Low-intensity Magnetic Separation Research Articles

Recovery of iron from Baotou rare earth tailings by magnetizing roast

The difference of physicochemical properties among minerals in Baotou rare earth tailings is not significant, which leads to a great difficulty in separation of minerals. In this article, the process of magnetizing roast and low-intensity magnetic separation was used to recover iron. Effect of calcination temperature, holding time and carbon/oxygen ratio on roasting efficiency was investigated. The parameters evaluating magnetizing roast efficiency and theoretical value were determined. X-ray diffraction (XRD) analysis was used to investigate the conversion of Fe phase after roasting. The results show that the best magnetizing roast conditions are calcination temperature of 650 °C, holding time of 2.5 h, and carbon/oxygen molar ratio of 3.85. The best magnetization rate is 2.36, which is close to the theoretical value of 2.33. Based on experiments of low-intensity magnetic separation under different intensities, the best current intensity is 2.0 A to obtain the best separation results. Under the best condition, the concentrate grade of iron is 45.45 % and the recovery of iron is 68.36 %. Most of rare earth, fluorine, and phosphorus are enriched in the magnetic separation tailings. The XRD analysis shows that Fe exists in Fe2O3 before roasting and exists in Fe3O4 after roasting.

Evaluation of the applicability of ultrasonic velocity profiling in conditions related to wet low intensity magnetic separation

The internal material transport and selection processes of the wet low-intensity magnetic separators (LIMS) are poorly understood; this calls for improved measurement techniques. In this work an ultrasonic velocity profiling (UVP) technique for measuring how material flow velocity varies with penetration depth is presented. A measurement depth of just a couple of centimetres would greatly improve the understanding of the separation process in a LIMS.When applied to flows of mineral suspensions with high volumetric solids concentration, similar to those in the separators, UVP is unique in combining:•Non-intrusive measurements.•Operates using just one sensor element (transducer).•Relatively good spatial resolution.•Penetrates opaque suspensions.•Fast sampling rate.Here, flows are studied in a rectangular duct (50×75mm). Using magnetite suspensions, measurement through the whole depth of 50mm is made with good accuracy. Velocity profiles are presented for solids concentrations of 5% and 9% solids by volume (20% and 36% by weight). Even at 9vol% solids it is possible to reach a penetration depth of more than 25mm.

Study on Comprehensive Recycling of an Ilmenite Ore Beneficiation Test

Ilmenite phase is complex in Shaanxi.There are mainly magnetite, limonite and ilmenite, and associated with extremely small amount of rutile. According to the occurrence iron and titanium in the ilmenite ore。Paper discussed comprehensive recycling of the ilmenite using wet low-intensity magnetic separation by stage grinding process . The results show that it obtains better mineral processing indexes。The productivity of ilmenite concentrate was 28.83%, the grade of iron in concentrate was 62.05%, the content of titanium was 13.11%, iron recovery was 61.73%, titanium recovery was 43.40%.

Flotation of pyrrhotite to produce magnetite concentrates with a sulphur level below 0.05% w/w

Northland Resources is developing several magnetite mineral resources in northern Europe. The Tapuli, Sahavaara and Pellivuoma mineral resources are in Sweden and the Hannukainen resource is in Finland. Three of these resources (Sahavaara, Pellivuoma and Hannukainen) require flotation to remove more than 98% by mass of the sulphur in the feedstock to produce a saleable magnetite concentrate with a sulphur level below 0.05% w/w. The detrimental sulphur containing mineral is monoclinic pyrrhotite and its removal requires flotation. Previous published results related to pyrrhotite flotation from magnetite concentrate, e.g. on a magnetite deposit in Peru, only required the process to produce a final magnetite concentrate with a sulphur level below 0.4% w/w. There is currently no known published information on a process that floats pyrrhotite to achieve a magnetite concentrate with less than 0.05% w/w of sulphur.Extensive bench-scale tests were conducted on samples from Sahavaara, Pellivuoma and Hannukainen. Low-intensity magnetic separation (LIMS) tests showed that LIMS upgraded the magnetite and the sulphur in the pyrrhotite at the same ratio.The final flotation reagent regimes and conditions for each deposit were different being related to differences in mineralogy and grind size. The pH ranged from natural to pH of 4. Large dosage rates of xanthate collectors and long flotation times were needed. Flotation feed percent solids of between 45% and 50% w/w was required. Future work will modify these reagent regimes and flotation conditions in the full-scale plants to further optimise the flotation processes.

Beneficiation of Cassiterite and Iron Minerals From a Tin Tailing with Magnetizing Roasting-Magnetic Separation Process

The beneficiation of cassiterite and iron minerals from tin tailings with magnetizing roasting and low-intensity magnetic separation (MR-LMS) process was studied in this work. It showed that the process was effective in recovering the tin and iron values from the refractory ore, produced a high-quality iron concentrate assaying 64.68% Fe with the recovery of 87.47% and a tin-rich middling assaying 4.10% Sn with the tin recovery of 63.55%, from the tin tailing assaying 0.20% Sn and 14.56% Fe. It has been found that the key point of the process was the step of magnetizing roasting, which converted hematite and limonite into magnetite. The separation efficiency of the process closely correlated with roasting temperature, roasting time, lignite addition, and the liberation of cassiterite with the iron minerals.

Mineral Processing Technology Study on a Lean Hematite Ore with Finely-Disseminated Minerals

The mineral processing experimental research was carried out on the hematite bearing characteristics of low grade, fine grain,complex composition. The results showed that using the technological flowsheet of “stage grinding- low intensity magnetic separation”, the iron concentrate with recovery of 36.56% and grade of 65.85% Fe can be obtained. And the iron concentrate with recovery of 17.23% and grade of 63.53% Fe can be obtained by “stage grinding-HIMS process-reverse flotation” process. The final iron concentrate with TFe grade of 65.10%,yield of 19.19% and total iron recovery of 53.79% from the raw ores with TFe grade of 23.41％ was obtained, with the first stage grinding size being 55% -0.074mm and the second stage,93% -0.074mm.

Beneficiation Test Research on High Grade Hematite-Limonite Ore

The run of mine ore grade of Gan Shang Yan is 47.83%, iron ore grade is higher, but harmful element sulfur and impurity silica content is relatively high. This experiment using a simple process low intensity magnetic separation-high gradient magnetic separation, for the ultimate index for comprehensive grade of iron concentrate is 58.41%, at a total recovery of 80.85%, and obtain good experiment index, the harmful elements and impurity content can meet the standard.

Research on Classified Magnetic Separation of Oolitic Hematite from Guizhou Province

Oolitic hematite is considered to be one of the most refractory ores in the world due to its ultra fine disseminated grain size and complex mineral composition. Various magnetic separation methods were conducted on the oolitic hematite ore samples from Guizhou Province. Because the TFe grades of each size fraction of the grinding products were different from each other, the beneficiation process of “classification – low intensity magnetic separation – high intensity magnetic separation” was finally adopted to guarantee the quality of iron concentrates. After the determined magnetic separation, the relatively good technical indexes are obtained. The TFe grade of iron concentrates is increased from 38.7% to 46.1%, and the iron recovery is 81.7%.

A Novel Process for Titanium Sand by Magnetic Separation and Gravity Concentration

With the continuous depletion of high-grade titanium ores and the increasing demand for titanium dioxide, the low-grade titanium sand has become an important source for the production of ilmenite concentrate; however, the large-scale utilization of the sand is disappointedly scarce, due to its leanness in valuable minerals and insufficient methods available to handle such low-grade sands. A typically low-grade titanium sand was first ground and then processed by low-intensity magnetic separation (LMS) and high gradient magnetic separation (HGMS) to recover titanomagnetite and ilmenite, respectively; as the TiO2 grade of the sand is low, the primary treatment of the sand by magnetic separations is effective, with 78.45% by mass weight of the sand discarded as tailings. The primary titanomagnetite concentrate was further ground and liberated to obtain a high-grade titanomagnetite concentrate through LMS reconcentration; the primary ilmenite concentrate was separated with spirals to remove the sterile limonite and magnetic gangues, and its concentrate was ground and liberated to achieve a high-grade ilmenite concentrate through HGMS refining. This novel process achieved an effective processing of the sand and obtained a high-grade ilmenite concentrate assaying 46.30% TiO2 with a high recovery of 57.88%, and a by-product of titanomagnetite concentrate assaying as high as 54.17% Fe.

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 200μm size.

Processing Automotive Shredder Fluff for a Blast Furnace Injection

Automotive shredder fluff is a by-product vacuumed during the shredding of end-of-life vehicles (ELV) hulks, and further refined in post-shredder lines of treatment (PST). To date in Europe the mineral part exiting the PST is mostly landfilled without regards for its potentially valuable iron content. Yet, iron could be used as part of the ore in blast furnaces, provided several issues related to the chemical composition of fluff were solved. Besides increasing iron content, several tramp elements must be curbed below tight specifications to avoid iron spoiling, furnace wall corrosion, and changes in the hydrodynamic profiles during iron reduction. The present work aims at designing such a fluff sorting process, on the basis of two representative fluff fractions properly sampled on an industrial PST. The size distributions of these fractions and the repartitions of their chemical elements are used to rationalize and compare three different sorting processes which couple sieving, wet attrition, and dry or wet low intensity magnetic separation. The best process led to an optimized iron recovery of 78.5 % corresponding to an elemental iron content of 51 %, close to the ore grade required in a blast furnace. At the global scale of ELV recycling, these results entail an increase by 4 % of the fluff recycling rate, thus helping to meet the European requirements for 2015.

Low Grade of Kyanite Ore Beneficiation Experimental Research in Xingtai

As high-grade refractories raw material，kyanite is widely used and the market demand is increasingly greater. To identify the process mineralogical properties of kyanite from Heibei so as to provide a mineralogical basis for its chemical composition, mineral constituent，ores texture and structure and so on. The results show that: the kyanite Al2O3 21.50%, SiO2 52.87%, using high intensity magnetic separation-gravity separation-flotation folwsheet. Experiments show that, the grinding fineness of -200 mush 65%, with strong intensity magnetic separation, magnetic concentrate by shaking the low intensity magnetic separation，we can get magnetite, garnet, biotite and phlogopite four concentrates, strong magnetic ore tailings consolidated by a rocking bed mud thrown first, refined through flotation, won Kyanite concentrate grading about 56.11% at a recovery of 49.90%.

Recovery of total heavy minerals from Badlands of Basanputti Village, Odisha

The badland topography of Basanputti Village, Ganjam District, Odisha, possesses red sediments. The typical red sediment deposit, on average, consists of 71.8% total heavy minerals (THM), out of which 62.1% are ilmenite. The other heavy minerals sillimanite, zircon, garnet, monazite, and pyriboles are in the order of abundance identified. In this present study, Mozley mineral separator has been used to recover THM from red sediment. Mineral separator results indicate that a product obtained contains 72.2% by weight with 94.4% THM and 95% recovery. The ilmenite concentrate recovered using dry low-intensity magnetic separator from the THM concentrate can be used in pigment industries after suitable pyrometallurgical/chemical processing methods.

Beneficiation of a Low Grade Titanomagnetite Ore in Mining Engineering

Beneficiation of a low-grade titanomagnetite ore containing 18.52%Fe and 6.65%TiO2 was conducted by dry and wet low intensity magnetic separators. Effects of different variables, such as magnetic intensity, grinding fineness and stages of separation, were investigated in details. The ore was firstly preconcentrated by a dry low-intensity magnetic separator (DLMS) at a magnetic intensity of 2500Oe, and then ground to -0.074mm 53%, followed by a wet low-intensity magnetic separator (WLMS) to recover iron minerals. An iron concentrate assaying 49.22% Fe can be obtained at a recovery of 46.23%. The concentrate was further ground to -0.074mm 70%, followed by two stages of WLMS, and a marketable iron concentrate assaying 56.24% Fe and 9.44% TiO2 can be obtained at the recovery of 42.89% and 20.69%, separately. Tailings assaying 6.48% TiO2 with a recovery of 79.31% is subject to be further recovered.

Study on Process Mineralogy and Concentrating of a Certain Kyanite Ore in Xingtai

To identify the process mineralogical properties of kyanite from Heibei so as to provide a mineralogical basis for its chemical composition, mineral constituent，ores texture and structure and so on . The results show that: the kyanite Al2O3 21.50%, SiO2 52.87%, using high intensity magnetic separation —gravity separation— flotation folwsheet. Experiments show that, the grinding fineness of -0.074mm 65%, with strong intensity magnetic separation, magnetic concentrate by shaking the low intensity magnetic separation，we can get magnetite, garnet, biotite and phlogopite four concentrates, strong magnetic ore tailings consolidated by a rocking bed mud thrown first, refined through a coarse fine two shake, shake in after a rough featured a parted, won the 60.38% grade of Kyanite concentrate and 85% grade quartz ore.

Effect of reverse flotation on magnetic separation concentrates

Reverse flotation studies on magnetite samples have revealed that the use of starch as a depressant of Fe-oxides has a hydrophilic effect on the surface of Fe-bearing silicates and significantly decreases Fe in the silica-rich stream when used in combination with an amine (Lilaflot D817M). In this study, the effect of reverse flotation on the optimization of products obtained from magnetic separation was investigated. Two different magnetic samples, zones 1 and 2, were milled to <75 μm and then subjected to low intensity magnetic separation (LIMS). The LIMS test conducted on the <75 μm shown an upgrade of 46.40wt% Fe, 28.40wt% SiO2 and 2.61wt% MnO for zone 1 and 47.60wt% Fe, 29.17wt% SiO2 and 0.50wt% MnO for zone 2. Further milling of the ore to <25 μm resulted in a higher magnetic-rich product after magnetic separation. Reverse flotation tests were conducted on the agitated magnetic concentrate feed, and the result shows a significant upgrade of Fe compared to that obtained from the non-agitated feed. Iron concentrations greater than 69%, and SiO2 concentrations less than 2% with overall magnetite recoveries greater than 67% and 71% were obtained for zones 1 and 2, respectively.

Experimental Study on the Mineral Processing of a High-Clay and Lean Hematite

The mineral processing experimental research was carried out on a high mud content lean hematite. The results showed that using the technological flowsheet of “stage grinding- low intensity magnetic separation for obtaining concentrate - high-intensity magnetic separation for discarding tailings-gravity separation(shaking table)”,a final iron concentrate with TFe grade of 65.89% ,yield of 19.35% and iron recovery of 52.32% from the raw ores with TFe grade of 24.07％ was obtained, with the first stage grinding size being 50% -200 mesh and the second stage,95% -200 mesh.

Experimental Research on Mineral Processing Technique of a Brazilian Specularite

Laboratory research on the mineral processing technique of a specularite ore from Baxi was performed, while the processes including gravity separation, low intensity magnetic separation(LIMS) -high intensity magnetic separation(HIMS)-gravity separation was adopted. The run-of-mine ore was milled till the -0.074 mm range accounts for 50% and treated through a LIMS – HIMS process, with the magnetic field strength of LIMS being 95.52 kA/m and HIMS,1.2T. As a result, an iron concentrate grading about 67.58% at a recovery of 96.21% can be obtained, which are rather good metallurgical performances. The iron concentrate with high grade also could be beneficiated by table separation, but its recovery is lower than it obtained from intensive LIMS – HIMS dressing.

Experimental Research on the Iron Separation from an Ultra Poor Iron Ore

Test was made on separating iron from a ultra-low-grade vanadium titanium magnetite ore by a process of tailing discarding at a coarser size，staged grinding and staged low intensity magnetic separation. The results show that when the raw ore is treated by permanent dry magnetic separator with low intensity magnetic separation at 12～0 mm size，qualified tailings of about 20% yield can be discarded．The coarse concentrate is grounded in two stages. With the first stage grinding size being 45% -200 mesh and the second stage，75% -200 mesh，and then treated by two stage low intensity magnetic separation．As a result，an iron concentrate with a TFe grade of 65.80%and an iron recovery of 47.74%can be achieved．

The Study on Microwave Magnetic Roasting Plus Magnetic Seperation and Acid Pickling to Enrich Nb of Low-Grade Niobium Minerals

In present article, the low intensity magnetic separation process was studied for the low-grade niobium minerals by microwave magnetic roasting. The influence of magnetic density, particle size of grinding and dispersant addition on the magnetic separation effect of sinter ore with the best magnetisability was investigated emphatically. The results show that the iron recovery was decreased and the iron grade increased gradually with decreasing the magnetic density and particle size of grinding. The magnetic separation result of sinter ore was optimal under the magnetic density of 80KA / m and the grinding grain-size of 33 μm. Fine grinding can effectively make Fe separated from Nb, especially when the dispersant(industrial alcohol) was used in the process of magnetic separation , resulting in the improvement of the grade of iron from 57.2% to 60.5% and enrichment of Nb in the tailing ore(the grade of Nb was 5.01%). After the acid pickling of tailing ore containing Nb, the grade of Nb in the extract was improved to 12.36%, which was enriched four times more than that of low-grade niobium ore before microwave magnetic roasting.