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ball mills 30 tonnes per hour china

As magnetic separators progress toward larger capacity, higher efficiency, and lower operating costs, some subeconomic iron ores have been utilized in recent years. For example, magnetite iron ore containing only about 4% Fe (beach sands or ancient beach sands) to 15% Fe (iron ore formations) and oxidized iron ore of only about 10% Fe (previously mine waste) to 20% Fe (oxidized iron ore formations) are reported to be utilized. They are first crushed and the coarse particles pretreated using roll magnetic separators. The magnetic product of roll magnetic separators may reach 25–40% Fe and then is fed to mineral processing plants

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magnetic separator - an overview | sciencedirect topics

As shown in Figure 5, slurry is fed from the top of an inclined screen in a low-intensity magnetic field, with the mesh size of screen sufficiently larger than those of particles in slurry. As the slurry flows down the above surface of screen, magnetic particles agglomerate with the size of agglomerations increasingly growing and roll down as magnetic concentrate at the lower end of screen. The less- or nonmagnetic particles pass through the screen as tailings. Figure 5 shows the operation of screen magnetic separators for cleaning of magnetite

Commercial magnetic separators are continuous-process machines, and separation is carried out on a moving stream of particles passing into and through the magnetic field. Close control of the speed of passage of the particles through the field is essential, which typically rules out free fall as a means of feeding. Belts or drums are very often used to transport the feed through the field

As discussed in Section 13.4.1, flocculation of magnetic particles is a concern in magnetic separators, especially with dry separators processing fine material. If the ore can be fed through the field in a monolayer, this effect is much less serious, but, of course, the capacity of the machine is drastically reduced. Flocculation is often minimized by passing the material through consecutive magnetic fields, which are usually arranged with successive reversals of the polarity. This causes the particles to turn through 180°, each reversal tending to free the entrained gangue particles. The main disadvantage of this method is that flux tends to leak from pole to pole, reducing the effective field intensity

magnetic separator - an overview | sciencedirect topics

Provision for collection of the magnetic and nonmagnetic fractions must be incorporated into the design of the separator. Rather than allow the magnetics to contact the pole-pieces, which then requires their detachment, most separators are designed so that the magnetics are attracted to the pole-pieces, but come into contact with some form of conveying device, which carries them out of the influence of the field, into a bin or a belt. Nonmagnetic disposal presents no problems; free fall from a conveyor into a bin is often used. Middlings are readily produced by using a more intense field after the removal of the highly magnetic fraction

Conventional magnetic separators are largely confined to the separation or filtration of relatively large particles of strongly magnetic materials. They employ a single surface for separation or collection of magnetic particles. A variety of transport mechanisms are employed to carry the feed past the magnet and separate the magnetic products. The active separation volume for each of these separators is approximately the product of the area of the magnetised surface and the extent of the magnetic field. In order for the separators to have practical throughputs, the magnetic field must extend several centimetres. Such an extent implies a relatively low magnetic field gradient and weak magnetic forces

To overcome these disadvantages HGMS has been developed. Matrices of ferromagnetic material are used to produce much stronger but shorter range magnetic forces over large surface areas. When the matrices are placed in a magnetic field, strong magnetic forces are developed adjacent to the filaments of the matrix in approximately inverse proportion to their diameter. Since the extent of the magnetic field is approximately equal to the diameter of the filaments the magnetic fields are relatively short range. However, the magnetic field produced is intense and permits the separation and trapping of very fine, weakly magnetic particles (Oberteuffer, 1979)

magnetic separator - an overview | sciencedirect topics

The transport medium for HGMS can be either liquid or gaseous. Dry HGMS processing has the advantage of a dry product although classification of the pulverised coal is required to ensure proper separation. Small particles tend to agglomerate and pass through the separator. It has been shown that individual particles of coal in the discharge of a power plant pulveriser flow freely and hence separate well only if the material below about 10 µm is removed (Eissenberg et al., 1979). Even then drying of that part of run of mine coal to be treated by HGMS may be required to ensure good flow characteristics

A schematic representation of a batch HGMS process is shown in Figure 11.5 (Hise, 1979, 1980; Hise et al., 1979). It consists of a solenoid, the core cavity of which is filled with an expanded metal mesh. Crushed coal is fed to the top of the separator. Clean coal passes through while much of the inorganic material is trapped to be released when the solenoid is later deactivated

Data from a batch HGMS process of one size fraction of one coal are plotted in Figure 11.6 as weight per cent of material trapped in the magnetic matrix, the product sulphur and the product ash versus the independent variable of superficial transport velocity. At low superficial transport velocities the amount of material removed from the coal is high partly due to mechanical entrapment. As the velocity is increased the importance of this factor diminishes but hydrodynamic forces on the particles increase. These hydrodynamic forces oppose the magnetic force and the amount of material removed from the coal decreases (Hise, 1979)

magnetic separator - an overview | sciencedirect topics

For comparison, Figure 11.7 shows data from a specific gravity separation of the same size fraction of the same coal. While the sulphur contents of the products from the two separation processes are similar the ash content of the HGMS product is considerably higher than that of the specific gravity product. It should be emphasised that this comparison was made for one size fraction of one coal

More recently dry HGMS has been demonstrated at a scale of 1 t/h on carousel type equipment which processes coal continuously (Figure 11.8; Hise et al., 1981). A metal mesh passes continuously through the magnetised cavity so that the product coal passes through while the trapped inorganics are carried out of the field and released separately

Wet HGMS is able to treat a much wider range of coal particle sizes than dry HGMS. The efficiency of separation increases with decreasing particle size. However, depending on the end use a considerable quantity of energy may have to be expended in drying the wet, fine coal product. Wet HGMS may find particular application to the precleaning of coal for use in preparing coal water mixtures for subsequent combustion as both pulverising the coal to a fine particle size and transporting the coal in a water slurry are operations common to both processes

magnetic separator - an overview | sciencedirect topics

Work at Bruceton, PA, USA has compared the pyrite reduction potential of froth flotation followed by wet HGMS with that of a two stage froth flotation process (Hucko and Miller, 1980). Typical results are shown in Figures 11.9 and 11.10. The reduction in pyritic sulphur is similar in each case although a greater reduction in ash content is achieved by froth flotation followed by HGMS than by two stage froth flotation. However, Hucko (1979) concludes that it is highly unlikely that HGMS would be used for coal preparation independently of other beneficiation processes. As with froth flotation there is considerable variation in the amenability of various coals to magnetic beneficiation

In the magnetic separator, material is passed through the field of an electromagnet which causes the retention or retardation of the magnetic constituent. It is important that the material should be supplied as a thin sheet in order that all the particles are subjected to a field of the same intensity and so that the free movement of individual particles is not impeded. The two main types of equipment are:

Eliminators, which are used for the removal of small quantities of magnetic material from the charge to a plant. These are frequently employed, for example, for the removal of stray pieces of scrap iron from the feed to crushing equipment. A common type of eliminator is a magnetic pulley incorporated in a belt conveyor so that the non-magnetic material is discharged in the normal manner and the magnetic material adheres to the belt and falls off from the underside

magnetic separator - an overview | sciencedirect topics

Concentrators, which are used for the separation of magnetic ores from the accompanying mineral matter. These may operate with dry or wet feeds and an example of the latter is the Mastermag wet drum separator, the principle of operation of which is shown in Figure 1.43. An industrial machine is shown in operation in Figure 1.44. A slurry containing the magnetic component is fed between the rotating magnet drum cover and the casing. The stationary magnet system has several radial poles which attract the magnetic material to the drum face, and the rotating cover carries the magnetic material from one pole to another, at the same time gyrating the magnetic particles, allowing the non-magnetics to fall back into the slurry mainstream. The clean magnetic product is discharged clear of the slurry tailings. Operations can be co- or counter-current and the recovery of magnetic material can be as high as 99.5 per cent

An example of a concentrator operating on a dry feed is a rotating disc separator. The material is fed continuously in a thin layer beneath a rotating magnetic disc which picks up the magnetic material in the zone of high magnetic intensity. The captured particles are carried by the disc to the discharge chutes where they are released. The nonmagnetic material is then passed to a second magnetic separation zone where secondary separation occurs in the same way, leaving a clean non-magnetic product to emerge from the discharge end of the machine. A Mastermagnet disc separator is shown in Figure 1.45

The removal of small quantities of finely dispersed ferromagnetic materials from fine minerals, such as china clay, may be effectively carried out in a high gradient magnetic field. The suspension of mineral is passed through a matrix of ferromagnetic wires which is magnetised by the application of an external magnetic field. The removal of the weakly magnetic particles containing iron may considerably improve the “brightness” of the mineral, and thereby enhance its value as a coating or filler material for paper, or for use in the manufacture of high quality porcelain. In cases where the magnetic susceptibility of the contaminating component is too low, adsorption may first be carried out on to the surface of a material with the necessary magnetic properties. The magnetic field is generated in the gap between the poles of an electromagnet into which a loose matrix of fine stainless steel wire, usually of voidage of about 0.95, is inserted

magnetic separator - an overview | sciencedirect topics

The attractive force on a particle is proportional to its magnetic susceptibility and to the product of the field strength and its gradient, and the fine wire matrix is used to minimise the distance between adjacent magnetised surfaces. The attractive forces which bind the particles must be sufficiently strong to ensure that the particles are not removed by the hydrodynamic drag exerted by the flowing suspension. As the deposit of separated particles builds up, the capture rate progressively diminishes and, at the appropriate stage, the particles are released by reducing the magnetic field strength to zero and flushing out with water. Commercial machines usually have two reciprocating canisters, in one of which particles are being collected from a stream of suspension, and in the other released into a waste stream. The dead time during which the canisters are being exchanged may be as short as 10 s

Magnetic fields of very high intensity may be obtained by the use of superconducting magnets which operate most effectively at the temperature of liquid helium, and conservation of both gas and “cold” is therefore of paramount importance. The reciprocating canister system employed in the china clay industry is described by Svarovsky(30) and involves the use a single superconducting magnet and two canisters. At any time one is in the magnetic field while the other is withdrawn for cleaning. The whole system needs delicate magnetic balancing so that the two canisters can be moved without the use of very large forces and, for this to be the case, the amount of iron in the magnetic field must be maintained at a constant value throughout the transfer process. The superconducting magnet then remains at high field strength, thereby reducing the demand for liquid helium

Micro-organisms can play an important role in the removal of certain heavy metal ions from effluent solutions. In the case of uranyl ions which are paramagnetic, the cells which have adsorbed the ions may be concentrated using a high gradient magnetic separation process. If the ions themselves are not magnetic, it may be possible to precipitate a magnetic deposit on the surfaces of the cells. Some micro-organisms incorporate a magnetic component in their cellular structure and are capable of taking up non-magnetic pollutants and are then themselves recoverable in a magnetic field. Such organisms are referred to a being magnetotactic

magnetic separator - an overview | sciencedirect topics

where mpa→p is the inertial force and ap the acceleration of the particle. Fi are all the forces that may be present in a magnetic separator, such as the magnetic force, force of gravity, hydrodynamic drag, centrifugal force, the friction force, surface forces, magnetic dipolar forces, and electrostatic forces among the particles, and others

Workable models of particle motion in a magnetic separator and material separation must be developed separately for individual types of magnetic separators. The situation is complicated by the fact that many branches of magnetic separation, such as separation by suspended magnets, magnetic pulleys, or wet low-intensity drum magnetic separators still constitute highly empirical technology. Hesitant steps have been taken to develop theoretical models of dry separation in roll and drum magnetic separators. Alternatively, open-gradient magnetic separation, magnetic flocculation of weakly magnetic particles, and wet high-gradient magnetic separation (HGMS) have received considerable theoretical attention. A notable number of papers dealing with the problem of particle capture in HGMS led to an understanding of the interaction between a particle and a matrix element. However, completely general treatment of the magnetostatic and hydrodynamic behavior of an assembly of the material particles in a system of matrix elements, in the presence of a strong magnetic field, is a theoretical problem of considerable complexity which has not been completed, yet. Detailed description of particle behavior in various magnetic separators can be found in monographs by Gerber and Birss (1983) and Svoboda (1987, 2004)

The brick material ratio was: Slag(1.0mm<): Grog (3.0mm<): Ceramic Gravel (1.0mm<): Clay (1.0mm<) at 20 : 35 : 25 : 20. To this mixture, 2% of pigment were added. Kneading and blending was done by a Müller mixer for 15 minutes. Molding was done by a 200 ton friction press, and the bricks were loaded onto the sintering truck

magnetic separator - an overview | sciencedirect topics

This paper presents preliminary results using the Magnetic Micro-Particle Separator, (MM-PS, patent pending) which was conceived for high throughput isothermal and isobaric separation of nanometer (nm) sized iron catalyst particles from Fischer-Tropsch wax at 260 oC. Using magnetic fields up to 2,000 gauss, F-T wax with 0.3–0.5 wt% solids was produced from 25 wt% solids F-T slurries at product rates up to 230 kg/min/m2. The upper limit to the filtration rate is unknown at this time. The test flow sheet is given and preliminary results of a scale-up of 50:1 are presented

Most loads for flap valves, conveyors, vibrating feeders, crushers, paddle feeders, magnetic separators, fans and trash screens generally are supplied at 415 V three-phase 50 Hz from the 415 V Coal Plant Switchboard, although 3.3 kV supplies may be used when the duty demands. Stacker/reclaimer machines are supplied at 3.3 kV. Electrical distribution is designed to safeguard the independent operational requirements of the duplicated coal plant facilities and to ensure that an electrical fault will not result in the total loss of coal supplies to the boilers

The first step in any form of scrubbing unit is to break the lumpy materials and remove tramp elements by a magnetic separator. The product is then led into the scrubbing unit. The dry scrubbing principle is to agitate the sand grains in a stream of air so that the particles shot-blast each other. A complete dry scrubbing plant has been described in a previous book of this library in connection with sodium silicate bonded sands.* For clay-bonded sands the total AFS clay content in the reclaimed sand varies from 0·5% to 2·5% clay depending on the design of the plant

magnetic separator - an overview | sciencedirect topics

us8993342b2 - magnetic separation unit, magnetic

The disclosure relates to bio-separation devices, and in particular, to magnetic separation units and magnetic separation devices capable of separating magnetic substances in bio-samples and methods for separating the magnetic substances in the bio-samples

In the field of biology, many efficient techniques for separating one type of cell or a class of cells from a complex cell suspension are disclosed and have wide applications. The ability to remove certain cells from a clinical blood sample that are indicative of a particular disease state could be useful as a diagnostic tool for better understanding the particular state of the disease

It has been shown that cells tagged with micron sized (>1 μm) magnetic or magnetized particles can be successfully removed or separated from mixtures by using magnetic devices. For the removal of the desired cells, i.e., cells which provide valuable information, a desired cell population is magnetized and removed from a complex liquid mixture (so-called positive selection or positive separation). In an alternative method, the undesirable cells, i.e., cells that may prevent or alter the results of a particular procedure are magnetized and subsequently removed with a magnetic device (so-called negative selection or negative separation)

us8993342b2 - magnetic separation unit, magnetic

Cell separation methods utilizing magnetic tags are mainly divided into two kinds, wherein one kind is the so-called column-based separation method which uses magnetic particles with a smaller size or a weaker magnetic magnetization as tags, and separates these tags in a column filled with magnetic fillers. High magnetic gradients are generated close to the surfaces of the magnetic fillers when a magnetic field is applied to the column. The other kind is the so-called tube-based separation method using a centrifugal tube as a separation vessel. The magnetic tags are separated within a centrifugal tube by magnetic field generated by a magnet outside the tube. Therefore, larger sized tags or stronger magnetic magnetization are needed for separation efficiency. Note that for the tube-based separation method there is no need to use a column with magnetic fillers, like the column-based separation method

However, separation efficiency of the magnetic cells depends on the magnetic forces acting on the magnetic tags. Thus, an increase in the magnetic field or magnetic field gradient improves separation efficiency. However, whether using permanent magnets or electromagnets, the magnetic field and magnetic field gradient decrease as the distance increases. Therefore, separation efficiency of the magnetic cells in conventional centrifugal tubes is difficult to improve, because high magnetic filed and high magnetic field gradient cannot be applied to magnetic materials in the conventional tubes

Accordingly, a magnetic separation unit comprising a member made of a magnetic material is provided such that a high magnetic field gradient of an external magnetic field can be extended into the magnetic separation unit to improve magnetic separation efficiency. In addition, a magnetic separation device using the magnetic separation unit and a method for separating magnetic substances in a bio-sample are also provided

us8993342b2 - magnetic separation unit, magnetic

An exemplary magnetic separation unit comprises a first member made of non-magnetic materials comprising a trench extending within the first member and a second member made of magnetic materials comprising a protrusion portion protruding over a surface of the second member, wherein the first member connects to the second member such that the trench functions as a fluid channel formed between the first and second members, and the protrusion portion of the second member is contained by the trench of the first member

An exemplary magnetic separation device comprises a first magnetic field unit and the magnetic separation unit described previously. In one embodiment, the first magnetic field unit comprises a first magnetic yoke having opposite first and second surfaces and a plurality of first magnets respectively disposed over the first and second surfaces, wherein the same magnetic poles of the plurality of first magnets face the first magnetic yoke, and the magnetic separation unit described previously is disposed at one side of the first magnetic field unit, and wherein the second member of the magnetic separation unit is adjacent to the first magnetic field unit

An exemplary method for separating magnetic substances in a bio-sample comprises: providing the magnetic separation device describe previously; providing a bio-sample solution, wherein the bio-sample solution comprises magnetic bio-substances or bio-substances labeled by a magnetic target; pumping the bio-sample solution through the fluid channel in the magnetic separation device, thereby attracting or repelling the magnetic bio-substances or bio-substances labeled by a magnetic target toward a sidewall of the magnetic separation unit adjacent and parallel to the first magnetic yoke; separating the first magnetic field unit from the magnetic separation unit; and providing a buffer solution and pumping the buffer solution through the fluid channel of the magnetic separation unit, thereby eluting the magnetic bio-substances or bio-substances labeled by magnetic targets left on the sidewall of the magnetic separation unit

us8993342b2 - magnetic separation unit, magnetic

FIGS. 4 a, 4 b, 4 c, 5 a, 5 b, 5 c, 6 a, 6 b, 6 c are schematic diagrams respectively showing a cross sectional view of a first member of the magnetic separation unit shown in FIG. 3 along a line A-A′ according to various embodiments of the disclosure;

The following description is of the best-contemplated mode of carrying out the disclosure. This description is made for the purpose of illustrating the general principles of the disclosure and should not be taken in a limiting sense. The scope of the disclosure is best determined by reference to the appended claims

Magnetic separation devices according to various embodiments of the disclosure are illustrated in FIGS. 10-15 and details thereof are discussed in the following paragraphs, wherein each of the magnetic separation devices comprises at least one magnetic field unit and at least one magnetic separation unit. FIGS. 1-2 are schematic diagrams respectively showing a magnetic field unit utilized in the magnetic separation devices illustrated in FIGS. 10-15, and FIGS. 3-9 are schematic diagrams respectively showing a magnetic separation unit utilized in the magnetic separation devices illustrated in FIGS. 10-15

us8993342b2 - magnetic separation unit, magnetic

As shown in FIGS. 1-2, magnetic field units according to various embodiments of the disclosure are illustrated. FIG. 1 illustrates a perspective diagram of an exemplary magnetic field unit 100, comprising a plurality of magnets 102 and a magnetic yoke 104 respectively interposed between the magnets 102. In this embodiment, the magnets 102 are illustrated as a rectangular pillar and the magnetic yoke 104 is illustrated as a rectangular plate. As shown in FIG. 1, two of the magnets 102 in the magnetic field unit 100 are disposed on opposite surfaces of the magnetic yoke 104, and the same magnetic pole of the two magnets 102 face the magnetic yoke 104. Herein, the arrow 150 represents the interior magnetic field direction from a south pole toward a north pole of each of the magnets 102

In the magnetic field unit 100, as shown in FIG. 1, the magnets 102 and the magnetic yokes 104 are formed with similar shapes and similar surface areas, and the magnetic field unit 100 is illustrated as a rectangular pillar having a plurality of planar sidewall surfaces. Herein, the magnets 102 are formed with a surface area Am in contact with the magnetic yoke 104, and a sidewall surface 120 of each of the magnetic yokes 104 not in contact with the magnets 102 is formed with a surface area Ay. Due to the continuity of the magnetic flux lines, a magnetic flux density B at the sidewall surface 120 of the magnetic yoke 104 not in contact with the magnets 102 may be defined as follows: B=2B d A m /A y  (1),

wherein Bd represents a working magnetic flux density of the magnets 102. Bd is typically affected by factors such as the shape of the magnets and demagnetization fields, and theoretically having a value which is less than that of the remanent flux density (Br) of the magnets 102. Adequately selected Am and Ay may provide a strong magnetic field which may be greater than the remanent flux density (Br) of the magnets 102 at each of the sidewall surfaces 120 of the magnetic yoke 104 not in contact with the magnets 102, such that the magnetic field can be used in a process for separating magnetic substances in bio-samples. Herein, due to the arrangement of the plurality of magnetic yokes 104, a plurality of areas having strong magnetic fields capable of separating magnetic substances in bio-samples are provided in the magnetic field unit 100

us8993342b2 - magnetic separation unit, magnetic

FIG. 2 illustrates a perspective diagram of another exemplary magnetic field unit 100′ similar to the magnetic field unit 100 illustrated in FIG. 1. Herein, the same references represent the same components, and only differences between the magnetic field units 100 and 100′ are discussed in the following

As shown in FIG. 2, the magnetic field unit 100′ is also formed with a plurality of magnets 102 and a plurality of magnetic yokes 104 respectively disposed between the magnets 102, wherein the directions of the interior magnetic fields (represented as arrow 150) in the magnets 102 in the magnetic field unit 100′ are opposite to that of the magnets 102 located at the same places in the magnetic field unit 100 in FIG. 1. As to the arrangement shown in FIG. 2, a strong magnetic field can be thus formed near a sidewall surface 120 of each of the magnetic yokes 104 in the magnetic field unit 100′, and the magnetic field unit 100′ thus has a plurality of areas of strong magnetic fields which are greater than the remanent flux density (Br) of the magnets 102

The magnets 102 used in the magnetic field units 100 and 100′ illustrated in FIGS. 1-2 can be formed of materials such as NdFeB, SmCo, SmFeN, AlNiCo, ferrite, or combinations thereof. The magnets 102 can be formed in a configuration other than the rectangular pillar, such as circular pillar, triangular pillar or other polygonal pillar. In addition, the magnetic yokes 104 used in the magnetic field units 100 and 100′ illustrated in FIGS. 1-2 can be formed of materials such as pure iron, magnetic stainless steel or metal soft magnetic materials having predetermined permeability. The metal soft magnetic materials having predetermined permeability can be, for example, iron, silicon steel, NiFe, CoFe, stainless steel, soft magnetic ferrites, or combinations thereof. In one embodiment, the magnets 102 used in the magnetic field units 100 and 100′ can be provided with a thickness greater than 1 mm for easy application, but is not limited thereto, and the magnetic yokes 104 can be provided with a thickness of about 0.5-10 mm. In addition, for the purpose of fabricating components, a non-magnetic frame (not shown) made of materials such as stainless steel or aluminum alloys can be further provided to cover the magnetic field units 100 and 100′ shown in FIGS. 1-2 from the outside. The non-magnetic frame can be also provided with an opening or a slot at a place near each of the magnetic yokes 104 used in the magnetic field units 100 and 100′ to expose sidewall surfaces 120 of the magnetic yokes 104

us8993342b2 - magnetic separation unit, magnetic

FIG. 3 illustrates a perspective diagram of an exemplary magnetic separation unit 200, including a first member 202 made of non-magnetic materials and a second member 204 made of magnetic materials. A trench 206 is disposed at a surface of the first member 202 and the second member 204 comprises a planar portion 204 b and a plurality of protrusion portions 204 a. The trench 206 extends through the first member 202 from a top toward a bottom of the first member 202 and contains the plurality of protrusion portions 204 a toward a fluid channel in the magnetic separation unit 200 after the first member 202 and the second member 204 are combined. Thus, in the magnetic separation process, a bio-sample solution can be pumped through the fluid channel of the magnetic separation unit 200 from a top to a bottom thereof

As shown in FIG. 3, the first member 202 of the magnetic separation unit 200 is formed with a thickness W1 and the second member 204 of the magnetic separation unit 200 is formed with a thickness W2, and the trench 206 of the first member 202 is formed with a depth D. Herein, the first member 202 and the second member 204 are illustrated in a plate configuration and a width thereof can be adjusted according to a width of the corresponding magnetic field unit. In addition, locations of the first member 202 and the second member 204 shown in FIG. 3 can be exchanged and the trench 206 disposed at a surface of the first member 202 will be adjacent to the second member 204 and covered by the second member 204. Moreover, shapes and configurations of the first member 202 and the second member 204 are not limited by that shown in FIG. 3, and can be modified according corresponding configurations of the magnetic field unit 100 or 100′. In one embodiment, the second member 204 of the magnetic separation unit 200 may have a thickness W2 of about 0.02-1 mm

FIG. 4 a illustrates an exemplary cross section of the magnetic separation unit 200 taken along a line A-A′ in FIG. 3. Herein, the trench 206 of the first member 202 comprises a plurality of first sections 206 a and a plurality of second sections 206 b arranged in order, thereby forming the fluid channel passing through the first member 202 from a top toward a bottom of the first member 202. The first sections 206 a and the second sections 206 b are substantially perpendicular to each other. Herein, the first sections 206 a are illustrated as portions of the trench which are perpendicular to a shorter side of the first member 202, and the second sections 206 b are illustrated as portions of the trench 206 which are parallel to a shorter side of the first member 202, and the topmost one of the first sections 206 a may function as an input end for receiving a bio-sample solution, and the bottommost one of the first sections 206 a may function as an output end for exhausting the bio-sample solution

us8993342b2 - magnetic separation unit, magnetic

FIG. 5 a illustrates another exemplary cross section of the magnetic separation unit 200 taken along a line A-A′ in FIG. 3. Herein, the trench 206 of the first member 202 comprises a separated third section 206 c and fourth section 206 d, and a plurality of second sections 206 b is simultaneously disposed and connected between the third section 206 c and the fourth section 206 d, thereby forming the fluid channel passing through the first member 202 from a top toward a bottom thereof. The third section 206 c and the fourth section 206 d are substantially perpendicular to the second sections 206 b. Herein, the third section 206 c and the fourth section 206 d are illustrated as portions of the trench which are perpendicular to a shorter side of the first member 202, wherein the third section 206 c is disposed at a top portion of the first member 202 to function as an input end for receiving a bio-sample solution, and the fourth section 206 d is disposed at a bottom portion of the first member 202 to function as an output end for exhausting the bio-sample solution, and the second sections 206 b are illustrated as portions of the trench which are parallel to a shorter side of the first member 202

FIG. 6 a illustrates yet another exemplary cross section of the magnetic separation unit 200 taken along a line A-A′ in FIG. 3. Herein, the trench 206 of the first member 202 comprises a separated fifth section 206 e and sixth section 206 f, and a seventh section 206 g is disposed and respectively connected between the fifth section 206 e and the sixth section 206 f, thereby forming the fluid channel passing through the first member 202 from a top toward a bottom of the first member 202. The fifth section 206 e and the sixth section 206 f are illustrated as portions of the trench 206 which are perpendicular to a shorter side of the first member 202, and the fifth section 206 e is disposed at a top portion of the first member to function as an input end for receiving a bio-sample solution, and the sixth section 206 f is disposed at a bottom portion of the first member 202 to function as an output end for exhausting the bio-sample solution, and the seventh section 206 g is illustrated as an inner chamber disposed in the first member 202

In the embodiments shown in FIGS. 4 a, 5 a, and 6 a, the first section 206 a, the third section 206 c, the fourth section 206 d, the fifth section 206 e and the sixth section 206 f in each first member 202 are illustrated as a portion of the trench which is perpendicular to a shorter side of the first member 202, and the first section 206 a, the third section 206 c and the fifth section 206 e in the top portion of the first member 202 may function as an input end, and the first section 206 a, the fourth section 206 d and the sixth section 206 f in the bottom portion of the first member 202 may function as an output end, but are not limited thereto. In other embodiments, a portion of the first section 206 a, the third section 206 c, the fourth section 206 d, the fifth section 206 e and the sixth section 206 f can be disposed at a portion of the longer side of the first member 202. As shown in FIG. 4 b, a portion of the topmost first section 206 a turns toward a longer side of the first member 202, and as shown in FIGS. 5 b and 6 b, a portion of the third section 206 c and a portion of the fifth section 206 e may turn toward a longer side of the first member 202. In addition, as shown in FIGS. 4 c, 5 c and 6 c, a portion of the bottommost first section 206 a, a portion of the fourth section 206 d, and a portion of the sixth section 206 f may respectively turn towards a longer side of the first member 202. Thus, the portions of the sections functioning as input and output ends may face to either a longer side or a shorter side of the first member 202

us8993342b2 - magnetic separation unit, magnetic

FIG. 7 is an exploded diagram showing the magnetic separation unit 200, as shown in FIG. 3. Herein, the second member 204 mainly comprises a planar portion 204 b and a plurality of protrusion portions 204 a, and the protrusion portions 204 a are formed over a surface of the planar portion 204 b and are opposite to the second sections 206 b (see FIGS. 4-5) and the seventh section 206 g (see FIG. 6) of the first member 202 and can be contained by the second sections 206 b and the seventh section 206 g of the first member 202. Numbers and locations of the protrusion portions 204 a can be properly adjusted according to the configuration of the first member 202 shown in FIGS. 4-6 and is not limited by that illustrated in FIG. 7

FIG. 8 illustrates a cross sectional view of a region 900 as shown in FIG. 3. As shown in FIG. 8, after combination of the first member 202 and the second member 204, a fluid channel is defined by the trench 206 in the first member 202 and the protrusion 204 a of the second member 204 is contained by a portion of the fluid channel but not entirely. Due to formation of the second member 204 and the protrusion portions 204 a formed thereover, an external magnetic field can be guided to the fluid channel in the magnetic separation unit to enhance the strength of the magnetic field applied to the fluid channel and to increase magnetic separation efficiency

In FIG. 9, another embodiment similar to that shown in FIG. 8 is illustrated. As shown in FIG. 9, another surface opposite to where the protrusion portions 204 a are formed is correspondingly formed with a recess portion 204 c such that an external magnetic field can be further guided to the fluid channel in the magnetic separation unit to enhance the strength of the magnetic field applied to the fluid channel and to increase magnetic separation efficiency

us8993342b2 - magnetic separation unit, magnetic

As shown in FIGS. 8-9, the protrusion portions 204 a and the recess portions 204 c are illustrated as successive triangle-shaped protrusions but are not limited thereto. The portions can be successive protrusions with other shapes such as rectangular, trapezoid or curve shapes

In the magnetic separation unit shown in FIGS. 3-9, the first member 202 is made of non-magnetic materials such as plastic, bakelite, non-magnetic metal or ceramic and is not limited thereto, and the trench 206 can be formed therein by suitable processing methods. The second member 204 is made of magnetic materials such as pure iron, magnetic stainless steel, metal soft magnetic materials of predetermined permeability, or soft magnetic ferrites. The metal soft magnetic materials of predetermined permeability can be, for example, iron, silicon steel, NiFe, CoFe, stainless steel, soft magnetic ferrites, or combinations thereof

FIGS. 10-15 illustrate magnetic separation devices according to various embodiments of the disclosure, wherein each of the magnetic separation devices may incorporate the magnetic field units and the magnetic separation units described and illustrated previously

us8993342b2 - magnetic separation unit, magnetic

FIG. 10 illustrates an exemplary magnetic separation device 300 comprising the magnetic field unit 100, as shown in FIG. 1 and the magnetic separation unit 200, as shown in FIG. 3. Herein, the magnetic separation unit 200 is disposed at a side of the magnetic field unit 100 by methods such as hooking or adhering, and the second member 204 in the magnetic separation unit 200 is preferably adjacent to the magnetic field unit 100, and a portion of the second sections 206 b shown in FIGS. 4-5 or the seventh section 206 g shown in FIG. 6 is parallel to a side of each of the magnetic yokes 104 in the magnetic field unit 100. In such a configuration as shown in FIG. 10, magnetic flux lines (not shown) of two magnets adjacent to one of the magnetic yokes 104 in the magnetic field unit 100 are gathered to the magnetic yoke 104 interposed therebetween, and the magnetic flux lines are further guided to the second sections 206 b (see FIGS. 4-5) or the seventh section 206 g (see FIG. 6) of the trench 206 in the magnetic separation unit 200 adjacent and parallel to the magnetic yoke 104 by the protrusion portions 204 a of the second member 204 of the separation unit 200, thereby making the second sections 206 b shown in FIGS. 4-5 or the seventh section 206 g shown in FIG. 6 of the trench 206 of the magnetic separation unit 200 as the main separation portions in the magnetic separation device 300 for separating magnetic substances in a bio-sample solution. In one embodiment, the main separation sections have a depth D of about 0.1-2 mm

FIG. 11 illustrates another exemplary magnetic separation device 300′ similar to the magnetic separation device 300 illustrated in FIG. 10. Herein, the same references represent the same components, and only differences therebetween are discussed in the following paragraphs

As shown in FIG. 11, the magnetic separation device 300′ comprises a magnetic field unit 100, as shown in FIG. 1 and two magnetic separation units 200, as shown in FIG. 3. The magnetic separation units 200 are disposed on opposite sides of the magnetic field unit 100, respectively, and the second member 204 of each of the magnetic separation units 200 is preferably adjacent to the magnetic field unit 100. Through such a configuration, as shown in FIG. 11, the magnetic separation device 300′ may provide a magnetic separation process for simultaneously separating more than one set of solutions of bio-samples, thereby improving throughput and efficiencies of the magnetic separation process

us8993342b2 - magnetic separation unit, magnetic

In other embodiments, configurations of the magnetic separation unit 200 in the magnetic separation device are not limited to those illustrated in FIGS. 10-11. A magnetic separation unit may be provided at each side of the magnetic field unit, or the magnetic separations units 200 can be located at adjacent sides of the magnetic field unit to improve throughput and efficiencies of the magnetic separation process

FIG. 12 illustrates another exemplary magnetic separation device 400, comprising two magnetic field units 100, as shown in FIG. 1 and a magnetic separation unit 200, as shown in FIG. 3. Herein the magnetic separation unit 200 is interposed between the magnetic field units 100, and the magnetic separation unit 200 can be disposed at a side of each of the magnetic field units 100 by methods such as hooking or adhering, and the second member 204 in the magnetic separation units 200 is adjacent to one of the magnetic field units 100, and portions of the second sections 206 b shown in FIGS. 4-5 or the seventh section 206 g shown in FIG. 6 of the trench 206, adjacent and parallel to a side of each of the magnetic yokes 104 in the magnetic field unit 100. For such a configuration, as shown in FIG. 12, magnetic flux lines (not shown) of two magnets adjacent to one of the magnetic yokes 104 in the magnetic field unit 100 are gathered to the magnetic yoke 104 interposed therebetween, and the magnetic flux lines are further guided to the second sections 206 b (see FIGS. 4-5) or the seventh section 206 g (see FIG. 6) of the trench 206 in the magnetic separation unit 200 adjacent and parallel to the magnetic yoke 104 by the protrusion portions 204 a of the second member 204 of the separation unit 200, thereby making the second sections 206 b shown in FIGS. 4-5 or the seventh section 206 g shown in FIG. 6 of the trench 206 of the magnetic separation unit 200 as main separation portions in the magnetic separation device 400 for separating magnetic substances in a bio-sample solution. In addition, more than one set of the magnetic field units can be disposed in the magnetic separation device 400 to further improve magnetic field strength such that the efficiency of magnetic separation can be improved

In other embodiments, the numbers and configurations of the magnetic separation units 200 and the magnetic field units 100 disposed in the magnetic separation device are not limited to those illustrated in FIG. 12. As shown in FIG. 13, a magnetic separation unit can be respectively interposed between a number of n (n is an integer greater than 2 and n=3 in this embodiment) magnetic field units such that the magnetic separation device provides a magnetic separation device 400′ comprising n magnetic field units and n−1 magnetic separation units. FIG. 14 illustrates another exemplary magnetic separation device 500 formed by replacing one of the magnetic field units 100 therein with the magnetic field unit 100′ shown in FIG. 2. FIG. 15 illustrates an exemplary magnetic separation device 500′ formed by replacing one of the n magnetic field units 100 with the magnetic field unit 100′ illustrated in FIG. 2. The previously illustrated configurations of the magnetic separation device are good for improving efficiency of the magnetic separation process provided thereby. In the embodiments shown in FIGS. 14-15, the second member 204 of each magnetic separation unit 200 is preferably adjacent to the magnetic field unit 100 and 100′, and the second member 204 of each magnetic separation unit 200 disposed between the magnetic field unit 100 and 100′ is adjacent to the magnetic field unit 100 or 100′

us8993342b2 - magnetic separation unit, magnetic

First, in step S801, a magnetic separation device such as one of the magnetic separation devices illustrated in FIGS. 10-15 is provided. Next, in step S803, a bio-sample solution comprising magnetic substances is provided. The magnetic substances can be magnetic bio-substances or bio-substances labeled with magnetic targets. Next, in step 805, the bio-sample solution is then pumped through the fluid channel in the magnetic separation device and the magnetic substances therein are attracted or repelled toward the interior sidewalls of the fluid channel, such as toward the interior sidewalls of the second section or the seventh section near the magnetic yoke and portions of the interior sidewalls adjacent to the magnetic yoke. Next, in step S807, the magnetic field unit and the magnetic separation unit in the magnetic separation device are separated by individually removing the magnetic separation unit or the magnetic field unit. In one embodiment, the magnetic separation unit is removed from the magnetic separation device. Finally, in step S809, a buffer solution is provided and then flowed through the fluid channel of the magnetic separation device to elute the magnetic substances left on the interior sidewalls of the second section or the seventh section of the fluid channel and other sections adjacent thereto

In one embodiment, the solution of the bio-sample may flow through magnetic separation device and may comprise magnetic substances or bio-substances labeled by magnetic targets. The bio-sample can be, for example, blood samples, condensed blood samples, tissue samples, tissue solution samples, cell samples, cell culture samples, microorganism samples, protein samples, amino acid samples, and nucleic acid samples. The magnetic substances can be, for example, metal particles such as Fe, Co, Ni, or oxide particles thereof. The buffer solution can be, for example, Tris-buffer saline (TBS), phosphate buffer saline (PBS), normal saline, and solutions having the same tension as a culture solution and other solutions capable of maintaining activities of proteins, amino acids or nucleic acids

A magnetic separation device as illustrated in FIG. 10 was provided, comprising magnets 102 made of NdFeB and an overall size (length×width×height) of 40 mm×40 mm×40 mm. The magnetic yokes 104 were made of pure iron and was formed with an overall rectangular size (length×width) of 40 mm×40 mm and a thickness of about 2.4 mm. The first member 202 in the magnetic separation unit 200 has a trench 206 with an overall size (length×width×height) of 25 mm×145 mm×200 μm formed by processing acrylic materials and the inlet and outlet for the sample flow in and out were formed in the first member 202 by drilling. The second member 204 in the magnetic separation unit 200 was made of permalloy and has a thickness of about 0.1 mm, having protrusions 204 a of a protrusion dimension of about 0.1 mm, wherein the protrusion 204 a of the second member 204 was disposed depending on the strong magnetic regions in the magnetic separation unit. A bio-sample was pumped through the fluid channel in the magnetic separation unit, wherein the bio-sample was a solution comprising Fe3O4 particles with a size of 30 nm-1000 nm therein. The Fe contents in the solutions before and after separation were measured. Table 1 shows the measurement results and separation efficiency of the bio-sample 1 was 94.9%

us8993342b2 - magnetic separation unit, magnetic

Separation efficiency tests were performed by using the magnetic separation device disclosed in example 1. The test samples were commercial BD IMag magnetic particles with particle sizes of about 100-450 nm. A wash solution was collected when the test sample flowed through the magnetic separation device. Then the magnetic separation unit was removed, and the elution was collected when a buffer solution is pumped through the fluid channel. Fe contents in the wash and elution was measured. Table 2 shows the measurement results and separation efficiency of the bio-sample 2 was 98.4%

While the disclosure has been described by way of examples and in terms of several embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements

magnetic separator- an overview | sciencedirect topics

As magnetic separators progress toward larger capacity, higher efficiency, and lower operating costs, some subeconomic iron ores have been utilized in recent years. For example, magnetite iron ore containing only about 4% Fe (beach sands or ancient beach sands) to 15% Fe (iron ore formations) and oxidized iron ore of only about 10% Fe (previously mine waste) to 20% Fe (oxidized iron ore formations) are reported to be utilized. They are first crushed and the coarse particles pretreated using roll magnetic separators. The magnetic product of roll magnetic separators may reach 25–40% Fe and then is fed to mineral processing plants

As shown in Figure 5, slurry is fed from the top of an inclined screen in a low-intensity magnetic field, with the mesh size of screen sufficiently larger than those of particles in slurry. As the slurry flows down the above surface of screen, magnetic particles agglomerate with the size of agglomerations increasingly growing and roll down as magnetic concentrate at the lower end of screen. The less- or nonmagnetic particles pass through the screen as tailings. Figure 5 shows the operation of screen magnetic separators for cleaning of magnetite

Commercial magnetic separators are continuous-process machines, and separation is carried out on a moving stream of particles passing into and through the magnetic field. Close control of the speed of passage of the particles through the field is essential, which typically rules out free fall as a means of feeding. Belts or drums are very often used to transport the feed through the field

As discussed in Section 13.4.1, flocculation of magnetic particles is a concern in magnetic separators, especially with dry separators processing fine material. If the ore can be fed through the field in a monolayer, this effect is much less serious, but, of course, the capacity of the machine is drastically reduced. Flocculation is often minimized by passing the material through consecutive magnetic fields, which are usually arranged with successive reversals of the polarity. This causes the particles to turn through 180°, each reversal tending to free the entrained gangue particles. The main disadvantage of this method is that flux tends to leak from pole to pole, reducing the effective field intensity

magnetic separator- an overview | sciencedirect topics

Provision for collection of the magnetic and nonmagnetic fractions must be incorporated into the design of the separator. Rather than allow the magnetics to contact the pole-pieces, which then requires their detachment, most separators are designed so that the magnetics are attracted to the pole-pieces, but come into contact with some form of conveying device, which carries them out of the influence of the field, into a bin or a belt. Nonmagnetic disposal presents no problems; free fall from a conveyor into a bin is often used. Middlings are readily produced by using a more intense field after the removal of the highly magnetic fraction

Conventional magnetic separators are largely confined to the separation or filtration of relatively large particles of strongly magnetic materials. They employ a single surface for separation or collection of magnetic particles. A variety of transport mechanisms are employed to carry the feed past the magnet and separate the magnetic products. The active separation volume for each of these separators is approximately the product of the area of the magnetised surface and the extent of the magnetic field. In order for the separators to have practical throughputs, the magnetic field must extend several centimetres. Such an extent implies a relatively low magnetic field gradient and weak magnetic forces

To overcome these disadvantages HGMS has been developed. Matrices of ferromagnetic material are used to produce much stronger but shorter range magnetic forces over large surface areas. When the matrices are placed in a magnetic field, strong magnetic forces are developed adjacent to the filaments of the matrix in approximately inverse proportion to their diameter. Since the extent of the magnetic field is approximately equal to the diameter of the filaments the magnetic fields are relatively short range. However, the magnetic field produced is intense and permits the separation and trapping of very fine, weakly magnetic particles (Oberteuffer, 1979)

magnetic separator- an overview | sciencedirect topics

The transport medium for HGMS can be either liquid or gaseous. Dry HGMS processing has the advantage of a dry product although classification of the pulverised coal is required to ensure proper separation. Small particles tend to agglomerate and pass through the separator. It has been shown that individual particles of coal in the discharge of a power plant pulveriser flow freely and hence separate well only if the material below about 10 µm is removed (Eissenberg et al., 1979). Even then drying of that part of run of mine coal to be treated by HGMS may be required to ensure good flow characteristics

A schematic representation of a batch HGMS process is shown in Figure 11.5 (Hise, 1979, 1980; Hise et al., 1979). It consists of a solenoid, the core cavity of which is filled with an expanded metal mesh. Crushed coal is fed to the top of the separator. Clean coal passes through while much of the inorganic material is trapped to be released when the solenoid is later deactivated

Data from a batch HGMS process of one size fraction of one coal are plotted in Figure 11.6 as weight per cent of material trapped in the magnetic matrix, the product sulphur and the product ash versus the independent variable of superficial transport velocity. At low superficial transport velocities the amount of material removed from the coal is high partly due to mechanical entrapment. As the velocity is increased the importance of this factor diminishes but hydrodynamic forces on the particles increase. These hydrodynamic forces oppose the magnetic force and the amount of material removed from the coal decreases (Hise, 1979)

magnetic separator- an overview | sciencedirect topics

For comparison, Figure 11.7 shows data from a specific gravity separation of the same size fraction of the same coal. While the sulphur contents of the products from the two separation processes are similar the ash content of the HGMS product is considerably higher than that of the specific gravity product. It should be emphasised that this comparison was made for one size fraction of one coal

More recently dry HGMS has been demonstrated at a scale of 1 t/h on carousel type equipment which processes coal continuously (Figure 11.8; Hise et al., 1981). A metal mesh passes continuously through the magnetised cavity so that the product coal passes through while the trapped inorganics are carried out of the field and released separately

Wet HGMS is able to treat a much wider range of coal particle sizes than dry HGMS. The efficiency of separation increases with decreasing particle size. However, depending on the end use a considerable quantity of energy may have to be expended in drying the wet, fine coal product. Wet HGMS may find particular application to the precleaning of coal for use in preparing coal water mixtures for subsequent combustion as both pulverising the coal to a fine particle size and transporting the coal in a water slurry are operations common to both processes

magnetic separator- an overview | sciencedirect topics

Work at Bruceton, PA, USA has compared the pyrite reduction potential of froth flotation followed by wet HGMS with that of a two stage froth flotation process (Hucko and Miller, 1980). Typical results are shown in Figures 11.9 and 11.10. The reduction in pyritic sulphur is similar in each case although a greater reduction in ash content is achieved by froth flotation followed by HGMS than by two stage froth flotation. However, Hucko (1979) concludes that it is highly unlikely that HGMS would be used for coal preparation independently of other beneficiation processes. As with froth flotation there is considerable variation in the amenability of various coals to magnetic beneficiation

In the magnetic separator, material is passed through the field of an electromagnet which causes the retention or retardation of the magnetic constituent. It is important that the material should be supplied as a thin sheet in order that all the particles are subjected to a field of the same intensity and so that the free movement of individual particles is not impeded. The two main types of equipment are:

Eliminators, which are used for the removal of small quantities of magnetic material from the charge to a plant. These are frequently employed, for example, for the removal of stray pieces of scrap iron from the feed to crushing equipment. A common type of eliminator is a magnetic pulley incorporated in a belt conveyor so that the non-magnetic material is discharged in the normal manner and the magnetic material adheres to the belt and falls off from the underside

magnetic separator- an overview | sciencedirect topics

Concentrators, which are used for the separation of magnetic ores from the accompanying mineral matter. These may operate with dry or wet feeds and an example of the latter is the Mastermag wet drum separator, the principle of operation of which is shown in Figure 1.43. An industrial machine is shown in operation in Figure 1.44. A slurry containing the magnetic component is fed between the rotating magnet drum cover and the casing. The stationary magnet system has several radial poles which attract the magnetic material to the drum face, and the rotating cover carries the magnetic material from one pole to another, at the same time gyrating the magnetic particles, allowing the non-magnetics to fall back into the slurry mainstream. The clean magnetic product is discharged clear of the slurry tailings. Operations can be co- or counter-current and the recovery of magnetic material can be as high as 99.5 per cent

An example of a concentrator operating on a dry feed is a rotating disc separator. The material is fed continuously in a thin layer beneath a rotating magnetic disc which picks up the magnetic material in the zone of high magnetic intensity. The captured particles are carried by the disc to the discharge chutes where they are released. The nonmagnetic material is then passed to a second magnetic separation zone where secondary separation occurs in the same way, leaving a clean non-magnetic product to emerge from the discharge end of the machine. A Mastermagnet disc separator is shown in Figure 1.45

The removal of small quantities of finely dispersed ferromagnetic materials from fine minerals, such as china clay, may be effectively carried out in a high gradient magnetic field. The suspension of mineral is passed through a matrix of ferromagnetic wires which is magnetised by the application of an external magnetic field. The removal of the weakly magnetic particles containing iron may considerably improve the “brightness” of the mineral, and thereby enhance its value as a coating or filler material for paper, or for use in the manufacture of high quality porcelain. In cases where the magnetic susceptibility of the contaminating component is too low, adsorption may first be carried out on to the surface of a material with the necessary magnetic properties. The magnetic field is generated in the gap between the poles of an electromagnet into which a loose matrix of fine stainless steel wire, usually of voidage of about 0.95, is inserted

magnetic separator- an overview | sciencedirect topics

The attractive force on a particle is proportional to its magnetic susceptibility and to the product of the field strength and its gradient, and the fine wire matrix is used to minimise the distance between adjacent magnetised surfaces. The attractive forces which bind the particles must be sufficiently strong to ensure that the particles are not removed by the hydrodynamic drag exerted by the flowing suspension. As the deposit of separated particles builds up, the capture rate progressively diminishes and, at the appropriate stage, the particles are released by reducing the magnetic field strength to zero and flushing out with water. Commercial machines usually have two reciprocating canisters, in one of which particles are being collected from a stream of suspension, and in the other released into a waste stream. The dead time during which the canisters are being exchanged may be as short as 10 s

Magnetic fields of very high intensity may be obtained by the use of superconducting magnets which operate most effectively at the temperature of liquid helium, and conservation of both gas and “cold” is therefore of paramount importance. The reciprocating canister system employed in the china clay industry is described by Svarovsky(30) and involves the use a single superconducting magnet and two canisters. At any time one is in the magnetic field while the other is withdrawn for cleaning. The whole system needs delicate magnetic balancing so that the two canisters can be moved without the use of very large forces and, for this to be the case, the amount of iron in the magnetic field must be maintained at a constant value throughout the transfer process. The superconducting magnet then remains at high field strength, thereby reducing the demand for liquid helium

Micro-organisms can play an important role in the removal of certain heavy metal ions from effluent solutions. In the case of uranyl ions which are paramagnetic, the cells which have adsorbed the ions may be concentrated using a high gradient magnetic separation process. If the ions themselves are not magnetic, it may be possible to precipitate a magnetic deposit on the surfaces of the cells. Some micro-organisms incorporate a magnetic component in their cellular structure and are capable of taking up non-magnetic pollutants and are then themselves recoverable in a magnetic field. Such organisms are referred to a being magnetotactic

magnetic separator- an overview | sciencedirect topics

where mpa→p is the inertial force and ap the acceleration of the particle. Fi are all the forces that may be present in a magnetic separator, such as the magnetic force, force of gravity, hydrodynamic drag, centrifugal force, the friction force, surface forces, magnetic dipolar forces, and electrostatic forces among the particles, and others

Workable models of particle motion in a magnetic separator and material separation must be developed separately for individual types of magnetic separators. The situation is complicated by the fact that many branches of magnetic separation, such as separation by suspended magnets, magnetic pulleys, or wet low-intensity drum magnetic separators still constitute highly empirical technology. Hesitant steps have been taken to develop theoretical models of dry separation in roll and drum magnetic separators. Alternatively, open-gradient magnetic separation, magnetic flocculation of weakly magnetic particles, and wet high-gradient magnetic separation (HGMS) have received considerable theoretical attention. A notable number of papers dealing with the problem of particle capture in HGMS led to an understanding of the interaction between a particle and a matrix element. However, completely general treatment of the magnetostatic and hydrodynamic behavior of an assembly of the material particles in a system of matrix elements, in the presence of a strong magnetic field, is a theoretical problem of considerable complexity which has not been completed, yet. Detailed description of particle behavior in various magnetic separators can be found in monographs by Gerber and Birss (1983) and Svoboda (1987, 2004)

The brick material ratio was: Slag(1.0mm<): Grog (3.0mm<): Ceramic Gravel (1.0mm<): Clay (1.0mm<) at 20 : 35 : 25 : 20. To this mixture, 2% of pigment were added. Kneading and blending was done by a Müller mixer for 15 minutes. Molding was done by a 200 ton friction press, and the bricks were loaded onto the sintering truck

magnetic separator- an overview | sciencedirect topics

This paper presents preliminary results using the Magnetic Micro-Particle Separator, (MM-PS, patent pending) which was conceived for high throughput isothermal and isobaric separation of nanometer (nm) sized iron catalyst particles from Fischer-Tropsch wax at 260 oC. Using magnetic fields up to 2,000 gauss, F-T wax with 0.3–0.5 wt% solids was produced from 25 wt% solids F-T slurries at product rates up to 230 kg/min/m2. The upper limit to the filtration rate is unknown at this time. The test flow sheet is given and preliminary results of a scale-up of 50:1 are presented

Most loads for flap valves, conveyors, vibrating feeders, crushers, paddle feeders, magnetic separators, fans and trash screens generally are supplied at 415 V three-phase 50 Hz from the 415 V Coal Plant Switchboard, although 3.3 kV supplies may be used when the duty demands. Stacker/reclaimer machines are supplied at 3.3 kV. Electrical distribution is designed to safeguard the independent operational requirements of the duplicated coal plant facilities and to ensure that an electrical fault will not result in the total loss of coal supplies to the boilers

The first step in any form of scrubbing unit is to break the lumpy materials and remove tramp elements by a magnetic separator. The product is then led into the scrubbing unit. The dry scrubbing principle is to agitate the sand grains in a stream of air so that the particles shot-blast each other. A complete dry scrubbing plant has been described in a previous book of this library in connection with sodium silicate bonded sands.* For clay-bonded sands the total AFS clay content in the reclaimed sand varies from 0·5% to 2·5% clay depending on the design of the plant

magnetic separator- an overview | sciencedirect topics

magnetic separation: magnetic sorting technology with

Magnetic and non-ferrous metal separators from STEINERT perfectly satisfy efficiency requirements for the accurate separation of primary and secondary raw materials. Tried-and-tested machines are available for diverse applications ranging from sorting scrap material and waste to mining applications. We offer a large selection of pulley, drum, lift-out and overhead suspension magnets – for both dry and wet processing

If a tight installation space requires a compact machine, then our combination separators with several magnetic sorting stages are the ideal solution. For example, the STEINERT FinesMaster directly combines two serial magnetic separators with one eddy current separator, producing an incredibly efficient and compact machine solution

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