Device and method for performing magnetic separation

Abstract

A magnetic separator includes a transfer system configured to drive a transfer element in a running direction, and a cooperating magnetic assembly disposed proximate to the transfer element. The magnetic assembly includes a magnetic body having rows of magnets oriented transversely with respect to a longitudinal axis of the magnetic assembly, the longitudinal axis being arranged substantially parallel to a running direction of the conveying element. The pole axis of each magnet is arranged substantially parallel to the longitudinal axis, and successive rows of magnets are arranged such that the same poles of the magnets face and repel each other to establish a region having alternating magnetic polarities. Elongated bulkheads may be sandwiched between successive rows of magnets. A method of separating magnetically sensitive particles from a mixture using the separator is also provided. The mixture may comprise, for example, raw ore, crushed ore, mining waste, or slag.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of South African Patent Application No. 2022 / 13909, filed on December 22, 2022, which is incorporated herein by reference. Technical field

[0003] The present invention relates to the separation of magnetically sensitive particles from mine tailings, run - of - the - mine (ROM), crushed ore, paste, and other types of mixtures. Background art

[0004] Mining is an important industry globally. An important aspect of mining is the separation of valuable materials from valueless materials. Separation may be required before and after processing the raw ("virgin") materials during mining. For example, separation techniques can be applied to separate the components of ROM, crushed ore, or mining waste. This includes the separation of pre - processed materials and post - processed materials. ROM is unprocessed mining material or ore in its natural state, consisting of overburden soil and rock, minerals, intermediate products, contaminants, and impurities. Mining waste is typically produced as a by - product of mining operations. Mining waste refers to the materials extracted and processed from the ground during the ore processing and enrichment stages of the mining process, which remain after the valuable materials have been extracted. Mining waste has low to no economic value and is considered unusable mineralized material. The effective separation of valuable materials from valueless materials is a problem faced in all stages of the mining process.

[0005] Mining waste products and crushed ore or ROM can include combinations of fine suspended materials, including potentially valuable dissolved metals. Mining waste products can also include reagents, chemicals, and inorganic and organic additives. Such mining waste itself can exist in the form of waste rock or process waste, aqueous solutions, particulate emissions, water treatment sludge, metallurgical slag, etc. Mining waste in the form of waste rock typically does not contain economically interesting metal concentrations because the significant investment in extracting and separating such valuable metals from the surrounding waste products is not cost - effective.

[0006] Mining waste is often stored near the mining production site because transporting it to another location may be economically unfeasible. Mining waste is usually stored in the form of a slurry in large artificial embankments commonly known as tailings dams. Other mining waste or materials that are easy to reprocess or further process through the mining process include crushed ore, ROM, and paste. Tailings are the waste left after extracting the target mineral or metal from the ore and consist of gravel, water, trace amounts of the target metal, and additives used for processing. There are different types of tailings, and they can be produced, for example, by the processing of iron ore, copper, manganese, chromite ore, mineral sands, platinum group metals (PGM), ferrochrome, tin ore, cobalt, nickel, etc.

[0007] Since the product extraction process in mining operations is never completely efficient, the accumulation of tailings at the mine is becoming an increasing environmental problem.

[0008] Current technologies and physical separation methods used in the mining industry to process and separate valuable materials from mixtures of raw materials or mining waste include flotation, gravity separation, centrifugal separation, magnetic separation, density separation (such as countercurrent classifiers), shaking tables, and various other techniques. Separation is used to remove valuable components from the gangue (the commercially valueless material in which the ore is found) in the slurry or to remove impurities (contaminants) from the desired material. The choice of a particular separation technique is based on the properties or quality of the material to be extracted, such as weight, magnetism, density, etc. Combinations of these techniques can also be used to first separate the metal or mineral from the waste and second to separate the components of the recovered material from each other. The result of insufficient separation and refining during the processing stage is the accumulation of mining waste.

[0009] The waste recycling or reuse process for reprocessing mining waste includes separation methods and techniques similar to those described above. These reprocessing or additional processing methods and techniques face similar technical and economic challenges as those faced in the original extraction and separation processing steps. An inherent disadvantage of gravity separation is the significant loss of tailings that occurs when the method is of the density type. An inherent disadvantage of existing methods and systems for magnetic separation is that some metals require high magnetic fluxes for separation, especially when separating paramagnetic minerals. Most magnetic separators achieve a maximum magnetic flux field of approximately 1.5 Tesla (15,000 Gauss) on a direct magnetic surface, where only approximately 1.1 Tesla (11,000 Gauss) acts on magnetic or paramagnetic particles in motion. This weak adsorption potential results in a low recovery rate of valuable materials and leaves a relatively large amount of valuable materials in the mixture after separation. Therefore, existing methods and systems for magnetic separation exhibit low economic feasibility because the cost of incorporating sufficiently strong magnets or electromagnets is too high. Existing methods and systems also do not provide an adjustment of the magnetic flux field according to the materials the system is designed to adsorb, and although the system is applied to variable materials and metals, it typically provides a constant magnetic flux field, i.e., existing methods and systems are not target-specific. Another disadvantage of existing methods and systems is that magnetically sensitive particles are not easily agitated and loosened from the flowing pulp as it passes through the separator, making it more difficult for the particles to be separated from the surrounding gangue in the pulp.

[0010] Therefore, current methods for processing, reprocessing, separating, and extracting precious metals, paramagnetic materials, and other magnetically sensitive valuable substances (value) from gangue in pulp, tailings, crushed ore, ROM, and paste may not be sufficient to extract an economically viable amount of such desired materials.

[0011] The foregoing discussion of the background of the invention is only intended to facilitate an understanding of the invention. It should be considered that this discussion is not an indication or admission that any of the materials mentioned were part of the common general knowledge in the art prior to the priority date of the present application. Summary of the Invention

[0012] According to one aspect of the present invention, there is provided a magnetic separator comprising a conveyor system configured to drive a conveyor element in a running direction, and a cooperating magnetic assembly disposed adjacent to the conveyor element;

[0013] The magnetic assembly has a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveyor element; and

[0014] The magnetic assembly includes at least one magnetic body having an array of magnets;

[0015] Wherein, the rows of magnets in the array are oriented transversely with respect to the longitudinal axis of the magnetic assembly, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions of alternating magnetic polarity along the magnetic body.

[0016] The conveying system may include a belt conveying system, and the conveying element may include a conveyor belt. The cooperating magnetic assembly may include a conveyor bed. The conveyor bed may be arranged to support the conveyor belt.

[0017] In certain embodiments, the present invention may provide a magnetic separator comprising:

[0018] A belt conveying system configured to drive a conveyor belt in a running direction; and

[0019] A conveyor bed arranged to support the conveyor belt, the conveyor bed having a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveyor belt;

[0020] The conveyor bed includes at least one magnetic body having an array of magnets;

[0021] Wherein, the rows of magnets in the array are oriented transversely with respect to the longitudinal axis of the conveyor bed, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions of alternating magnetic polarity along the magnetic body.

[0022] The magnetic body may further include at least one elongated separator disposed or sandwiched between consecutive rows of repulsive magnets in the array. The separator may be oriented transversely with respect to the longitudinal axis of the conveyor bed. The magnetic body may include a plurality of such separators arranged substantially parallel to each other. The separators may be arranged in a regular spaced sequence along the length of the magnetic body, wherein each plate extends across the width of the magnetic body. The separator may also be referred to as an accelerator plate or fin.

[0023] Each separator may abut two rows of magnets, with the separator disposed between the two rows of magnets. In certain non-limiting embodiments, the separator may have a thickness in the range of about 1 mm to about 30 mm, optionally about 2 mm to about 4 mm, optionally about 2.5 mm to about 3 mm.

[0024] The conveyor bed may further include a back plate. The back plate may be positioned on one side of the conveyor bed, opposite the portion of the conveyor belt configured to feed a mixture of particulate material, such that the magnetic body separates the back plate from the conveyor belt. The back plate may be adjacent to the magnetic body. The thickness of the back plate may be in the range of about 20 mm to about 50 mm, optionally about 30 mm. The back plate may be substantially non-magnetic. Without limitation, the back plate may be made of stainless steel. The back plate may be made of a composite non-magnetic material.

[0025] The magnetic separator may include a washing device for washing the pulp or other feed mixture conveyed on the conveyor belt during operation.

[0026] The magnetic separator may further include a feeding device for feeding the pulp or other feed mixture onto the conveyor belt in the mixture loading area. The feeding device may be configured to be adjustable. The feeding device may be configured to be set at an adjustable distance from the conveyor belt.

[0027] The magnetic separator may further include a material removal device for removing magnetically sensitive and paramagnetic particles from the conveyor belt in the particle recovery area. The material removal device may include one or more scrapers. The material removal device may include at least one water spray bar combined with one or more scrapers.

[0028] Generally, the running direction of the conveyor belt is towards the particle recovery area. The particles adsorbed by the magnet may be carried towards the recovery area in the sludge adhering to the conveyor belt, where they may be removed from the conveyor belt by the material removal device.

[0029] The belt conveyor system may be configured such that the conveyor bed and the conveyor belt have an operably inclined orientation. The inclination may be adjustable.

[0030] The magnetically sensitive or paramagnetic particles may include substances selected from the group consisting of iron, copper, manganese, ferrochrome, chromium, magnetite, hematite, PGM, and other precious metals.

[0031] A non-magnetic sheet may be provided between the conveyor bed and the conveyor belt. Without limitation, the non-magnetic sheet may be made of stainless steel.

[0032] The magnetic separator may include a plurality of magnetic bodies instead of only one magnetic body. At least a portion of one such body may be constructed as described above. For example, it may include rows of magnets with alternating polarities. Other portions of the magnetic body (or the entire length of other bodies) may have rows of magnets encapsulated in a unipolar orientation.

[0033] Compared with the above-described embodiments, certain embodiments of the magnetic separator may be configured to operate in an opposite orientation. Thus, they may be configured such that the separation of the particles occurs on the underside of the conveyor belt rather than on top of the conveyor belt.

[0034] In such embodiments, the feeding device may include a separate conveyor belt that is configured to serve as a feed belt across a pickup area beneath the conveyor belt of the separator. In use, the magnetically sensitive particles carried on the feed belt are adsorbed upward onto the underside of the conveyor belt of the separator.

[0035] The magnetic separator may include an adjustment mechanism that is configured to adjust the magnetic field applied through the conveyor belt. The adjustment mechanism may be configured to set a variable inclination of at least one magnetic body relative to the running plane of the conveyor belt.

[0036] The magnetic separator may include a chute device located beneath at least a portion of the conveyor belt for capturing and guiding the particles and other materials falling from the conveyor belt such that they can be collected. A pivotable vane or diverter may be positioned inside the chute device for diverting or guiding different components of the falling particles or other materials to different collection areas.

[0037] The conveyor belt may have a tripping formation spaced along its length. The tripping formation may include, for example, a laterally elongated cleat or bumper.

[0038] The disclosed magnetic separator may be applicable to separating components of a wet mixture or a dry mixture, the wet mixture or dry mixture including magnetic particles and magnetically sensitive particles, smaller magnetic particles, weakly magnetic particles, and non-magnetic particles.

[0039] According to another aspect of the present invention, a method for separating magnetically sensitive particles from a mixture is provided, the method comprising:

[0040] Operating a belt conveyor system to drive the conveyor belt around a conveyor bed arranged to support the conveyor belt in a running direction;

[0041] Feeding at least a portion of the mixture into the running conveyor belt in a mixture loading area;

[0042] Transporting the mixture from the mixture loading area to a particle recovery area on the conveyor belt adjacent to the conveyor bed; and

[0043] At least partially clearing the particles from the conveyor belt in the particle recovery area;

[0044] Wherein, the conveyor bed has a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveyor belt;

[0045] Wherein, the conveyor bed includes a magnetic body having an array of magnets, the magnets in the array being oriented transversely with respect to the longitudinal axis of the conveyor bed, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein, at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions having alternating magnetic polarities along the magnetic body in the running direction; and

[0046] Wherein, the step of conveying the mixture on the conveyor belt close to the conveyor bed includes conveying the mixture past at least some of the regions having alternating magnetic polarities of the magnetic body, thereby causing the particles to roll or tumble along the conveyor belt.

[0047] The method may further include conveying the mixture past at least one elongated partition, which is arranged or sandwiched between consecutive rows of repelling magnets in the magnet array. The partition may be oriented transversely with respect to the longitudinal axis of the conveyor bed. The partition may abut two rows of magnets and is arranged between the two rows of magnets.

[0048] The method may include conveying the mixture past a plurality of such partitions, which are arranged substantially parallel to each other and arranged in series along the length of the magnetic body in the running direction, and each partition extends across the width of the magnetic body.

[0049] The conveyor bed may be inclined or horizontal, and the method may include running the conveyor belt upward along an inclined plane from a mixture loading area to a particle recovery area.

[0050] The method may further include washing the mixture. The step of washing the mixture may include spraying a washing fluid onto the mixture as the mixture is conveyed upward along the inclined plane from the mixture loading area to the particle recovery area, thereby causing the washing fluid to flow downward along the conveyor belt, opposite to the upward running direction of the conveyor belt and the conveyed mixture.

[0051] The step of feeding the mixture onto the running conveyor belt may include feeding the mixture onto the conveyor belt as a pulp. The step of feeding the mixture onto the running conveyor belt may alternatively include feeding the mixture onto the conveyor belt as a dry material.

[0052] The step of feeding the mixture onto the running conveyor belt may include magnetically attracting at least a portion of the mixture to the lower side of the conveyor belt.

[0053] The step of at least partially removing particles from the conveyor belt may include a process selected from the following:

[0054] ·Scrape the particles off the running conveyor belt with a scraper;

[0055] ·Optionally, spray the washing fluid onto the particles using a spray bar to spray the particles off the running conveyor belt;

[0056] ·Allow the particles to fall from the underside of the running conveyor belt; and

[0057] ·Any combination of the above processes.

[0058] The step of at least partially removing particles from the conveyor belt in the particle recovery area may include collecting the particles in at least one chute device located below the conveyor system. Collecting the particles in the chute device may include guiding different components or portions of the particles into different areas of the chute device.

[0059] The method may include adjusting the magnetic field applied through the conveyor belt by tilting the magnet with respect to the running plane of the conveyor belt.

[0060] As described above, the corresponding embodiments of the components of the magnetic separator are also applicable to the disclosed method of separating magnetosensitive or paramagnetic particles from a mixture.

[0061] Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings. Description of the Drawings

[0062] In the drawings:

[0063] Figure 1 is a three-dimensional view of a first embodiment of the disclosed magnetic separator;

[0064] Figure 2 is Figure 1 a cross-sectional side view of the magnetic separator;

[0065] Figure 3 is Figure 1 a top view of the magnetic separator;

[0066] Figure 4 is Figure 1 a partial top view of the magnet of the magnetic separator;

[0067] Figure 5 is Figure 4 a schematic diagram of the magnetic field strength or magnetic flux density generated by the magnet;

[0068] Figure 6 is a schematic three-dimensional cross-sectional view of a second embodiment of the disclosed magnetic separator, which operates in an opposite orientation relative to the first embodiment;

[0069] Figure 7Yes Figure 6 Schematic side view of a magnetic separator that performs the process of separating magnetic particles from less magnetically sensitive and non-magnetic particles;

[0070] Figure 8 Yes Figure 6 Schematic cross-sectional side view of a magnetic separator showing its main magnetic body in a lowered or flat configuration; and

[0071] Figure 9 Yes Figure 6 Schematic cross-sectional side view of a magnetic separator showing its main magnetic body in an inclined configuration. Detailed Description of the Invention

[0072] Two exemplary embodiments of the magnetic separator are described below. The disclosed magnetic separator can be applied to separate magnetically susceptible valuable materials from gangue or other unwanted materials in a slurry or mixture of dry materials. It may be suitable for many separation applications, including, for example, removing magnetically susceptible impurities (contaminants) from a feed mixture containing the desired material, or removing magnetically susceptible particles or steel bodies from crushed ore, ROM, mining waste, slag, or "raw" or original mixtures or feeds.

[0073] Reference Figures 1 to 5 , Embodiment (1) of the disclosed magnetic separator includes a belt conveyor system that includes a closed-loop conveyor belt (2), a set of pulley rollers (3a; 3b), and a conveyor bed (4). The belt conveyor system is configured to drive the conveyor belt (2) to rotate around a set of pulley rollers (3a; 3b) in the running direction (A).

[0074] The conveyor bed (4) is arranged to support the conveyor belt (2) between the pulley rollers (3a; 3b). The conveyor bed (4) has a length defined by a longitudinal axis arranged substantially parallel to the running direction (A) of the conveyor belt (2). The conveyor bed (4) includes a magnetic body (5) and a back plate (6). The magnetic body (5) is shown in hidden detail in Figure 1 and Figure 3 and is positioned below the conveyor belt (2).

[0075] The running direction (A) of the conveyor belt (2) can be from the mixture loading area (7) towards the particle recovery area (10). The magnetic separator (1) can include a feeding device (8) mounted above the mixture loading area (7). In use, the feeding device (8) can be operated to deposit a slurry or other mixture containing magnetically susceptible particles (including magnetic, paramagnetic, or weakly magnetic particles) and non-magnetically susceptible particles on the conveyor belt (2) in the mixture loading area (7).

[0076] The magnetic separator (1) may further include a material removal device, which includes a scraper (9) installed in the particle recovery area (10) of the belt conveyor system. The leading edge of the scraper (9) may be biased against the conveyor belt (2) during operation, so that when the conveyor belt (2) passes under the leading edge of the scraper (9), the sludge of magnetically sensitive particles is stripped from the conveyor belt (2) by the scraper (9). The scraper (9) may be installed to extend across the width of the conveyor belt (2). Other suitable cleaning devices (not shown) may be used instead of or in addition to the scraper (9), such as wipers, ejectors, blowers or suction devices.

[0077] The magnetic separator (1) may further include a washing device (11) for washing the pulp or other mixture when the pulp or other mixture is conveyed by the conveyor belt (2). The washing device (11) may be located between the mixture loading area (7) and the particle recovery area (10) of the belt conveyor system. The washing device (11) may include an ejector for ejecting a washing fluid such as water onto the pulp or mixture to wash away weakly magnetic or non-magnetic mineral gangue or other unwanted particles. The ejector and the belt conveyor system may be configured such that the washing fluid flows in a direction substantially opposite to the running direction (A) of the conveyor belt (2).

[0078] As best seen in Figure 3 and Figure 4 the magnetic body (5) may include an array of individual magnets (12) arranged in rows (15). Figure 3 and Figure 4 The arrow B in

[0079] Figure 4 shows how the rows (15) of magnets (12) are oriented transversely or crosswise with respect to the longitudinal axis of the conveyor bed (4) and the running direction (A) of the conveyor belt (2). In addition, the polar axes of each magnet (12) (i.e., the axis extending between its north and south poles) are arranged substantially parallel to the longitudinal axis of the conveyor bed (4) and the running direction (A) of the conveyor belt (2).

[0080] Figure 5Schematically shows how the magnetic field strength or magnetic flux density generated by the disclosed magnetic separator (1) can be configured across the magnetic body (5). The configuration of the disclosed magnetic separator (1) is such that the magnetic field strength or magnetic flux density provided by the magnet array in the magnetic body can be substantially constant along each transverse pole segment of the magnetic body (i.e., across the width of the magnetic body). This is generated by the orientation of the magnets (12) relative to the running direction (A) of the conveyor belt (2). The magnetic body (5) generates lines of substantially equal magnetic field strength or magnetic flux density extending across substantially the entire width of the magnetic body (5). Thus, when the material flows over the magnetic body, the particles and other materials on the conveyor belt will almost invariably cross the high points of the magnetic field strength.

[0081] In contrast, if the linearly extending magnetic poles of the magnetic body are alternatively arranged longitudinally, i.e., parallel to the running direction of the conveyor belt (instead of transversely to the conveyor belt as currently taught), the magnetic field strength or magnetic flux density provided by the magnet array will not be constant across the width of the magnetic body. This will have the undesirable effect that dead spots or weak points will exist between the magnetic poles, extending longitudinally in the running direction of the conveyor belt, which may allow the material to pass through without being captured and run directly to the tailings. Additionally, in such a longitudinal arrangement, it can be expected that the magnetic field strength or magnetic flux density will decrease towards the sides of the magnet array. This will limit the ability and effectiveness of the magnetic body to attract magnetic and paramagnetic particles and pull them towards the particle recovery area.

[0082] Depending on the specific application for which the magnetic separator (1) is to be used, the magnets (12) of the magnetic body (5) can be high - grade or low - grade magnets. In some embodiments, for example, the magnets (12) can be made of (or can include) rare earth elements, ferrites, or magnetite. At least some of the magnets (12) can include neodymium magnets (also known as NdFeB, NIB, or Neo magnets), or samarium - cobalt magnets (also known as SmCo magnets). However, standard anisotropic ferrite magnets, ceramic magnets, or ferromagnetic materials are also suitable for applications that do not require high magnetic field strength, such as the extraction of ferrochrome alloys, magnetite, or ferrosilicone.

[0083] At least some of the magnets (12) in the array can each have approximate dimensions within the following ranges:

[0084] · Length (l): 5 - 65 mm;

[0085] · Width (w): 20 - 200 mm; and

[0086] · Height / Depth (d): 20 - 200 mm;

[0087] Where:

[0088] - The length (l) of the magnet (12) is measured parallel to the longitudinal axis of the magnetic body (5), i.e., parallel to the running direction of the conveyor belt (2);

[0089] - The width (w) of the magnet (12) is measured parallel to the width of the magnetic body (5), i.e., transverse to the running direction of the conveyor belt (2); and

[0090] - The depth (d) of the magnet (12) is measured by the depth of the magnetic body (5); i.e., by the height or thickness of the magnetic body (5) and perpendicularly away from the conveyor belt (2).

[0091] In some embodiments, and not limited to the examples given, at least some of the magnets (12) may each have approximate ratios of length × width × depth dimensions selected from the group consisting of:

[0092] · 10 × 22 × 22;

[0093] · 40 × 65 × 65;

[0094] · 60 × 80 × 80;

[0095] · 45 × 65 × 67.5;

[0096] · 60 × 85 × 87.5;

[0097] · 25.4 × 100 × 150;

[0098] · 25.4 × 50 × 150;

[0099] · 55 × 75 × 100;

[0100] · 25.4 × 105 × 155; and

[0101] · 30 × 105 × 155.

[0102] In a preferred embodiment, the above ratios may represent dimensions in millimeters (mm); however, it should be understood that other units of dimension are feasible depending on the scale of the device, as long as the above ratios are maintained.

[0103] Magnets (12) having dimensions with these ratios can provide a favorable magnetic flux field or magnetic pattern compared to other dimensional arrangements. The described features can enable regions of alternating magnetic polarity and linear regions of concentrated magnetic field strength or flux to pass through or penetrate the material of the conveyor belt (2) and attract magnetically sensitive particles to the conveyor belt (2).

[0104] The magnetic field strength or magnetic flux density provided by the array of magnets (12) in the magnetic body (5) is operably more than 1.8 Tesla (18,000 Gauss). It can be in the range of about 1.8 to about 2.5 Tesla (18,000 to 25,000 Gauss), as measured immediately above the conveyor bed (4) (below the conveyor belt (2)).

[0105] The magnetic field strength or magnetic flux density penetrating the conveyor belt (2) from the magnetic body (5) can exceed 1.4 Tesla (14,000 Gauss). As measured on the upper load side of the conveyor belt (2) under its operating conditions (i.e., on the side of the conveyor belt (2) opposite to the side facing the conveyor bed (4)), the field strength can be in the range of about 0.7 to about 2.0 Tesla (7,000 to 20,000 Gauss).

[0106] To reduce the Gauss rating or magnetic flux achieved through the conveyor belt (2), it is feasible to use a thicker conveyor belt or add one or more non-magnetic sheets between the magnetic body (5) and the conveyor belt (2). For example, these sheets can be made of stainless steel. This has the effect of increasing the "air gap" or "air spacing" between them and reducing the magnetic intensity or strength achieved through the conveyor belt (2), such that the required strength can be set or adjusted according to the main requirements for achieving separation. For example, an embodiment of the magnetic separator suitable for separating ferrochrome can be set to start at about 0.5 Tesla (5,000 Gauss) measured at the surface of the conveyor belt, but since both ferrochrome and slag can be magnetic at 0.15 Tesla (1,500 Gauss), for example, the strength may need to be reduced to about 0.09 Tesla (900 Gauss) so that only the more magnetic ferrochrome is captured and then less magnetic slag is discharged.

[0107] A plurality of elongated partitions (13) (also known as accelerator plates or fins) are arranged or sandwiched between consecutive rows (15) of the repelling magnets (12) in the array. Similar to the rows (15), the partitions (13) are also transversely oriented with respect to the longitudinal axis of the conveyor bed (4) and the running direction (A) of the conveyor belt (2). Thus, the partitions (13) are generally oriented parallel to the arrow B in the figure.

[0108] The partitions (13) are generally arranged in a regular spaced sequence advancing along the length of the magnetic body (5), with each partition (13) extending transversely or crosswise across the width of the magnetic body (5).

[0109] Each partition (13) can be adjacent to two rows of magnets (12), with the partition arranged between the two rows of magnets.

[0110] In certain non - limiting embodiments, each separator (13) can have a thickness in the range of from about 1 mm to 30 mm, optionally from about 2 mm to about 6 mm, and optionally from about 2.5 mm to about 4 mm. Thicknesses within these ranges can facilitate magnetic field penetration through the conveyor belt (2). Thinner plates allow for higher field intensities, but can be disadvantageous as they can reduce field penetration through the conveyor belt (2).

[0111] In certain non - limiting embodiments, at least some of the separators (13) can each be made entirely or partially of low - carbon steel or permendur. The steel can have an iron content of about 98%. At least some of the separators can alternatively or additionally be made entirely or partially of alternative alloys, depending on the required acceleration, i.e., the concentration or focusing of the magnetic field and the tipping force required to be applied to the magnetically sensitive particles.

[0112] In other non - limiting embodiments, at least some of the separators (13) can be made entirely or partially of one or more non - magnetic materials. The use of non - magnetic materials can be suitable for controlling the effective "air gap" or "air spacing" between the magnets when the magnetic separator is used in certain applications.

[0113] Before assembling the magnetic bodies (5) (i.e., before fitting each separator (13) into its appropriate position between the rows of repelling magnets (12), which are designed to be separated), each separator (13) should be advantageously thoroughly cleaned. All oxide layers on the steel should be removed. The cleaning can be carried out by means of a surface grinder or a polishing machine.

[0114] As best seen in Figure 1 and Figure 2 The belt - conveyor system of the magnetic separator (1) can be configured such that the conveyor belt (2) and the conveyor bed (4) are operably inclined, but it should be understood that embodiments with a horizontal orientation also fall within the scope of the present invention. Embodiments with an inclined configuration are advantageous because they allow water or other washing fluids sprayed onto the pulp by the washing device (11) to flow downward along the inclined conveyor belt (2), passing over and through the pulp or other mixture as the pulp or other mixture is carried upward along the inclined plane on the conveyor belt (2). This action facilitates the washing of the pulp or other mixture because the water flows counter - currently to the direction of travel of the magnetically sensitive particles carried upward along the inclined plane. In certain embodiments, the inclination of the conveyor bed (4) and the conveyor belt (2) can be in the range from about 5° to about 60° from horizontal. For example, an inclination of about 10° can be suitable for separating Cr particles, an inclination of about 12° to 15° can be suitable for separating Fe particles, an inclination of about 30° can be suitable for separating ferrochrome particles from the pulp, and an inclination of 45° can be suitable for separating Fe particles from a dry mixture.

[0115] In other embodiments applicable to processing dry mixtures of valuable and valueless materials or particles, the inclination of the conveyor bed (4) and the conveyor belt (2) can be in the range of about 20° to about 60° to the horizontal.

[0116] In additional embodiments that may be suitable for processing wet mixtures of valuable and valueless materials or particles, the inclination of the conveyor bed (4) and the conveyor belt (2) can be in the range from about 5° to about 30° to the horizontal.

[0117] The magnet (12) of the magnetic body (5) generally abuts the back plate (6) and can be fastened to the back plate (6) using bolts (14). However, it should be understood that the back plate (6) can be attached to the magnetic body (5) by other means (e.g., adhesives or welding).

[0118] A box or other container (16) can be provided below the scraper (9), and when the particle-containing sludge is scraped off the belt (2) during operation, the particle-containing sludge can fall into the box or other container and be collected.

[0119] The operable upper parts of the conveyor bed (4), the magnetic body (5), and the conveyor belt (2) can each define a length and a width. The operable upper part of the conveyor belt (2) can have a length in the range of about 2 m to about 4 m and a width in the range of about 1 m to about 3 m; optionally a length of about 3 m to about 4 m and a width in the range of about 1.5 m to 2.7 m.

[0120] In certain non-limiting embodiments, the conveyor belt (2) can have a thickness of about 1.3 mm to about 6 mm.

[0121] The conveyor belt (2) can advantageously be equipped with straight or flat sidewalls. This type of sidewall may be superior to the "accordion-style" sidewalls found in some belt conveyor systems because the latter type can allow dust to be trapped in the gap between the sidewall and the conveyor belt, which is then not affected by the magnetic body and can be discharged to the magnetic side, thus contaminating the product.

[0122] The conveyor belt (2) can be smooth, i.e., generally flat and smooth. It typically can have no baffle blocks, splints, or other irregular structures mounted across the entire width of the conveyor belt. This type of structure can trap and carry dirt, thus reducing the cleaning time for the magnetic body and also contaminating the product.

[0123] The joint or seam between the ends of the conveyor belt (2) should not be thick or have steps. The joint should be well spliced and should have the same thickness as the conveyor belt.

[0124] The conveyor bed (4) and the magnetic body (5) can each have a width that generally matches or slightly exceeds the width of the conveyor belt (2).

[0125] The transfer bed (4) and the magnetic body (5) can each have a length that generally matches the distance between the pulley rollers (3a; 3b) of the conveyor belt (2).

[0126] During operation of the disclosed magnetic separator (1), the partition (13) can be used to concentrate the magnetic field strength or flux density associated with the magnet (12) into a series of generally linear regions that are oriented transversely to the longitudinal axis of the transfer bed (4) and spaced apart from each other along the length of the transfer bed (4). This configuration is schematically shown in Figure 5 which. The linear regions extend across the width of the magnetic body (5). The positioning and arrangement of the linear magnetic regions can generally correspond to the positioning and arrangement of the partition (13).

[0127] Magnetically sensitive particles are adsorbed by the magnetic field towards the carrying surface of the conveyor belt (2) and are pulled upwards along the inclined plane towards the scraper (9) together with the conveyor belt (2), while the less magnetically sensitive substances in the mineral gangue are not adsorbed to the conveyor belt (2) and can therefore be washed down the inclined plane as waste or as a valuable material and leave the conveyor belt (2). As previously mentioned, in some modes of practicing the present invention, the non-magnetically sensitive particles are the valuable material and the magnetically sensitive particles need to be removed from the mixture.

[0128] At the same time, the spaced-apart linear regions of concentrated magnetic field strength or flux density extending across the width of the transfer bed (4), and the changes and alternating magnetic polarities experienced by the pulp on the conveyor belt (2) as it is carried onto the magnetic body (5) can be expected to cause the magnetically sensitive particles in the pulp to roll or tumble on the conveyor belt (2) as they are conveyed upwards towards the scraper (9) in the particle recovery region (10) on the conveyor belt (2). This rolling or tumbling action can be expected to facilitate the agitation and separation of those particles from the unwanted gangue and other materials surrounding or enclosing them. Thus, this action can result in a cleaner final product. In contrast, if it is assumed that the linearly extending poles of the magnetic body are arranged parallel to the running direction of the conveyor belt (instead of transversely to the conveyor belt as currently taught), it is expected that the particles conveyed on the conveyor belt will not experience the rolling or tumbling effect achieved by the magnetic separator of the present teachings. It is expected that the particles captured by the conveyor belt will easily capture the non-magnetic material between the magnetic materials and then the non-magnetic material will be carried along with the magnetic materials, thus contaminating the product.

[0129] The magnetic separator (1) can be used, in particular but not exclusively, for washing valuable substances from tailings, or for concentrating raw or virgin materials to obtain minerals or metals of commercial grade.

[0130] In addition, compared with other types of magnetic separators in which the magnets (12) and the magnetic flux density are arranged along the length of the conveyor bed (4) (i.e., parallel to the running direction of the conveyor belt (2)), the transverse or cross arrangement of the magnet rows (12) and the accelerator plates (13) and thus the transverse or cross arrangement of the linear regions of the magnetic flux density can suppress or reduce the formation of stripes on the conveyor belt (2).

[0131] Figures 6 to 9 Another embodiment (601) of the disclosed magnetic separator is shown. This embodiment differs from the previously described embodiment (1) in the following main aspects:

[0132] · Embodiment (601) has an inverted configuration, i.e., it operates upside down compared to embodiment (1). The separation of the particles occurs on the lower side of the conveyor belt (603) rather than on the top of the conveyor belt.

[0133] · Embodiment (601) includes two magnetic bodies instead of one magnetic body. There is a pickup body (605a) and a main body (605b). At least a part of the main body (605b) has a structure similar to the above-mentioned magnetic body (5), i.e., the magnetic poles of its magnets alternate as north, south, north, south, etc. Partition plates (607) are provided between some consecutive rows of magnets. Without limiting the generality of the suitable dimensions of these plates, they can each have a thickness similar to that of the above-mentioned partition plate (13) for the partition plate. Similarly to the plate (13), the plate (607) can be made entirely or partially of magnetic material, non-magnetic material, or a combination thereof. Such materials can include, for example, low-carbon steel, permendur alloy, other suitable alloys, or appropriate non-magnetic materials. However, different from the case of embodiment (1), the partition plates in the shown embodiment (601) only exist in one section of the main magnetic body (605b), rather than along its entire length. Some consecutive rows of magnets are arranged in direct contact with each other (not sandwiched between partition plates), while other magnets are separated by partition plates. However, it should be understood that partition plates can be provided between each pair of rows if required for a specific application.

[0134] As Figure 7 shown, an additional conveyor belt (651) is provided as part of the feeding device. This conveyor belt (referred to herein as the feeding belt) passes through the pickup area (653) below the main conveyor belt (603) (“separation belt”) of the magnetic separator (601). The feeding belt (651) can run in the same direction as the separation belt (603), as Figure 7 shown, or the feeding belt can run transversely to the separation belt (not shown).

[0135] Figure 7Shows the operation of an embodiment (601) of a magnetic separator. The feed belt (651) and the separation belt (603) run closely to each other. The separation belt (603) passes through the pickup area (653), just above the feed mixture (655) being brought onto the feed belt (651). The purpose of this part of the machine is to adsorb all or most of the magnetic material in the feed mixture (655) and strip it from the feed belt (651) so that it adheres to the underside of the running separation belt (603). At the same time, most of the non-magnetic particles remain on the feed belt (651) and are carried away to be collected for use or discarded elsewhere.

[0136] The pickup magnet (605a) located above the feed belt (651) provides a long magnetic field to provide maximum pickup intensity at the operating gap where the feed mixture (655) passes under the pickup magnet on the feed belt (651). Thus, since a monopole typically provides the longest effective field length, the magnets in the pickup body are usually encapsulated in a monopole arrangement oriented north or south. However, in some embodiments (not shown), at least a portion of the pickup body may alternatively be configured similar to the magnet (5) described previously, i.e., it may include rows of magnets with alternating polarities. This arrangement can provide a higher gauss rating, which may be desirable in some cases, such as for processing certain ores.

[0137] In the use of the magnetic separator (601), magnetically sensitive materials that do not reach the end of the main magnet (605b) fall as "intermediate products" ( Figure 7 657 in) from the underside of the conveyor belt. The machine is set up so that these intermediate products fall as the conveyor belt passes through the intermediate product discharge and collection area (659). There may also be some non-magnetic materials here that are trapped or agglomerated by the magnetic material in the pickup area (653). This non-magnetic material will fall from the conveyor belt relatively quickly as the magnetic particles tumble and rotate.

[0138] Stronger magnetic particles ( Figure 7 661 in) remain adsorbed to the underside of the separation belt (603). These materials continue along the underside of the conveyor belt (603), running under the main magnet (605b). Eventually, they reach an area of lower magnetic force where the upward pull is not sufficient to hold them on the underside of the conveyor belt (603). They fall off the conveyor belt and can be collected in the magnetically valuable material discharge and collection area (663). Materials that stick to the conveyor belt until the end of the main magnet can be expected to be the purest materials, i.e., the most magnetically sensitive materials. For example, this could be high-grade iron. The separator can be set up to achieve a marketable grade using the adjustment mechanism described further below.

[0139] A chute apparatus (665) may be provided below the separation zone (603). Generally, the chute apparatus is positioned below the portion of the conveyor belt that passes beneath the main magnetic body (605b). The chute apparatus (665) is configured to capture particles falling from the conveyor belt. A pivotable vane or diverter (667) may be provided inside the chute apparatus (665) to divert or direct different components of the falling particles into separate collection areas. For example, the length of the central collection area (659) may be adjusted by pivoting the vane (667) such that a greater or lesser amount of the less magnetically sensitive intermediate product will be deflected by the first side of the vane and fall into this area as required. The more magnetically sensitive components will then travel further along the underside of the conveyor belt until they drop and are directed by the other side of the vane (667) into the magnetically valuable material collection area (663).

[0140] The depicted chute apparatus (665) defines only two collection areas (659, 663), the collection area closest to the feed conveyor being the intermediate product collection area and the other collection area being the magnetically valuable material collection area. However, it should be understood that the apparatus may be configured to define more than two collection areas depending on the type of material being processed. The multiple areas may be defined by multiple different chutes, or a single chute may define three or more separate collection areas, for example, an area for weak intermediate products, an area for strong intermediate products, and an area for magnetically valuable materials. The separate collection areas may be configured to feed separate conveyor belts or bins (not shown) to collect the separated components.

[0141] As in the case of the embodiment (1) of the magnetic separator, the inverted variant (601) also applies a rolling or tumbling action to the magnetic material mass carried by the separation zone (603), although in this case the rolling action occurs on the underside of the conveyor belt. As previously mentioned, the rolling action is caused in part by the changing polarity of the magnets in the main magnetic body (605b) and in part by a tumbling structure such as a turning bar provided on the conveyor belt (discussed further below). The rolling action provides a cleaning action. When the separation zone runs in the direction "A" as shown, the less magnetically sensitive particles are dislodged or agitated from the mixed material mass. Figure 6 The less magnetically sensitive particles are dislodged or agitated from the mixed material mass when the separation zone runs in the direction "A" as shown.

[0142] The illustrated embodiment of the magnetic separator (601) also includes an adjustment mechanism for adjusting the magnetic field strength applied by the main magnetic body (605b) via the conveyor belt (603). This mechanism allows the inclination of the main body to be adjusted and set by pivoting the main body (605b) about the horizontal hinge (669). Pivoting the main body upwards results in a decrease in the magnetic field strength or Gauss rating applied via the conveyor belt (603) as the conveyor belt (603) passes from the intermediate product collection area towards the magnetic cleaning area above the valuable material collection area (663). Figure 8 and Figure 9 The main magnetic body (605b) is shown set at two different inclination conditions. In Figure 8 , the main body has been lowered such that it lies flat above the conveyor belt (603). This orientation provides stronger magnetic adsorption via the conveyor belt. However, in Figure 9 , the main body (605b) has been raised to an inclined orientation where its free end is spaced from the conveyor belt. This orientation, combined with a more dispersed packing of the magnets towards the free end of the main body (successive rows of magnets being separated by partitions), causes the magnetic adsorption to drop more quickly as the conveyor belt (603) travels towards the free end of the main body.

[0143] It should be understood that other adjustment mechanisms for changing the strength or Gauss rating of the applied magnetic field can be implemented. For example, weaker magnets can be used towards the free end of the main magnetic body.

[0144] The separating belt (603) can have a turning structure attached to or integrated with it. For example, the separating belt can have laterally elongated turning bars or baffles ( Figure 6 671 in

[0145] spaced along its length).

[0146] During the use of the magnetic separator (601), the lower side of the separating belt (603) traveling below the pick-up body (605a) adsorbs and carries the magnetic material away from the feed belt (651) and towards the main magnetic body (605b), where the magnetic poles of the magnets start to alternate.

[0147] When the material is carried under the alternating magnetic poles of the main magnet (605b), the material is flipped and agitated by the turning bar (671). This action can help impart the desired rolling or tumbling motion to the feed material carried on the underside of the conveyor belt. This provides a cleaning effect and can help break up material chunks. Less magnetically sensitive particles can be loosened and fall into the intermediate product collection area (659). The collected intermediate product can be reprocessed. For example, they can be crushed to release more non-magnetic material from the iron and then passed through the same magnetic separator again, or they can be mixed with other materials, including non-magnetic or magnetic ones, depending on the target grade.

[0148] After passing through the intermediate product collection area (659), the remaining material that is more magnetic than the intermediate product continues along under the conveyor belt until it reaches an area of weaker magnetism, where, for example, the raised free end of the pivoting body is more spaced apart from the conveyor belt. The material that now falls from the magnet due to the magnetism of the magnet being insufficient to hold it to the conveyor belt falls by gravity into the downstream area of the chute device (665) and is guided through the magnetically valuable material collection area (663).

[0149] Without limiting the generality of the suitable applications of the magnetic separator (601), the feed mixture can include iron ore or iron slag from a foundry or furnace. In such an application, the intermediate product can include a mixture of slag and iron that is still bound together. If the feed material contains, for example, 40% iron and 60% impurities, the impurities will fall into the intermediate product collection area (659). Here, the magnetic field strength or Gauss rating applied by the conveyor belt will be set low enough to release most of the impurities and only attract the better quality particles. These can contain 60% or more iron, for example, allowing them to pass through the intermediate section and travel further towards the free end of the main magnet (605b) before falling from the belt.

[0150] It should be understood that the disclosed embodiments of the magnetic separator (1; 601) are applicable to many other applications. These include, for example, separating ferrochrome from magnetite in a dry mixture, or removing magnetically sensitive particles or contaminants from other feed mixtures, such as those described in the introduction to this section.

[0151] The present invention also provides a method for separating magnetically sensitive particles from the above-mentioned mixture. The method includes the steps of: operating a belt conveyor system to drive the conveyor belt in a running direction close to a conveyor bed arranged to support the conveyor belt; feeding at least a portion of the mixture onto the running conveyor belt in a mixture loading area; and transferring a portion of the mixture close to the conveyor bed from the mixture loading area to a particle recovery area. The method can also include at least partially clearing the particles from the conveyor belt in the particle recovery area.

[0152] The conveyor bed can be as described above, and the step of conveying the mixture adjacent to the conveyor bed can include conveying the mixture past regions of the magnetic body having alternating magnetic polarities, such that the particles roll or tumble along the conveyor belt.

[0153] The method can further include conveying the portion of the mixture past at least one elongate separator arranged or sandwiched between consecutive rows of repelling magnets in the magnet array. Advantageously, the separator can be transversely oriented with respect to the longitudinal axis of the conveyor bed. The separator can abut two rows of magnets, with the separator being arranged between the two rows of magnets, as shown in the figure. The method can include conveying the mixture past a plurality of such separators, which are arranged generally parallel to each other and in series along the length of the magnetic body in the direction of operation, each separator extending across the width of the magnetic body.

[0154] As described above, the conveyor bed can be operably inclined, and the method can include running the conveyor belt up the inclined plane from the mixture loading region to the particle recovery region.

[0155] The method can further include washing the pulp or other mixture conveyed on the conveyor belt. The step of washing the mixture can include spraying or otherwise discharging a washing fluid, such as water, onto the mixture as the mixture is conveyed up the inclined plane from the mixture loading region to the particle recovery region. The washing fluid can then flow down the conveyor belt, opposite to the upward direction of travel of the conveyor belt and the conveyed mixture.

[0156] Typically during operation, the valuable material being sought to be recovered will move upwards towards the top of the inclined magnetic body on the conveyor belt, and the material washed off the conveyor belt by the flow of pulp and water will be waste or tailings. For example, when separating iron which can be in the form of magnetite or hematite, this mode of operation will apply. However, other modes of operation also fall within the scope of the present invention. For example, PGMs are generally non-magnetic. In this case, the magnetic body is used to upgrade the PGM concentrate by removing magnetically sensitive particles such as chromium. The material adsorbed by the magnetic body (which moves towards the operable upper end of the magnetic body) is discarded, and the tailings (running to the operable lower end of the magnetic body) are recovered as the desired product. When recovering certain minerals, such as when separating a mixture of iron and mineral sand, the different desired products can travel in opposite directions.

[0157] Examples of separation processes involving iron are given below. A strong magnet will pull magnetite and hematite. Magnetite is susceptible to about 0.15 tesla (1500 gauss), while hematite is susceptible to about 1.0 tesla (10000 gauss). For example, at a first pass of about 1.5 tesla (15000 gauss), both will be captured. Then a second pass can be made at about 0.15 tesla (1500 gauss) such that the magnetite will move towards the top and the hematite towards the bottom, so that the two are now separated, but both the top and bottom are marketable products.

[0158] The step of feeding the mixture onto a running conveyor belt can include feeding it onto the conveyor belt as a slurry or as a dry material. The mixture can be fed onto the conveyor belt and evenly spread thereon.

[0159] The step of feeding at least a portion of the mixture onto a running conveyor belt can include magnetically attracting that portion of the mixture to the underside of the conveyor belt.

[0160] The step of at least partially removing particles from the conveyor belt can include scraping the particles off the running conveyor belt. A scraper can be used for this purpose. Alternatively or additionally, the step of at least partially removing particles from the conveyor belt can include spraying the particles off the running conveyor belt. A spray bar can be used for this purpose. A washing fluid can be sprayed onto the particles.

[0161] Alternatively or additionally, the step of at least partially removing particles from the conveyor belt can include allowing the particles to fall from the underside of the conveyor belt into a separate area. Thus, the step can include dividing the components of the particles and other materials falling from the conveyor belt. It can also include collecting the particles and other materials in different areas of a chute device located below the conveyor belt.

[0162] The method can include the step of adjusting the magnetic field applied through the conveyor belt by tilting the magnet with respect to the running plane of the conveyor belt.

[0163] In a specific application, and without limiting the generality of possible applications, the disclosed magnetic separator and method can be used to separate and extract magnetically sensitive particles, such as iron, chromium, manganese, copper, or other metals, from crushed ore or gangue in a slurry or tailings.

[0164] The disclosed magnetic separator can be effectively used for tailings or mining waste as well as ROM or "as-mined" or raw mixtures. The present invention can be used as an alternative to existing spiral separators, gravity separators, and other conventional methods and systems applied to existing mining processes.

[0165] As another example, a magnetic separator can be used to separate the components of a slag mixture. The high-quality iron in the mixture that is suitable for melting and reuse can be separated from impurities, tailings, and other non-magnetic materials. To perform this type of separation, the slag mixture is typically first crushed and agitated, which allows the slag to fall off the iron because the slag is softer than the iron. This facilitates the release of the slag and non-magnetic substances from the iron. Then, the magnets in the separator (601) are used to concentrate the available iron. The materials not adsorbed by the feed belt (651) will include non-magnetic components with no iron content or very little iron content. This material can be suitable for agricultural applications provided that most of the iron has been removed and the Calcium Carbonate Equivalent (CCE) value is high.

[0166] The ability to adjust the magnetic flux field can allow for efficient and cost-effective separation. Additionally, the disclosed magnetic separator can be more cost-effective than other devices and separation techniques, provided that certain embodiments can operate with a relatively small motor, for example, a motor rated in the range of 1.5 kW to 2 kW, or a small solar motor. Further, the water or other wash fluids used with the disclosed magnetic separator can be recycled and reused, thereby reducing the overall ecological footprint of the system. Thus, the disclosed system and method can provide a sustainable and environmentally friendly (“green”) technology.

[0167] In one test, a scaled-down embodiment of the separator (601) outperformed the jig and operated without the need for any water in the feed mixture.

[0168] The foregoing description has been presented for purposes of illustration; it is not intended to be exhaustive or to limit the invention to the precise form disclosed. Those skilled in the relevant art will appreciate that many modifications and variations are possible in light of the above disclosure.

[0169] For example and without limiting the generality of the possible variations, the rows of magnets in the magnet body of an alternative embodiment (not shown) need not consist of multiple magnets. Thus, each row can alternatively be formed by a single elongated magnet extending across the width of the magnet body, rather than by a linear arrangement of multiple smaller magnets.

[0170] In another example of different variants (not shown) that fall within the scope of the present invention, at least some adjacent rows of magnets can be arranged with different magnetic poles facing and attracting each other. Thus, compared to an embodiment that employs a single (solid) magnet extending between each pair of consecutive accelerator plates, multiple thinner magnets can alternatively be used to form a larger composite magnet, where each composite magnet is located between a pair of accelerator plates. For example, two adjacent rows of magnets can be disposed between a pair of spaced-apart separator plates, and the magnetic poles in these two inner rows are positioned to attract each other while repelling the two rows of magnets surrounding them on either side of the two separator plates. However, it is expected that a solid magnet would be advantageous compared to such a composite embodiment because a solid magnet can provide more power or magnetic field strength than two or more smaller magnets joined or adjacent to each other.

[0171] In another non-limiting example of a variant (not shown), the conveyor belt can be configured to run and circulate in a plane rather than a parallel orientation in the manner of an overlapping slat turntable commonly used for airport baggage handling. However, due to the need for a gap between the overlapping slats through which pulp and particulate material may be lost, embodiments of this type of conveyor belt are less preferred than an endless loop belt conveyor.

[0172] Although permanent magnets are used to construct the magnetic bodies of the illustrated magnetic separator, in other embodiments, it may be appropriate to use other types of magnets. For example, depending on the intended application of the magnetic separator and the required magnetic field strength, temporary magnets or electromagnets can be used instead of or in addition to permanent magnets.

[0173] It should also be understood that a plurality of discrete magnetic bodies can be provided along the length of the conveyor bed, adjacent to or spaced apart from each other.

[0174] It should further be understood that in certain embodiments (not shown), the conveyor bed (and thus the magnetic bodies) can be operatively arranged above rather than below the conveyor belt.

[0175] In addition, in certain alternative embodiments (not shown), the magnetic assembly does not need to include a flat conveyor bed. For example, the magnetic assembly can be of a generally cylindrical configuration, including a drum surrounded by magnetic bodies. In such an embodiment, the drum can be arranged to function as a roller around which the conveyor belt can run. Additionally, in certain embodiments, the drum can be arranged to function as a drive pulley.

[0176] In other embodiments (not shown), the conveyor system need not be limited to a belt conveyor system; that is, the magnetic separator can be of a type known as a drum separator. In such an embodiment, the conveyor element can include a drum, and the cooperating magnetic assembly (and magnetic bodies) can be provided as one or more arcuate shoes positioned within the drum. In such an embodiment, the direction of travel of the drum and the longitudinal axis of the magnetic bodies (the rows of magnets being arranged transversely with respect to the longitudinal axis) can be tangential to the circumference of the drum.

[0177] The language used in the specification has been principally selected for readability and guidance, and may not have been selected to depict or circumscribe the subject matter of the invention. Accordingly, the scope of the invention is intended to be limited not by this detailed description, but rather by any claims of an application based thereon. Thus, the disclosure of embodiments of the invention is intended to be illustrative rather than limiting of the scope of the invention as set forth in any claims that will issue on an application based thereon.

[0178] Finally, throughout the specification, unless the context requires otherwise:

[0179] · the word "comprising" or variations such as "comprises" or "having" will be understood to imply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers; and

[0180] · the phrase "magnetosensitive" as used in relation to magnetosensitive particles or other materials will be understood in its broadest sense and will not be limited to include only magnetic, paramagnetic, and weakly magnetic particles and other materials.

Claims

1. A magnetic separator, the magnetic separator comprising a conveying system configured to drive a conveying element in a running direction, and a cooperating magnetic assembly arranged near the conveying element; The magnetic assembly has a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveying element; and The magnetic assembly includes at least one magnetic body having an array of magnets; Among them, The rows of magnets in the array are transversely oriented with respect to the longitudinal axis of the magnetic assembly, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions of alternating magnetic polarity along the magnetic body.

2. A magnetic separator, the magnetic separator comprising: A belt conveying system configured to drive a conveyor belt in a running direction; And A conveying bed arranged to support the conveyor belt, the conveying bed having a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveyor belt; The conveying bed includes at least one magnetic body having an array of magnets; Wherein the rows of magnets in the array are transversely oriented with respect to the longitudinal axis of the conveying bed, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions of alternating magnetic polarity along the magnetic body.

3. The magnetic separator according to claim 2, wherein, The magnetic body includes at least one elongated partition arranged between consecutive rows of repelling magnets in the array, the partition being transversely oriented with respect to the longitudinal axis of the conveying bed.

4. The magnetic separator according to claim 3, wherein, The partition abuts two rows of magnets and is arranged between the two rows of magnets.

5. The magnetic separator according to any one of claims 2 to 4, wherein, The conveying bed further includes a back plate.

6. The magnetic separator according to any one of claims 2 to 5, wherein, The magnetic separator further includes at least one magnetic body having rows of magnets encapsulated in a unipolar orientation.

7. The magnetic separator according to any one of claims 2 to 6, wherein, The belt conveying system is configured such that the conveying bed and the conveyor belt have an adjustable and operably tiltable orientation.

8. The magnetic separator according to any one of claims 2 to 7, the magnetic separator including an adjustment mechanism configured to adjust the magnetic field applied through the conveyor belt, the adjustment mechanism being configured to set a variable tilt of the magnetic body with respect to the running plane of the conveyor belt.

9. The magnetic separator according to any one of claims 2 to 8, wherein, The magnetic separator includes a chute device located below at least a portion of the conveyor belt, and pivotable vanes are located in the chute device.

10. The magnetic separator according to any one of claims 2 to 9, wherein The conveyor belt has a turning structure spaced along its length.

11. A method for separating magnetically sensitive particles from a mixture, the method comprising: Operating a belt conveying system to drive the conveyor belt in a running direction around a conveying bed arranged to support the conveyor belt; Feeding at least a portion of the mixture into the running conveyor belt in a mixture loading area; Transferring the mixture from the mixture loading area to a particle recovery area on the conveyor belt near the conveying bed; And At least partially remove the particles from the conveyor belt in the particle recovery area; wherein the conveyor bed has a length defined by a longitudinal axis arranged substantially parallel to the running direction of the conveyor belt; wherein the conveyor bed includes a magnetic body having an array of magnets, the magnets in the array being laterally oriented with respect to the longitudinal axis of the conveyor bed, wherein the polar axes of each magnet are arranged substantially parallel to the longitudinal axis; and wherein at least a pair of consecutive rows of the magnets are arranged such that the same magnetic poles of the magnets face each other and repel each other, thereby establishing regions of alternating magnetic polarity along the magnetic body in the running direction; and wherein the step of conveying the mixture on the conveyor belt adjacent to the conveyor bed includes conveying the mixture past at least some of the regions of alternating magnetic polarity of the magnetic body, thereby causing the particles to tumble along the conveyor belt.

12. The method according to claim 11, the method further comprising conveying the mixture past at least one elongated separator disposed between consecutive rows of the repelling magnets arranged in the magnet array.

13. The method according to any one of claims 11 and 12, wherein, The step of feeding at least a portion of the mixture onto the running conveyor belt includes magnetically attracting the portion of the mixture to the underside of the conveyor belt.

14. The method according to any one of claims 11 to 13, wherein The step of at least partially removing the particles from the conveyor belt includes a process selected from the group consisting of scraping the particles from the running conveyor belt; spraying the particles from the running conveyor belt; allowing the particles to fall from the underside of the running conveyor belt; and any combination of the above processes.

15. The method according to any one of claims 11 to 14, the method including adjusting the magnetic field applied through the conveyor belt by tilting the magnetic body relative to the running plane of the conveyor belt.

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