mineralogically different low-grade iron ores

The microwave-assisted reduction behaviours of two low-grade iron ores having a similar Fe content of 49wt%but distinctly different mineralogical and liberation characteristics were studied.Their performances in terms of the iron grade and recovery as obtained from statistically designed microwave(MW)roasting followed by low-intensity magnetic separation(LIMS)experiments were compared.At respective optimum conditions,the titano-magnetite ore(O1)could yield an iron concentrate of 62.57%Fe grade and 60.01%Fe recovery,while the goethitic ore(O2)could be upgraded to a concentrate of 64.4%Fe grade and 33.3%Fe recovery.Compared with the goethitic ore,the titanomagnetite ore responded better to MW heating.The characterization studies of the feed and roasted products obtained at different power and time conditions using X-ray diffraction,optical microscopy,vibrating-sample magnetometry,and electron-probe microanalysis explain the sequential reduction in the iron oxide phases.Finally,taking advantage of the MW absorbing character of the titano-magnetite ore,a blend of the same with the goethite-rich ore at a weight ratio of 60:40(O2:O1)was subjected to MW roasting that resulted in a concentrate of 61.57%Fe grade with a Fe recovery of 64.47%.

Triboelectric properties of ilmenite and quartz minerals and investigation of triboelectric separation of ilmenite ore

Triboelectric separation, as an entirely dry technology, is a prospective method to process fine minerals.The aim of this paper is to investigate the performance of triboelectric separation of ilmenite and quartz minerals in a lab unit and to get ready for the separation of ilmenite ore. A tribocharge measurement system was used to test the triboelectric properties of ilmenite and quartz particles with tribochargers respectively made of PVC, PPR, PMMA, Teflon, copper, stainless steel and quartz glass. The results show that the ilmenite particles charged positively while quartz charged negatively when tribocharged with PVC tribocharger. The mixture of 12% ilmenite and 88% quartz was prepared for the triboelectric separation. The recovery of ilmenite increases with the increase of airflow rate, decreases with the increasing feed rate, and grows up firstly and then decreases with the increasing voltage. A maximum ilmenite recovery of 51.71% with ilmenite content 32.72% was obtained at 40 m^3/h airflow rate, 6 g/s feed rate and 20 kV voltage. According to the optimal parameters of the separation of ilmenite and quartz mixture,fine ilmenite ore with 7.55% Ti content was beneficiated using the unit and the Ti content increased to 12.32% in concentrate product.

Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation

Successful recovery of limonite from iron fines was achieved by using flocculation-high intensity magnetic separation （FIMS） and adding hydrolyzed and causticized flocculants according to the characteristic of iron fines. The separation results of the three iron samples are as follows： iron grade 66.77%- 67.98% and the recovery of iron 69.26%-70.70% by the FIMS process with flocculants. The comparative results show that under the same separation conditions the F1MS process can effectively increase the recovery of iron by 10. 97%- 15.73%. The flowsheet results confirm the reliability of the process in a SHP high intensity magnetic separator. The concentrate product can he used as raw materials for direct reduction iron-smelting. The hydrolyzed and causticized flocculants can selectively flocculate fine feebly-magnetic iron mineral particles to increase their apparent separation sizes. The larger the separation size, the stronger the magnetic force. By comparing the separation results of the three samples it is found that among the three samples the higher the limonite content, the better the separation result. This means that the separation result relates closely to the flocculation process and the adding pattern of the flocculant.

Synchronous enrichment of phosphorus and iron from a high-phosphorus oolitic hematite ore to prepare Fe-P alloy by direct reduction-magnetic separation process

In this study,direct reduction-magnetic separation process was applied to enrich phosphorus and iron to prepare Fe-P crude alloy from a high phosphorus oolitic hematite ore(HPOH).The results show that at lower temperatures and with absence of any of additives,Fe cannot be effectively recovered because of the oolitic structure is not destroyed.In contrast,under the conditions of 15%Na_(2)SO_(4)and reducing at 1050℃ for 120 min with a total C/Fe ratio(molar ratio)of 8.5,a final Fe-P alloy containing 92.40%Fe and 1.09%P can be obtained at an overall iron recovery of 95.43%and phosphorus recovery of 68.98%,respectively.This metallized Fe-P powder can be applied as the burden for production of weathering resistant steels.The developed process can provide an alternative for effective and green utilization of high phosphorus iron ore.

Investigation of Peak Separation for X-ray Diffraction Profiles of Spinodal Decomposition by a Kind of Optimized Voigt Function

The intensity and position of sidebands (satellites) on both sides of main diffraction peak in a great number of X-ray diffraction profiles of alloys always change with progress of aging. The sidebands position is determined by a newly optimized Voigt function in present investigation. Furthermore, for Cu-4 wt pet Ti alloy aged at 400℃ for 720 min and 1080 min, after introducing the weight factor of above two satellites intensity, the relative error between the fitting curves and X-ray diffraction profiles is less than 0.185%, which is more precise than the previously calculating result.

Effect of magnetic pulse pretreatment on grindability of a magnetite ore and its implication on magnetic separation

The pulsed power is a potential means for energy saving and presents an alternative to the conventional mechanical communication for minerals.The effect of magnetic pulse treatment on grindability of a magnetite ore was investigated by grindability tests.The results of the investigation show that the pulsed treatment has little effect on the particle size distribution of the magnetite ore.Significant micro-cracks or fractures are not found by SEM analysis in magnetic pulse treated sample.Magnetic separation of magnetic pulse treated and untreated magnetite ore indicates that iron recovery increases from 81.3% in the untreated sample to 87.7% in the magnetic pulse treated sample,and the corresponding iron grade increases from 42.1% to 44.4%.The results demonstrate that the magnetic pulse treatment does not significantly weaken the mineral grain boundaries or facilitate the liberation of minerals,but is beneficial to magnetic separation.

Ferronickel enrichment by fine particle reduction and magnetic separation from nickel laterite ore

Ferronickel enrichment and extraction from nickel laterite ore were studied through reduction and magnetic separation. Reduction experiments were performed using hydrogen and carbon monoxide as reductants at different temperatures （700-1000℃）. Magnetic separa- tion of the reduced products was conducted using a SLon-100 cycle pulsating magnetic separator （1.2 T）. Composition analysis indicates that the nickel laterite ore contains a total iron content of 22.50wt% and a total nickel content of 1.91wt%. Its mineral composition mainly con- sists of serpentine, hortonolite, and goethite. During the reduction process, the grade of nickel and iron in the products increases with in- creasing reduction temperature. Although a higher temperature is more favorable for reduction, the temperature exceeding 1000℃ results in sintering of the products, preventing magnetic separation. After magnetic separation, the maximum total nickel and iron concentrations are 5.43wt% and 56.86wt%, and the corresponding recovery rates are 84.38% and 53.76%, respectively.

Magnetic separation studies for a low grade siliceous iron ore sample

Investigations were carried out, on a low grade siliceous iron ore sample by magnetic separation, to establish its amenability for physical beneficiation. Mineralogical studies revealed that the sample consists of magnetite, hematite and goethite as major opaque oxide minerals where as silicates as well as carbonates form the gangue minerals in the sample. Processes involving combination of classification, dry magnetic separation and wet magnetic separation were carried out to upgrade the low grade siliceous iron ore sample to make it suitable as a marketable product. The sample was first ground and each closed size sieve fractions were subjected to dry magnetic separation and it was observed that limited upgradation is possible. The ground sample was subjected to different finer sizes and separated by wet low intensity magnetic separator. It was possible to obtain a magnetic concentrate of 67% Fe by recovering 90% of iron values at below 200 lm size.

Radiological and X-Ray Diffraction Characterization of Bauxite and Rutile Ore Contaminated Environment in Kanam and Wase Mineral Exploration Sites, Plateau State-Nigeria

Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides 238U, 232Th, and 40K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of 238U, 232Th, and 40K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.

Enrichment of Nb and Ti from carbonatite pyrochlore ore via calcining-slaking followed by gravity separation

In this work,a novel process consisting of calcining-slaking followed by gravity separation for the enrichment of niobium(Nb)and titanium(Ti)from carbonatite pyrochlore ore was proposed,validated and compared with the current mainstream flotation method.During calcining of the pyrochlore ore,within which the carbonates were transformed into lime.Subsequently,when the calcined ore was slaked,lime was transformed into hydroxide with fine particles which were amenable to gravity separation.After calcining at 900℃for 60 min,slaking at 90℃for 10 min with a liquid–solid ratio of 3:1(mL/g),approximately 40%of tailings can be removed by gravity separation,the recoveries of Nb and Ti were 94.7%and 91.0%,and the enrichment ratios of Nb and Ti were 1.61 and 1.43,respectively.The new approach exhibits high separation efficiency of carbonate gangue minerals and valuable minerals,satisfactory recoveries of niobium as well as titanium can be achieved.

Removal of Silica and Alumina as Impurities from Low-Grade Iron Ore Using Wet High-Intensity Magnetic Separation and Reverse Flotation

This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.

New Technology “Flotation to Form Agglomerates and Magnetic Separation” Allows Great Breakthrough for World Low-Grade Light Rare Earth Ores

Rare earth resources are relatively scarce worldwide, but their global consumption is increasing year-by-year. At present, China has about 36% of the global rare earth reserves, but provides 90% of the world＇s supply, which has generally met world demand and promoted the development of the world economy. In order to continuously and stably supply rare earths to international markets, the Chinese Government has financially supported the Institute of Multipurpose Utilization of Mineral Resources within the China Geological Survey to study the utilization of low-grade rare earth ores. Following many years of experimental research, the project has developed a new technology entitled ＂Flotation to Form Agglomerates and then Magnetic Separation＂, which will bring a technological revolution to the world＇s light rare earth ore dressing.

Effectiveness of Gravity Separation of Low Grade Nigerian Gold Ore Using Shaking Table

The response of Imogbara (Nigeria) gold ore to shaking tabling gravity separation methods was investigated in this research work. Gold concentration in run-off mines is usually as low as 0.005 ppm and must be upgraded in order to reduce the recovery process extraction costs. Gravity separation method (the focus of this work) is one of the readily affordable beneficiation methods. Shaking table is a developed separation equipment of gravity method that has been adopted to increase concentrate based on difference of specific gravity. The output result of the concentration process using shaking table is basically influenced by a number of variables, such as rotational shaking speed, particle size and deck slope. In this research, the range of rotational speed shaking was between 100 rpm and 200 rpm, the particle size was between (−300 μm > X −75 μm) and deck slope was between 10°and 30°. EDXRF was used to measure gold concentration in the concentrate as well as the tailings. The result shows that the optimum condition is obtained at a shaking speed of 100 rpm, with a slope of 10°and particle size less than 75 μm.

Metalizing reduction and magnetic separation of vanadium titano-magnetite based on hot briquetting

To achieve high efficiency utilization of Panzhihua vanadium titano-magnetite, a new process of metalizing reduction and magnetic separation based on hot briquetting is proposed, and factors that affect the cold strength of the hot-briquetting products and the efficiency of reduction and magnetic separation are successively investigated through laboratory experiments. The relevant mechanisms are elucidated on the basis of microstructural observations. Experimental results show that the optimal process parameters for hot briquetting include a hot briquetting temperature of 475°C, a carbon ratio of 1.2, ore and coal particle sizes of less than 74 μm. Additionally, with respect to metalizing reduction and magnetic separation, the rational parameters include a magnetic field intensity of 50 mT, a reduction temperature of 1350°C, a reduction time of 60 min, and a carbon ratio of 1.2. Under these above conditions, the crushing strength of the hot-briquetting agglomerates is 1480 N, and the recovery ratios of iron, vanadium, and titanium are as high as 91.19%, 61.82%, and 85.31%, respectively. The new process of metalizing reduction and magnetic separation based on hot briquetting demonstrates the evident technological advantages of high efficiency separation of iron from other valuable elements in the vanadium titano-magnetite.

Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample (I center dot 4.6 mm x 5.6 mm) was scanned using high-resolution X-ray computed tomography (HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 mu m. Combined with three-dimensional (3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.