Wet Low-intensity Magnetic Separation Research Articles

Direct measurement of internal material flow in a bench scale wet low-intensity magnetic separator

In this work an ultrasound-based measurement method is used for monitoring suspension velocity and build-up of magnetic material inside a wet low-intensity magnetic separator, a process used e.g. in beneficiation of magnetite ores. Today the only available option is to monitor material transport between unit operations; i.e. flow rate, solids concentration, and particle size distribution of suspension flow in pipes are measured online using standard equipment.An acoustic backscatter system is fitted to the tank of a separator, and used to monitor the internal flow. A method called ultrasonic velocity profiling is used to capture internal velocity profiles. Simultaneously, the backscatter signal intensity is used to get indications about local solids concentration of the flow, and build-up of magnetic material. The methods are evaluated in realistic conditions, where the effect of varying factors relevant to machine performance is investigated. The included factors are; the slurry feed rate, the slurry solids concentration, the magnet assembly angle, and the drum rotational speed.The presented method gives useful information about the internal material flow inside the separator. The velocity measurements capture the, sometimes complex, internal flow patterns, for example the presence and velocity of a recirculating flow in the dewatering zone. Additionally, keeping a balanced material loading in the concentrate dewatering zone is important to separator performance. Using the signal backscatter intensity it is possible to qualitatively monitor this material loading. Generally these direct measurements can aid in improvements to machine design, process optimization, and process control.

Mineralogical and Beneficiation Studies of a Low Grade Iron Ore Sample

Investigations were carried out, to establish its amenability for physical beneficiation on a low grade siliceous iron ore sample by magnetic separation. Mineralogical studies, with the help of microscope as well as XRD, SEM–EDS revealed that the sample consists of magnetite, hematite and goethite as major opaque oxide minerals where as quartz and kaolinite 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. Dry beneficiation studies by Permaroll separator indicated that it is possible to get a product with 60.2 % Fe at 22 % weight recovery. It is possible to get an over all concentrate with 54 % Fe at 32.4 % weight recovery by combination of size reduction followed by LIMS and WHIMS.

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%.

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.

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.

Magnetic separation of coal fly ash from Bulgarian power plants

Fly ash from three coal-burning power plants in Bulgaria: 'Maritza 3', 'Republika' and 'Rousse East' were subjected to wet low-intensity magnetic separation. The tests were performed at different combinations of magnetic field intensity, flow velocity and diameter of matrix elements. It was found that all parameters investigated affected the separation efficiency, but their influence was interlinked and was determined by the properties of the material and the combination of other conditions. Among the fly ash characteristics, the most important parameters, determining the magnetic separation applicability, were mineralogical composition and distribution of minerals in particles. The main factors limiting the process were the presence of paramagnetic Fe-containing mineral and amorphous matter, and the existence of poly-mineral particles and aggregates of magnetic and non-magnetic particles. It was demonstrated that the negative effect of both factors could be considerably limited by the selection of a proper set of separation conditions. The dependences between concentration of ferromagnetic iron in the ash, their magnetic properties and magnetic fraction yields were studied. It was experimentally proved that, for a certain set of separation conditions, the yields of magnetic fractions were directly proportional to the saturation magnetization of the ferromagnetic components of the ash. The main properties of typical magnetic and non-magnetic fractions were studied.

STATISTICAL DESIGN APPLICATION AND ANALYSIS OF SEPARATION EFFICIENCY IN DAVIS TUBE TESTER

Wet low intensity magnetic separation studies for a synthetic binary mixture of magnetite and quartz were carried out. The variables studied were particle size, magnetic field intensity, and wash water rate. Experiments were carried out using 23 full factorial designs. The main and interaction effects on the separation efficiency were evaluated using Yates' analysis. The optimum magnetic separation conditions were calculated by the method of steepest ascent. A concentrate with 98.9% magnetite at 87.2% component recovery and 86.3% separation efficiency was obtained at following optimum conditions: 200 µm particle size, 3190 Gauss magnetic field intensity, and 402 cm3/min wash water rate.

Recovery of Magnetite from Leached Laterite-residue by Magnetic Separation

In order to improve the grade of iron, upgrading of laterite ore was conducted using wet low intensity magnetic separator. The ore was treated through selective reduction followed by sulphuric acid leaching to recover nickel while iron remained in residual solid. The Vibrating Sample Magnetometer measured the magnetic properties of the ore, as a fundamental of magnetic separation. Magnetic separation was carried out using a Davis Tube Tester. The effect of pretreatments on the magnetization and magnetic separation were investigated.The results showed that the ore has similar magnetic property with goethite. The heating of the ore at 673 K did not improve significantly on its properties whether goethite changes to magnetite. However, the reduction treatment increased the magnetic properties of the ore due to the formation of magnetite. The magnetic susceptibilities of the original, heated and reduction treated laterite ores were 2.36×10−5, 2.18×10−5 and 2 357×10−5 emu/g, respectively. The correlation between magnetite content and magnetization of the magnetic concentrate was showed in a linier equation, which could be used for the prediction of magnetite content in the sample based on its magnetization. Magnetic separation was applied only to recover iron from the laterite ore after being treated by the selective reduction in which magnetite was produced. About 93.9% of magnetite was upgraded from the laterite ore with 90% of recovery was obtained. The relatively high iron content in the magnetic concentrate indicated a potential use as raw material for iron making.

Behaviour of manganese oxides during magnetising reduction of Baharia iron ore by CO–CO2 gas mixture

High manganese containing iron ore samples were isothermally reduced with a CO–CO2 gas mixture at 600–1000°C. The course of reduction was followed by a weight loss technique. The influence of reducing gas composition and temperature on the reduction kinetics was investigated. The different phases formed during reduction were identified by X-ray phase analysis, while their structures were microscopically examined. The reduced samples were magnetically tested by means of a Davis tube tester. The effect of grain size, drum speed, and cleaning conditions on the efficiency of magnetic separation was studied using a Box-Mag wet low intensity magnetic separator. The separation efficiency was determined by analysing total iron, manganese, and acid insoluble contents in both magnetic and non-magnetic fractions. Best testing results were obtained on separation of the sample reduced with 80CO–20CO2 (vol.-%) at 800°C. The optimum grain size for magnetic separation is below 0·15 mm while that of the drum speed is 100 rev min-1 . The cleaning of the magnetic fraction increases the iron content and decreases the manganese and acid insoluble contents.

5354345 Reactor arrangement for use in beneficiating carbonaceous solids; and process

Flotation is the most effective solution, both technologically and economically, when upgrading iron concentrates. Research regarding iron ore flotation began in 1931, demonstrating that reverse cationic flotation is a very efficient method for beneficiating oxidised iron ores. This method can also be applied to reduce the silica content in magnetite concentrates obtained using wet low-intensity magnetic separation. Several studies describing the processing of iron ores via reverse cationic flotation are reviewed. The predominate role of the pulp mineralogy, as well as the type and molecular structures of the collectors and depressants, on flotation is discussed critically. The results concerning the role of the silicate mineralogy on the choice of reagents and flotation processes are also discussed. Further development of the reverse cationic flotation of iron ores requires a more detailed consideration of the nature of iron-bearing gangue minerals and the application of original approaches for the selective removal of these species.

5234111 Flotation machine: Mikhail Zlobin, Georgy P Permyakov, Alexandr A Nemarov, Viktor M Metsik, Jury V Medetsky, Nikolai T Taraban, Mirny, Union Of Soviet Socialist Republics

Flotation is the most effective solution, both technologically and economically, when upgrading iron concentrates. Research regarding iron ore flotation began in 1931, demonstrating that reverse cationic flotation is a very efficient method for beneficiating oxidised iron ores. This method can also be applied to reduce the silica content in magnetite concentrates obtained using wet low-intensity magnetic separation. Several studies describing the processing of iron ores via reverse cationic flotation are reviewed. The predominate role of the pulp mineralogy, as well as the type and molecular structures of the collectors and depressants, on flotation is discussed critically. The results concerning the role of the silicate mineralogy on the choice of reagents and flotation processes are also discussed. Further development of the reverse cationic flotation of iron ores requires a more detailed consideration of the nature of iron-bearing gangue minerals and the application of original approaches for the selective removal of these species.