magnetic separation for ore

iron ore magnetic separation

In the West, capitalists have expended many millions of dollars developing the low-grade porphyry ores of copper. Half a dozen of these great enterprises have proved to be wonderful commercial successes. They have demanded improved crushing and concentrating machinery and consequently it has been developed. Many improved methods, cheap power, superior business organization, all these have contributed to this success, but the main feature is the handling of the material in enormous quantities, on a manufacturing scale. The mining chance of striking it rich has been eliminated by the manufacturing certainty of handling large quantities of material of known value, which while of relatively low grade, is available in large tonnages, assuring a supply for many years run of the mill. Then the returns on the money invested are sure.

The concentration of low-grade magnetic iron ores, separating the magnetite crystals from the gangue by the use of magnets, is a field of work in which the lessons taught by the development of the porphyry coppers can be studied to advantage. Large-scale operations, and the liberal expenditure of enough money at the start to insure the most economical operations, are the means of securing the desired results.

The problem is to utilize millions of tons, and we may safely say billions of tons, of now worthless iron-bearing rock and to produce from it 10,000,000 to 20,000,000 tons per year of high-grade ore carrying 60 per cent, iron or higher; to take the lean material as found in nature, varying widely in iron content, and bring it up to a uniform standard of shipping ore. At present these ores are mined carrying from 25 to 50 per cent, iron, and the shipping product is brought up to 60 or 65 per cent. Fe. If future economies of operation make it possible to extend this process so that 15 per cent, iron in the crude ore can be treated as a commercial success, the additional tonnage available will be enormous. A 15 per cent. Fe crude ore raised to 60 per cent. Fe concentrate with 5 per cent.

Fe loss in tailings would require 5.5 tons of crude for 1 ton of concentrates. The cost of crushing and concentration can be brought down to 12 c. per ton crude or possibly to 10 c., and the cost of quarrying on a large scale, probably 40 c., would be low enough to leave a profit even now. There are mountains of gabbro rock in the Adirondacks that will average 15 per cent, iron in the form of magnetite crystals of good size, say 1/8 to 1/16 in., but the concentrate would also carry some titanium.

A thorough examination of some of the iron-ore properties and the knowledge acquired by development of extensive underground workings makes it possible to make quite definite estimates of tonnage available in certain areas, which show very large reserves.

F. S. Witherbee in his paper read before the American Iron and Steel Institute last October gave an estimate of 1,100,000,000 tons of crude magnetic ore above 30 per cent. Fe available for concentration in the Adirondack region alone, not including any titaniferous ores except the one deposit at Lake Sanford. He practically confined his estimate to the area of the iron-bearing gneisses which surround the central core of later eruptives, the anorthosites and gabbros, in which the titaniferous ores are found.

There are also in New Jersey and southeastern New York large areas that give conclusive evidence of vast amounts of non-titaniferous magnetites. The map accompanying the report of the State Geologist of New Jersey, year 1910, shows the area of iron-bearing gneiss rocks running northeast and southwest across the State about 18 miles wide by 50 miles long, from Phillipsburgh to Greenwood Lake. In this area are located by name 366 magnetite mines that have been worked more or less. There are also 24 limonite and 8 hematite mines. These lenses may easily be capable of producing an average of 1,000,000 tons each and there are probably double the number listed not opened up. Here we have 900 sq. miles of iron-bearing gneisses in New Jersey, or more than in the Adirondack region, with nearly as much more additional in southeastern New York, reaching from the New Jersey line across the Hudson at Fort Montgomery and extending to Brewsters.

Mr. Witherbees method of computation estimated 20 ft. thickness of ore over 10 per cent, of the surface area. He afterward cut the estimate, in half to be conservative, which was equivalent to 10 ft. thickness of ore on one-tenth of the surface. This would give 2,700,000 tons per square mile or on 900 sq. miles in New Jersey 2,300,000,000 tons, with a goodly area in New York to-fall back on to make up deficiencies.

Magnetic ore is found quite widely distributed, in Canada, Minnesota, California; New Mexico, New York. New Jersey, Pennsylvania, North and South Carolina, Tennessee. A detailed study of these deposits might be an interesting subject for the Bureau of Mines to follow up.

Some time in the, year 1887 my attention was called to the magnetic separation of ores. At that time Edison was experimenting with his deflecting magnet and the Wenstrom, a Swedish machine of the drum type, was in use. The Conkling machine, which was also on the market, was the forerunner of the modern belt machine, but the magnetic attraction came from a single magnetized plate.

My first experiment was with Port Henry old-bed ore, which I crushed to pass through 1/8 in. mesh, and then ran through an old-fashioned fanning-mill, such as are used on farms. I had better results than those obtained by Mr. Edison with his deflecting magnet. I then made a trial of the Conkling idea but found that the magnetic plate picked up a large part of the gangue with the ore, so that the ore had to be sized and fed very slowly to get good results. The same trouble was experienced with the Wenstrom machine.

I then made a small machine, substituting common horseshoe magnets , for the magnetic plate of the Conkling machine. Since the magnets were of north and south polarity the ore turned end for end in moving from one pole to the nextnot only the loops of ore and gangue but each individual piece turning. In this way the gangue was allowed to drop out, the ore was held, passed on to the next magnet, and so finally cleaned of the non-magnetic rock.

However, as I was not an electrical engineer, I went to a friend, Clinton M. Ball, explained the operation of the machine, and told him that if he would make electromagnets of sufficient size and power, of alternating poles, I thought they would be a great improvement over anything previously used. Mr. Ball made the magnets, a small machine was built (shown in Fig. 2), and taken to the Benson mines, where about

The small machine was of the belt type. Mr. Ball soon after designed a drum-type machine, and later a double-drum machine in which a three-part separation was made. There are now magnetic machines of many types, but the majority use the alternating pole magnets.

Mr. Palmers machine is an interesting example of an early crude use of an important scientific principle. It was simple and primitive in the extreme, consisting primarily, of a row of horseshoe magnets spiked around a log, like the spokes of a wheel. Finely crushed crude ore was allowed to slide through a wooden trough underneath the magnets, which were rotated by a crank attached to their supporting log. As the magnets rotated, they dipped into the trough, the good ore became attached to them and was lifted up. It was then transferred to another trough, set above, by employing the simple device of a broom wielded by a husky Irishman.

The number of so-called magnetic separators for which patents have been taken out has been so large that it would be a waste of time even to try to enumerate, them. Many of them were mere toys and a number were mechanical monstrosities. The belt and drum machines of the Ball and Norton patent have accounted for 90 per cent, of magnetic concentration by the dry process; while the wet magnetic process has been entirely monopolized in this country by the Grondal-type machine. There are no patents today controlling magnetic separation, and there is no longer any chance for any now or startling discoveries in this line.

The first magnetic separator that I constructed was of the belt type. It was operated with a feed belt running 125 ft. per minute, while the take-off belt ran 250 ft. per minute. I wished to make a careful test of the capabilities of the machine when working on an ideal material, so I prepared a special mixture for the purpose. This consisted of crushed white marble, washed and sized between 1/8 and 1/20-in. mesh; mixed with iron ore of the same size in a proportion of 2 parts marble to 1 part iron. It was evident that the particles of iron ore and marble would not be attached to each other, since the, mixture was purely artificial. This mixture was then fed to the machine in a stream in. deep. The separation was almost perfect, giving an iron product over 99 per cent. pure. In this way, the possibility of a complete separation was conclusively demonstrated. In actual practice, however, such thorough preparation of material is impossible, and, owing to the difficulty of properly preparing the ore, there are some cases where separation cannot be made a commercial success.

The magnetic iron ores found in different localities vary widely, not only in their iron content, but also in their physical structure. The ores from the various districts require, consequently, radically different treatment.

In the first place, bodies of ore differ widely in crystallography. For example, the ores of the Champlain Valley are more coarsely crystalline than the ores of New Jersey, the Benson mine, or the Cornwall ore bed. Obviously the mill treatment of these ores cannot be the same. Among other things, ore containing the coarser crystals would not require to be crushed to so fine a size as ore of the Cornwall type. It is very important to find the exact size at which any particular ore is most economically separated, and this size can easily be determined by experimental tests in a suitable laboratory. Moreover, the degree of fineness to which the ore must be crushed determines the process of separation to be employed. An ore which must be crushed to 1/8 in., 1/16 in., or lower will require the wet method of separation, while for larger sizes the dry method can be most profitably employed. The exact size that determines the method to be used is also somewhat dependent on the amount of moisture contained. Quite fine sizes can be separated if perfectly dry and fed in a thin film, but the dust problem is then somewhat difficult to deal with.

The largest development in the iron-ore industry, using magnetic concentration, is at the plants of Witherbee, Sherman & Co. at Mineville, N. Y., where about 1,200,000 tons of crude ore were mined and separated in 1916. The dry process of separation is used. The Chateangay; Ore & Iron Co., at Lyon Mountain, N. Y., the Empire Steel &

Iron Co. and the Ringwood Co. in New Jersey, also use the dry process successfully. The Grondal wet separators have been recently installed at the Benson mines in New York. The largest development of the, wet process in this country is on the Cornwall ore at Lebanon, Pa. This work is in charge of B. E. McKechnie, who is the highest authority on the wet process.

In the practical application of magnetic separation the most vital part is the preparation of the ore. It must be crushed so that the crystals of magnetite, or groups of crystals, are sufficiently freed from rock to bring the percentage of iron up to the standard set for shipping ore. On the other hand, it must not be crushed too fine, if it is possible to avoid it, otherwise the blast does not pass through readily in the furnace, or the ore blows over the top.

If the material going to the separators is sized, the strength of the magnets, can be adjusted to pick up the ore of more nearly uniform quality, but a separation can be made without very close sizing.

The pulley-type machine (Fig. 4) has a full circle of magnets which revolve with the drum. The magnets are wound to carry more-current than the-drum machine and will attract any lean ore, throwing off pure rock or tailings.

The drum and pulley machineswill handle 30 to 50 tons per hour and are used together. The drum picks out any ore, as heads, rich enough for shipment. The pulley throws out rock lean enough to discard; what is left as middlings is crushed to about half its size and passed to machines treating finer sizes.

The belt-type machine (Fig. 5) is used when the ore is reduced to -in. or below. The magnets are open to the air, so keep comparatively cool and are easily inspected. Since the magnets of the belt machine lift the ore from the feed belt, the gangue is less likely to be held in suspension and a cleaner concentrate is insured. In the triple-deck machine shown in Fig. 5 the two top machines make heads and the bottom one makes tailings, and middlings to be reground.

If fine grinding is necessary to separate the crystals of magnetite from the gangue, wet separation is indicated. In this case treatment by sintering, or other processes, to agglomerate the ore is also required. The sintering process solves another difficulty by removing sulphur. Low iron and high sulphur content are handicaps which can now be both overcome by the combination of magnetic concentration and sintering.

The accompanying flow sheets of mill No. 3 (Fig. 6), mill No. 4 (Fig. 7), and mill No. 5 (Fig. 8), of Witherbee, Sherman & Co. at Mineville, N. Y., show arrangements for treating, three different ores. The richness of the ore determines at what size the first separation can be made.

The ore must be very dry in order to secure freedom of motion between the particles, or poor separation will result. This condition allows the very fine particles to escape as dust. No system of fans or other arrangements for eliminating or controlling this dust has been developed which can be successfully operated at a cost not prohibitive on this ore.

Owing to the tendency of the fine particles of talcy gangue to cling to the magnetic pieces, it was found impossible to raise the iron constant above 52 per cent, when separating the average grade of Cornwall ore. This fact is demonstrated by washing concentrates from the dry magnetic separation, when the iron content was easily raised from 52 to 58 per cent. This suggested using a combined process of dry magnetic separation and of washing the magnetic product in some such apparatus as the Dorr classifier.

The same or better results could probably be obtained by a wet magnetic separation. This process would eliminate the cost of drying, the dust problem and should give a higher recovery of iron, due to the fact that a certain amount of iron would be lost in the slime from washing of dry concentrates. In the wet magnetic separation this washing is carried out in a strong magnetic field, which greatly reduces the loss from this cause.

In connection with the results obtained from the experimental wet magnetic separator constructed for investigating the wet process of magnetic separation of Cornwall ore, attention is called to the following points:

It is evident that in the separation of any ore by magnetic or other forces, the ore must be crushed sufficiently fine to free the valuable minerals from the gangue, and also that the degree of fineness required in the crushing depends upon the physical characteristics of the ore. As it is impractical to carry the crushing far enough to free all the mineral from the gangue, there will be a certain percentage of attached particles or middlings consisting of both mineral and gangue.

In the case of magnetic separation, these attached particles may go either as concentrates or tailings, depending on the strength of the magnetic field and the ratio by weight of magnetic to non-magnetic material in each. From this it follows that the stronger the magnetic field, the lower in iron will be both the concentrates and tailings product, due to a larger quantity of attached particles being attracted to the magnets. The reverse also holds true, that, the lower the current, the higher in iron will be both the concentrates and tailings as fewer attached particles will go to the concentrates and more to the tailings.

The richer the crude ore, the higher will be the grade of concentrates and the higher will be the iron content in the tailings. This is due to the fact that the rich ore carries a greater proportion of rich particles and a smaller proportion of rock. The grade of concentrates is raised, due to the smaller percentage of attached particles, while the percentage of iron in the tailings is greater, because of the smaller amount of clean rock present to balance the small quantity of magnetic material entering the tailings.

Assuming that the amount of magnetic particles dropped by the separator is a nearly constant quantity, a higher percentage of recovery of iron is obtainable from a rich ore than from a leaner ore as the percentage of iron lost is evidently less.

The wet magnetic separator constructed for these experiments is a drum-type machine, constructed on the Ball-Norton principle. It consists of a number of stationary electromagnets, of alternate positive and negative polarity attached radially to a central shaft. About these magnets revolves a non-magnetic, water-tight drum, which carries a thin rubber belt.

In practice the magnets do not extend the entire circumference of the machine, but a gap is left between the points of feeding and delivery of concentrates. In this machine which was built for experimental work, any desired number of magnets could be cut out by short-circuiting the current around them.

Arrangement 1.The revolving drum drives the thin rubber belt which covers the face of the drum and passes over pulleys. Ore and water, or pulp, are fed by a launder or feed sole in such a manner that the feed is thrown against the moving belt. The magnetic particles are held to the drum, while the non-magnetic material falls into the tank and is drawn off. As the magnetic material held against the belt passes through the water, the influence of the alternating polarity of the magnets is to cause the magnetic particles to take a rolling action, which allows any entrapped gangue to fall out. As the drum further revolves, the magnetic concentrates are lifted out of the water and carried up the belt and around the pulley, where they are washed off by a spray of water.

In practice on Cornwall ore, it was found that a certain amount of very fine gangue was carried by the water into concentrates. They were, therefore, led to a classifier consisting of an inverted pyramid or tank, the bottom of which was fitted with a small hole and a connection above this hole for supplying clean water under slightly greater head than the depth of water in the tank. This water supply was regulated to furnish all the water required to supply the hole or the spigot and to furnish a slight raising current against which the heavy magnetic particles would fall but the very fine gangue could not, but would escape over the edge with surplus water.

Arrangement 2 was similar to 1 except that the water level in the tank was lowered until it was below the drum. This was done in an effort to reduce the amount of dirty water carried over the concentrates. The separator failed to make a separation operated in this manner, due to the fact that the surface tension of the water on the drum caused this water to act as a blanket, which did not allow the non-magnetic material to fall out.

In arrangements 3 and 4, the motion of the drum was reversed and the idler pulley removed. The feed sole was placed above to feed the pulp in the direction of travel of the belt. The tailings were to be removed at the tank and the concentrates, carried past the division board placed under the last magnet were to be removed by the spray of water. Due to the surface tension of the water, no separation took place above the water level. The separation accomplished beyond this point was destroyed by currents set up in the water by the rotation of the drum.

It should be noted that 9 per cent, represents non-magnetic iron, or that about 75 per cent, of the iron occurring in this tailings sample is non-magnetic and cannot be charged to the inefficiency of the separation.

Crude..38.30 per cent, total Fe, 33.64 per cent. Fe as magnetite. Concentrates..58.40 per cent, total Fe, 55.97 per cent. Fe as magnetite. Tails10.20 per cent, total Fe, 2.17 per cent. Fe as magnetite.

The following reports show results of samples tested to determine treatment required and quality of concentrates that could be expected. These tests were run on a regular mill size separator and the results could be duplicated in actual practice. The separate determinations of iron as magnetite, and total iron, were made so that the difference between the two would show the amount of iron combined as silicates in hornblende and other gangue minerals.

307 lb. crude ore was crushed to pass 1/8-in. screen; separated, by screening, into two sizes, on 16 and through 16-mesh. Through 8 on 16-mesh 132 lb., through 16, 175 lb. 8-16 size, treated on belt machine using 3, 4, 5 amp. and finally with 4 amp. for heads. Then 12 amp. for midds and tails.

Crude 224 lbFe Heads 115.Fe 66.15, P 0.005 Tails 108.Fe 3.00 General crude 307 lb.Fe 30.85 P 0.008 General cone. 135Fe 65.60, P 0.005 General tails 171..Fe 3.27

Note.Owing to the iron being present in very small crystals it is necessary to crush this ore to at least 1/8-in before separation, but since the ore is extremely brittle this is easily accomplished with little power.

Note.In order to reduce the iron in the tailings finer grinding through 16-mesh will be necessary at the last stage making a three-part separation on the through 16 size and retreating resulting midds.

The demonstration of the dry process of magnetic separation is the result of 14 years work at Mineville, N. Y. Witherbee, Sherman & Co. have now in operation three mills having a combined capacity of 6,000 tons per day of crude ore. The Empire Steel & Iron Co. and the Ringwood Co. have demonstrated what can be done with New Jersey ores. The Ringwood Co. has also worked out a dry process of jigging for their tailings to recover the martite, which is non-magnetic. Martite is a hematite in composition, but is very similar in appearance and crystallization to the magnetite. Some of the magnetic ores have varying amounts of martite mixed with the magnetite.

The known and partially developed orebodies of New York and New Jersey could, if equipped with the best modern mining and milling machinery and using the best methods, produce at the present time 25,000 tons of 60 per cent, iron ore per day. This can be delivered for an average freight charge of $0.75 per ton from mill to tidewater. The operating cost of production should reach the dollar rock ideal of the Lake Superior Copper region, and the cost of mining and milling 1 ton of crude ore should be about $1 for underground mining when handled in large quantities.

The ratio of concentration would be 2 tons of crude per ton of concentrates for an average. There are reserves of magnetic ore sufficient to double the above production, and then last probably 100 years.

pre-separation technology for low-grade magnetic ore

With the grade of crude ore increasing declining, pre-separation technology has become an important means of increasing productivity and economic efficiency. Pulley for large-block magnetic ores, box dry magnetic separators and magnetic separators with rotating magnetic field can provide technical solutions for pre-separating ores at various particle sizes ranging 0-400mm.

CT1627(1600x2700)pulley for large-block magnetic ores was applied in Chinas Hebei Province, with a separation belt of 2500mm in width and a capacity of 4500t/h and -350mm separation particle size.

CT1424(14002400)magnetic pulley was applied in Chinas Shaanxi Province, with a separation belt of 2000mm in width, a capacity of 600-800t/h and 50-150mm separation particle size.

CTF series box dry magnetic separator was applied for -15mm ore pre-separation, with a capacity of 80t/h in a plant in Shandong, with the tailings rate about 15%, iron ore grade improved by 3-5%, and the recovery rate over 90%.

magnetic separation in the mining industry - mainland machinery

One of the greatest challenges facing the mining industry is the separation of unwanted material generated by the extraction process from the valuable material. Mining, whether done through open seam or underground means, creates a huge amount of waste product in the form of worthless or low value minerals and unusable man-made materials. These materials can be extremely difficult to separate from the valuable materials miners are after. Perhaps the most efficient way of separating these materials is through magnetic separation.

Magnetic separation machines consist of a vibratory feeding mechanism, an upper and lower belt and a magnet. The bulk material is fed through the vibrating mechanism onto the lower belt. At this point, the magnet pulls any material susceptible to magnetic attraction onto the upper belt, effectively separating the unwanted metals from the rest of the bulk.

Magnetic separation has been used in the mining industry for more than 100 years, beginning with John Wetherills Wetherill Magnetic Separator, which was used in England in the late nineteenth century.

Magnetic separation is most commonly used in the mining industry to separate tramp ore, or unwanted waste metals, from the rest of the bulk material. Tramp ore typically consists of the man-made byproducts created by the mining process itself, such as wires from explosive charges, nuts and bolts, nails, broken pieces from hand tools such as jack hammers and drills or tips off of heavy duty extraction buckets.

Magnetic separation machines are usually placed at the beginning of a mines materials processing line to remove tramp ore before it can cause harm to downstream equipment such as ore crushers and conveyor belts, which can be easily damaged by metal shards or other sharp objects.

The type of magnetic separator used by a mine depends on what material they are extracting and how much tramp ore is generated by their process. As a result, separators of different magnetic flux, or power, can be used. There are 2 types of magnetic separators; electromagnetic and permanent.

Electromagnetic separators generate a magnetic field by switching power from alternating current to direct current. Electromagnetic separators are useful for removing large pieces of tramp ore from the bulk material. These separators are typically suspended over a conveyor belt and draw the unwanted material upward. Electromagnetic separators are easy to clean as removing the tramp ore that they separate from the bulk is as simple as turning off the power that creates their magnetic field.

Permanent magnets consist of materials that generate their own magnetic field. Though not as powerful as electromagnetic separators, permanent magnets are better at attracting strongly magnetized materials such as nickel, cobalt, iron and some rare earth metals. Some permanent magnets are now being made with rare earth metals that have the ability to attract even stainless steel, which is typically not susceptible to magnetic pull. In order to clean permanent magnets, a stainless steel scraper must be used to remove any metal parts from the magnets surface.

Magnetic separation definitely is one of the most important parts of this process. I think magnetic separators are often taken for granted when it comes to processing, whether that processing is in mining or in food processing. Many people dont even know the work that goes into making food safe or mining materials pure.

magnetic separation for mining industry magnetense


Contact us to find out how Magnetense can help you overcoming system and productivity challenges. We offer complimentary video, telephone and chat conversations to help you clarifying your needs in order to present you with the most cost-efficient solutions.

This type of magnetic separation machine is used in wet separation processes for smaller than 1,2 mm ( 200 mesh of 30-100 %) of fine grained red mine (hematite) limonite, manganese ore, ilmenite and some kinds of weakly magnetic minerals like quartz, feldspar, nepheline ore and kaolin in order to remove impurity iron and to purify them.

This type of Vertical Ring High Gradient Magnetic separator uses a wholly sealed oil cooling circulating device: through this device process water goes through a oil-water heat exchanger used to remove the heat generated by the magnetic separators coils. The windings coil generates a magnetic field through the upper and lower yokes: a vertical ring can rotate according to the required direction. When the magnetic separator is working, the hopper is fed by the feeding tube with a pulp that flows through the rotating rings, along with the gap of upper magnetic poles. An induction magnetic matrix composed by high permeability stainless steel rods generates an high gradient magnetic field.

Pulp enters in contact with the lower part of the rotating ring and the magnetic matrix surface attracts magnetic particles. Due to the ring rotation the magnetic minerals are transferred to the nonmagnetic area of the ring and are discharged to the upper hopper by the water flow. The non magnetic particles are moved down to the lower hopper following the gap of the lower magnetic pole and the magnetic separation of magnetic minerals is completed. At this point the pulsating box is activated causing the pulp shaking up and down in order to remove impurities and improving the concentration of the pulp.

The HMF electromagnetic filters are used in wet process separation of para-magnetic minerals found in quartz, feldspar,silicates, calcium carbonate and kaolin. The flow-rates are engineered in accordance with customer requirements.

Most older generation magnetic belt conveyors were fitted only with ferrite magnets. Our Overbelt Shark model has a specific combination of ferrite and neodymium magnets: what is the advantage for you?

PLEASE NOTE: In this industry it is common practice adopted by some manufacturers to guarantee magnetic performances only on the base of approximated calculations or under non-operating conditions. In this regard Magnetense is different and the performance stipulated above are measurable and documented.

To provide an additional wear resistance, we reinforced the side structures (sometimes severely stressed by the continuous use of grinding machines or by extreme working conditions or by weather conditions) and the diameter of the shafts (some customers told us they have even exaggerated).

With a diameter of 300 mm and a working height of 1500 mm, our tigers have a higher capacity than lower heights and diameters machines: this feature, combined with the exceptional magnetic power (12,310+ Gauss in contact wit the surface), allows our magnetic pulley to practically catch almost any magnetic particle or paramagnetic mineral.

Rollers 100 mm to 300 mm diameter with working heights varying from 1.000 to 1.500 mm.can be installed in our machines. In order to meet specific customers requests, MAGNETENSE can produce rollers larger than 300 mm diameter.

Contact us to find out how Magnetense can help you overcoming system and productivity challenges. We offer complimentary video, telephone and chat conversations to help you clarifying your needs in order to present you with the most cost-efficient solutions.

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dry magnetic separation of iron ore of the bakchar deposit - sciencedirect

Currently, the development of iron ore of the Bakchar deposit (Tomsk region) is considered promising because of the extremely large reserves of iron ore. Ores of this deposit are related to the high-grade type and expected to have a magnetic concentration for iron extraction. The main task of magnetic separation is to increase the total iron content in concentrates to a value which allows its further metallurgical processing. Ferruginous ore particles have a rounded shape that facilitates a separation process. The paper considers the influence of technological parameters on the magnetic concentrate yield and recovery rate of iron-containing fractions.

magnetic separation and magnetic properties of low-grade manganese carbonate ore | springerlink

The relation between the magnetic separation behavior and magnetic properties of a low-grade manganese ore was analyzed before and after treatment by direct reduction with coal. It was found that raw ore with an initial average grade of 10.39% Mn and consisting of diamagnetic and paramagnetic minerals can be concentrated by high-intensity magnetic separation to produce a salable product with a grade of 22.75% Mn and a recovery of 89.88%. In contrast, direct reduction of the ore results in a new Mn-Fe oxide phase formed with a combination of ferromagnetic and paramagnetic properties, thereby increasing the magnetic susceptibilities of the ore by almost two orders of magnitude. The grade of Mn for the roasted ore could only be concentrated to 15.49% with a recovery of 66.67%. Therefore, it is concluded that the low-grade manganese ores with antiferromagnetic and paramagnetic (or diamagnetic, but not strongly ferromagnetic) properties could be efficiently beneficiated via high-intensity magnetic separation.

The authors are grateful to Prof. X.J. Li and Dr. D. Yang for helpful discussions and critical comments. This work was financially supported by geological survey projects (Nos. 12120113087100 and 12120113087000) of the China Geological Survey Bureau.

manganese ore magnetic separator

Gravity separation and magnetic separation can be involved for manganese upgrading. Gravity separation is more commonly used in manganese beneficiation with its low plant investment and low operation cost. However for some manganese ore of too fine inlay or small density difference between manganese and its attached gangue, gravity separation can not work, magnetic separation or floatation separation can be considered. In this situation, magnetic separation can be the main beneficiation way for manganese ore because floatation separation needs large investment and high operation cost and it is hard to be accepted by the miner. Intensity magnetic separation can be the core upgrading method for this kind of manganese ore. The following is about Forui manganese magnetic separator.

magnetic separation studies for a low grade siliceous iron ore sample - sciencedirect

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 200m size.