Improvements in stirred bead mills

Abstract

The invention relates to an agitated bead mill (1) comprising a substantially cylindrical grinding housing (2, 18) and a central agitating shaft (10) located in the grinding housing. The central agitation shaft is provided with axially spaced agitation elements along the central agitation shaft, preferably grinding discs (12). An exchangeable grinding element (80) is provided comprising an axial support structure (81) arranged to form an outer periphery of the grinding element adapted to fit in the grinding housing, and at least one opposing disc (14) arranged to project radially inward from the axial support structure (81) to an extent to separate two grinding regions in the axial direction, at least a portion of the counter disc (14) and / or the support structure (81) is provided with a castle-like structure (25A, 25B) while allowing the central agitation shaft to be located in the grinding housing.

Description

[0001] This application is a divisional application of the invention patent application entitled “Improvements in agitated bead mills”, with an international application date of January 26, 2017, an international application number of PCT / FI2017 / 050042, and a national application number of 201780084534.9. Technical Field

[0002] The present invention relates to improvements in stirred bead grinding mills for grinding mineral ore particles. Background Art

[0003] Agitated bead mills are commonly used in mineral processing to grind mineral ore particles into smaller sized particles to aid further downstream processing, such as separating valuable mineral particles from unwanted mineral gangue. For example, mineral ore particles with a diameter in the range of about 30 μm to 4000 μm can be ground into particles with a diameter of 5 μm to 100 μm.

[0004] Agitated bead mills typically have a fixed mill body or housing arranged vertically in the mill, and a drive shaft inside. The drive shaft has a plurality of agitating elements (such as grinding discs or rotors), so that rotation of the drive shaft also rotates the agitating elements, which in turn agitates suitable grinding media, and mineral ore particles in the form of a feed slurry pass through an agitated bed of such media. The resulting agitating action causes the mineral ore particles to be ground into smaller sized particles. However, the grinding discs and housing tend to be subject to high wear, especially when the mill is operated at high speeds by the action of harder grinding media acting on the grinding discs. Summary of the invention

[0005] One aspect of the present invention is a grinding element of an agitator bead mill for grinding mineral ore particles, the grinding element having a preferably cylindrical grinding shell and a central agitator shaft located in the grinding shell, wherein the grinding element comprises:

[0006] an axial support structure arranged to form the periphery of a grinding element capable of being fitted within a grinding shell, and

[0007] At least one opposing disk is arranged to protrude radially inwardly from the axial support structure to a certain extent to separate the two grinding areas in the axial direction while allowing the central agitation shaft to be located within the grinding shell, wherein at least a portion of the opposing disk and / or the axial support structure is provided with a castellation.

[0008] In one embodiment, the cross section of the grinding element is a hollow cylinder or an arc segment of a hollow cylinder, preferably an arc segment within a range of 20 to 180 degrees of the hollow cylinder, and more preferably a hollow semi-cylindrical cross section.

[0009] In one embodiment, the grinding element is sized to be mounted side-by-side with one or more other grinding elements in a radial plane within the grinding housing to form a grinding element assembly that is hollow cylindrical in cross-section.

[0010] In one embodiment, the axial length of the grinding element is smaller than the axial length of the cylindrical grinding shell, and the axial length of the grinding element is preferably smaller than the axial length of the grinding shell.

[0011] In one embodiment, the grinding element is sized to be stacked with one or more other grinding elements in an axial direction within a cylindrical grinding shell to form a grinding element assembly having a desired overall axial length.

[0012] In one embodiment, the central stirring shaft is provided with stirring elements spaced apart axially along the central stirring shaft, the stirring elements are preferably grinding discs, and at least one opposing disc is arranged to protrude radially inwardly from the axial support structure at an axial position offset from the axial position of the stirring elements of the stirring shaft.

[0013] In one embodiment, the axial support structure comprises an axial side wall defining an outer peripheral surface of the grinding element, and wherein the at least one opposing disk is arranged to protrude radially inwardly from an inner surface of the axial side wall.

[0014] In one embodiment, the axial support structure further comprises a plurality of spaced-apart wear protection elements arranged along an inner surface of an axial side wall of the axial support structure and protruding inwardly from the inner surface, and the plurality of wear protection elements arranged on the inner surface of the axial side wall protrude radially inwardly from the inner surface of the axial side wall.

[0015] In one embodiment, at least a portion of the protection elements comprises elongated protection elements extending parallel or nearly parallel along the inner surface of the axial side wall of the axial support structure.

[0016] In one embodiment, at least a portion of the elongated protection elements include two or more protection element segments connected in series in a row or other pattern.

[0017] In one embodiment, the axial profile and / or the side profile of the protection element comprises at least one or more of a block-like element, a fin and a flap.

[0018] In one embodiment, the plurality of protective elements are arranged to form a framework for a liner of a different material, the liner being arranged to be worn away during a grinding operation to expose the protective elements.

[0019] In one embodiment, the grinding element has a cage-like structure, wherein the axial support structure includes a plurality of spaced-apart elongated support members defining the outer periphery of the grinding element, and the at least one opposing disk is connected to the plurality of spaced-apart elongated support members of the axial support structure and is arranged to protrude radially inwardly from the plurality of spaced-apart elongated support members.

[0020] In one embodiment, at least a portion of the plurality of spaced apart elongated support members are arranged to extend parallel or nearly parallel to the axial direction, and / or to extend obliquely relative to the axial direction, and / or to extend non-linearly relative to the axial direction.

[0021] In one embodiment, at least a portion of the plurality of spaced apart elongated support members comprises curved support beams.

[0022] In one embodiment, the plurality of spaced apart elongate support members are arranged to form a framework for a liner of a different material, the liner being arranged to be worn away during a grinding operation to expose the spaced apart elongate support members.

[0023] In one embodiment, the at least one opposing disk comprises a castellated structure located on one side of the opposing disk.

[0024] In one embodiment, the at least one opposing disk comprises a castellated structure located on both sides of the opposing disk.

[0025] In one embodiment, the at least one opposing disk comprises a castellated structure located on both sides of the opposing disk.

[0026] In one embodiment, the castellated structure comprises spaced apart components at intervals of 10-60 degrees, preferably at intervals of 10-45 degrees, more preferably at intervals of 10-30 degrees, and most preferably at intervals of 10-20 degrees in the tangential direction.

[0027] In one embodiment, the height of the castellations in the axial direction is in the range of 0.5 to 3 times the axial thickness of the opposing disk, preferably about the same as the thickness of the opposing disk.

[0028] In one embodiment, the height of the castellations is in the range of 2 mm to 200 mm, preferably in the range of 5 mm to 150 mm, more preferably in the range of 10 mm to 100 mm.

[0029] In one embodiment, the ratio of the height of the castellations to the spacing of the castellations is in the range of 1 / 2 to 1 / 20, preferably in the range of 1 / 5 to 1 / 20, more preferably in the range of 1 / 8 to 1 / 12.

[0030] In one embodiment, the width of the castellations in the tangential direction is from 1 mm to about the thickness of the opposing disks, preferably from 5 mm to about the thickness of the opposing disks, more preferably about the thickness of the opposing disks.

[0031] In one embodiment, the total width of all castellations in the tangential direction is less than 0.25 to 0.35 times the tangential length of the grinding element.

[0032] In one embodiment, the orientation of the castellations is tilted in the range of 0 to 90 degrees, preferably in the range of 0 to 25 degrees, more preferably in the range of 0 to 10 degrees, relative to the radial direction of the opposing disk.

[0033] In one embodiment, the castellations extend across the opposing disks from the axial support structure to radially inner edges of the opposing disks.

[0034] In one embodiment, the castellated structure extends across a portion of the opposing disk between the axial support structure to the radially inner edge of the opposing disk, preferably across an inner portion of the opposing disk adjacent the inner edge of the opposing disk.

[0035] In one embodiment, the castellations extend beyond the radially inner edge of the opposing disk, preferably extend around the radially inner edge to connect to the castellations on the opposite side of the opposing disk.

[0036] In one embodiment, the castellations are located only on the radially inner edges of the opposing disks.

[0037] In one embodiment, the grinding element is a separate element that can be loosely mounted within the grinding housing.

[0038] In one embodiment, a grinding element can be connected to one or more other grinding elements to form a larger self-contained grinding element assembly that can be loosely mounted within a grinding housing.

[0039] In one embodiment, the grinding element is configured for use with grinding media having a diameter that can be selected from a range of approximately 0.5-20 mm depending on the F80 of the particulate material and the P80 of the ground particulate material in each specific grinding application.

[0040] In one embodiment, the grinding element is a refurbished grinding element.

[0041] Another aspect of the invention is a grinding element assembly comprising a grinding element according to any of the above embodiments.

[0042] Another aspect of the invention is an agitator bead mill comprising a substantially cylindrical grinding shell and a central agitator shaft located in the grinding shell, and at least one grinding element according to any of the above embodiments.

[0043] In one embodiment, the central stirring shaft is provided with stirring elements, preferably grinding discs, spaced axially along the central stirring shaft.

[0044] In one embodiment, the agitated bead mill comprises a vertical or horizontal disc mill.

[0045] Another aspect of the invention is the use of a grinding element according to any of the above embodiments for grinding mineral ore.

[0046] Another aspect of the invention uses a grinding element according to any of the above embodiments, wherein the diameter of the grinding media can be selected from the range of approximately 0.5-20 mm depending on the F80 of the particulate material and the P80 of the ground particulate material in each specific grinding application.

[0047] Another aspect of the invention is a method of refurbishing a grinding element according to any of the above embodiments, the method comprising:

[0048] removing the grinding elements from the agitator bead mill, and

[0049] Replace or rebuild worn castellations of grinding elements.

[0050] In one embodiment, the rebuilding includes constructing spare castellated structures to replace worn material.

[0051] In one embodiment, rebuilding includes building a castellated structure spare using one or more of the following techniques to replace the worn material: deposition welding, 3D printing, adding rubber or polymer to the worn area.

[0052] In one embodiment, replacing includes attaching a new castellated structure to the grinding element by one or more of bolting, riveting, welding, gluing, and bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In the following, the invention will be described in more detail by means of exemplary embodiments with reference to the accompanying drawings, in which:

[0054] Figure 1 is a perspective view of an exemplary grinding machine suitable for including a grinding element according to one embodiment of the present invention;

[0055] Figure 2 yes Figure 1 A side view of a grinding machine;

[0056] Figure 3 yes Figure 1 A front view of a grinding machine;

[0057] Figure 4 is used for Figure 1 a cut-away side view of a portion of an exemplary grinder body in a grinder of;

[0058] Figure 5A is a perspective view of an exemplary flat abrasive disc;

[0059] Figure 5B is a perspective view of an exemplary opposing disk;

[0060] Figure 6 is a perspective view of an exemplary castellated grinding disc;

[0061] Figure 7 is a front view of an exemplary castellated grinding element located on an opposing disk;

[0062] Figure 8 is a perspective view of an exemplary castellated grinding element having a hollow semi-cylindrical cross-section;

[0063] Figures 9A-9H showing cross-sectional side views of various exemplary grinding elements;

[0064] Figures 10A-10C shows perspective views of exemplary castellated grinding elements having different types of cross-sections;

[0065] Figures 11A-11B shows a perspective view showing stacked exemplary castellated grinding elements;

[0066] Fig. 12A and 12B An exemplary installation of a grinding element according to an exemplary embodiment in a grinding machine is shown;

[0067] Fig.13 is a side view of an exemplary grinding element having a cage-like structure; and

[0068] Fig.14 is a cross-sectional side view of a castellated structural element embedded in a coating of different lossy materials. DETAILED DESCRIPTION

[0069] The invention will now be described with reference to the following examples, which are to be considered in all respects as illustrative and non-restrictive.

[0070] It will also be appreciated that embodiments of the present invention can be readily applied to various types of mineral ores having various particle sizes and particle size distributions. The particle sizes of feed and discharge are usually measured. Thus, the particle size of a slurry (e.g., granular material and slurrying liquid) at the feed inlet is usually described by its F80, which refers to 80% of the feed particles (by mass) passing through a specified screen size. For example, F80=1000 μm means that 80% of the total mass of the particles fed will pass through a 1000 μm sieve. An alternative size description is F100, which refers to 100% of the feed particles passing through a specified screen size. Similarly, it will be understood by those skilled in the art that P80 refers to 80% of the mass of the discharged particles passing through a specified screen size. For example, P80=60 μm means that 80% of the mass of the discharged particles will pass through a 60 μm sieve. Embodiments of the present invention have been primarily developed to process particle sizes in the range of F80 = 30 μm to F80 = 4000 μm, in particular in the range of F80 = 80 μm to F80 = 1000 μm, for feed granular material, and in the range of P80 = 0.1 μm to P80 = 800 μm, in particular in the range of P80 = 1 μm to P80 = 400 μm for ground discharge product. Thus, for mineral particles having a wide particle size distribution within the above-mentioned F80 and P80 ranges, embodiments of the present invention allow the grinder 1 to process a wide range of particle sizes to produce very fine particle sizes down to P80 = 1 μm. Thus, embodiments of the present invention can be readily applied to many different types of granular materials and are not limited to specific mineral ore types, but may include iron, quartz, copper, nickel, zinc, lead, gold, silver and platinum. Other granular materials that can be processed using embodiments of the present invention include concrete, cement, recyclable materials (such as glass, ceramics, electronic devices and metals), food, paint pigments, abrasives and pharmaceutical substances. In these other applications, embodiments of the present invention are used to reduce the size of granular materials using a grinding process.

[0071] It will also be appreciated that embodiments of the present invention can be readily applied to various types of agitator bead mills having a fixed grinding housing and a central agitator shaft having agitator elements, preferably grinding discs, axially spaced along the central agitator shaft. Examples of suitable agitator mills are described in the applicant's co-pending PCT patent application PCT / FI2016 / 050545, which is incorporated herein by reference. Hereinafter, examples of the structure and operation of suitable agitator mills, particularly disc mills, are shown to make it easier to understand embodiments of the present invention, but it is not intended to limit the application of the present invention to these exemplary mills.

[0072] In the various figures, corresponding features in the same embodiment or common features of different embodiments have been given the same reference numerals. Figure 1 5, an agitated bead mill 1 for grinding a slurry having a particulate material may include a mill body 2 and a drive mechanism 4 for providing an agitating action in the mill body 2 by rotating a drive shaft 11 of the mill body 2 about a longitudinal axis 6. The mill body 2 and the drive mechanism 4 may be mounted on a frame structure, such as a base frame 3 and a drive frame 5, respectively, in the exemplary embodiment shown. In the example shown, the mill body 2 may include a mounting assembly 9 for mounting the mill body to the base frame 3 and operatively aligning the mill body with the drive mechanism 4. In an embodiment, the mill may be a fine grinder and is referred to as a high intensity grinder, in which the rotational action causes an intense grinding of the slurry particles by the grinding media. In order to achieve fine grinding, the mill may have a relatively high energy consumption, such as in the range of 5 kWhr / t to 100 kWhr / t (kilowatt hours per ton). The power density of the mill kW / m 3 It can also be relatively high, for example up to 100-300 kW / m 3 or higher.

[0073] The feed slurry comprising mineral ore particles can be fed into the mill body 2 through the bottom inlet 7, which is shown as a central inlet in this example. The mill body 2 can be partially filled (e.g., filled with about 2 / 3) grinding media (such as beads). Before adding the feed slurry (e.g., granular material and slurrying liquid) and operating the mill 1, the grinding media can also be first added to the mill body 2 through the outlet 8, or added to the top of the mill via a separate inlet. In operation, the mill body 2 or the stirring mechanism 10 in the mill body 2 is rotated around the axis 6 by the drive mechanism 4 to rotate or stir the feed slurry and the grinding media together, thereby providing a relative movement of the grinding media and the slurry of the granular material at a desired speed in the grinding chamber, and causing the feed slurry particles to be crushed or ground against the grinding media or between the grinding media, thereby causing comminution due to friction between the grinding media. For example, the tip speed of the stirring mechanism can be in the range of 4-12m / s. Subsequently, the ground product can be discharged through the top outlet 8. The grinding media may typically include ceramic or steel beads having a diameter between 0.5 mm and 20 mm. In other embodiments, the size of the grinding media may be varied as desired. For example, the diameter of the grinding media may be 30 or 50 times the diameter of the slurry particles, which may be measured by reference to F80 or F100. For example, the diameter of the grinding medium can be selected from the range of approximately 0.5-20 mm depending on the F80 of the particulate material and the P80 of the ground particulate material in each specific grinding application, preferably from the range of 0.5-1.5 mm for an F80 of 70 μm or less and a P80 of 20 μm or less, preferably from the range of 1-3 mm for an F80 of 50-100 μm and a P80 of 20-60 μm, preferably from the range of 3-6 mm for an F80 of 100-300 μm and a P80 of 50-100 μm, and preferably from the range of 6-20 mm for an F80 of 300-4000 μm and a P80 of 80-300 μm.

[0074] refer to Figure 4 In the exemplary embodiment shown, the housing 18 is arranged vertically in the grinder and has a bottom inlet 7 and a top outlet 8. It will be appreciated that in other embodiments, the grinder body 2 can be arranged in the grinder 1 at an angle or tilt. In some embodiments, the housing 18 can be arranged horizontally across the grinder. Likewise, in other embodiments, the inlet 7 and outlet 8 can be provided at other locations of the housing other than the bottom and top, respectively.

[0075] refer to Figure 4, an exemplary embodiment is shown in which the grinder body 2 may include a generally cylindrical drum or housing 18 defining an inner cavity or grinding chamber 15, and a rotating agitator assembly 10 located in the housing 18. The term "cylindrical" as used herein should be understood to generally refer to any cylindrical structure having an annular or circular cross-section. Although in the exemplary embodiment shown, the grinder body may have a generally cylindrical shape, it should be appreciated that in other embodiments, the grinder body or housing 18 may take other cross-sectional shapes (such as rectangular, square, elliptical or oval), or any other regular or irregular polygon (such as a hexagon) to define the grinding chamber 15. The agitator assembly may include one or more drive shafts 11, on each of which a plurality of agitators 12 described in more detail below may be mounted. The one or more drive shafts may be coaxial with the grinder body 2 (e.g., as shown in the exemplary embodiment) or non-coaxial. As shown in the exemplary embodiment, the one or more drive shafts may be parallel to the longitudinal axis 6 of the grinder body 2, or the drive shafts may be inclined or at an angle relative to the axis of the grinder body. The agitation device 12 may be coaxial with the axis of the drive shaft, as shown in the exemplary embodiment, or they may not be coaxial. In the exemplary embodiment, the agitation effect is caused by the rotating agitation device 12 mounted on the drive shaft 11. The agitation device assembly 10 is in the form of an impeller or rotor, but is also referred to as a drive shaft assembly. Thus, with reference to this embodiment, the agitation device assembly will be referred to as a grinder rotor hereinafter.

[0076] In an embodiment, the agitation device 12 in the grinder rotor 10 may include a plurality of coaxial or non-coaxial grinding discs 12 spaced apart along the length of the drive shaft 11 . Figure 5AAn example of a grinding disc 12 is shown in FIG. In an exemplary embodiment, the grinding disc 12 may include a flat disc body 20, which may be connected to a mounting ring 21 via arms 22 (commonly referred to as spokes), and the mounting ring 21 is used to mount the grinding disc 12 to the drive shaft 11 of the agitator assembly 10. Although the agitator is an annular disc in the exemplary embodiment, it should be appreciated that in other embodiments the agitator may take other planar forms, such as rectangular, square, oval or elliptical, annular, and any other regular or irregular polygonal shape. Those skilled in the art will appreciate that for industrial functions, the annular disc size may range from 400 mm in diameter to 2500 mm in diameter. However, the present invention is equally applicable to fine grinding discs of any size. Similarly, the agitator 12 may have other surfaces other than two opposing surfaces, such as any number of surfaces having the same or different shapes. For example, the agitator may have an inclined or angled surface, a curved surface, a wavy surface, a serrated surface, an irregular surface, or any other regular or irregular shape. In an embodiment, the grinding disc may have a through hole, an opening, an interruption, or a cutout. For ease of reference, the agitation device 12 in this embodiment will be referred to as a grinding disc hereinafter. However, embodiments of the present invention are not limited to any particular structure or design of the agitation device assembly or agitation device. For example, the agitation assembly may alternatively include radial posts spaced apart along the drive shaft. As another example, the agitation assembly may include an auger.

[0077] There may also be a plurality of stationary planar annular shelves or counter plates 14 located on the inner side wall 13 of the grinder housing 18 and between each rotating agitator or grinding plate 12 . Figure 5B An example of an opposing disk 14 is shown in FIG. A planar annular shelf or opposing disk 14 may extend or protrude into a cavity 15 located between the agitating means or grinding disks 12. The shelf 14 tends to divide the inner cavity 15 into independent sub-cavities 17 interconnected by openings 16 defined between the shelf 14 and the drive shaft 11. Depending on the application, there may be any number of groups of agitating means 12 and shelves 14, such as rotating disks and fixed disks. For example, there may be up to several dozen groups, but typically 5-20 groups.

[0078] In operation, the drive mechanism 4 rotates the drive shaft 11 of the agitator assembly 10, which rotates the grinding disc 12, which in turn provides a rotational motion at a desired speed to the grinding media and slurry of particulate material in the grinding chamber 15 of the mill body 2 (as shown by the transverse arrows in the figure). The rotational motion causes the feed slurry particles to be ground against and between the harder grinding media, thereby releasing valuable mineral particles and reducing their size for further downstream processing after discharge through the outlet 8. The slurry flow is transmitted upwardly through the opening 16 to the sub-chamber 17, passing the rotating disc 12, and then entering the next sub-chamber 17 through the next opening 16. The free space within each sub-chamber 17 and around the rotating grinding disc 12 can be regarded as a classification station, where the coarser particles move towards the inner wall of the housing 18, while the finer particles move upwardly through the opening 16 more quickly. Due to the vertical arrangement of the mill, classification is always carried out simultaneously throughout the grinding process, where larger particles stay longer at the periphery, while smaller particles move upwardly.

[0079] In other words, in an exemplary vertical agitated bead mill, the feed slurry is fed from below, where the ore particles are gradually ground smaller by the moving grinding media beads before exiting from the top of the mill. The grinding media beads are much larger (e.g., tens of times larger) than the ore particles, which is necessary for grinding and also keeps the grinding media beads inside the mill because they can settle faster than the upward flow rate of the feed slurry. However, the size of the mill can be designed so that the grinding media beads are partially liquefied by the upward flow of the feed slurry. The electrical power required to drive the shaft is sensitive to the feed flow rate, i.e., at higher flow rates, the grinding media beads are slightly lifted and exert less resistance on the grinding disc. In a horizontal agitated bead mill, a centrifugal separator can be provided at the end of the mill to keep the beads and coarser particles in the mill.

[0080] In an agitated media mill, the shear forces are considerable. Ideally, the mill would not wear, but in practice, liner and disc wear is inevitable even in well designed and constructed equipment. Accelerated wear of mill components results in a very short operating life, requiring more frequent replacement than is desirable. Frequent replacement of mill components also increases the length of downtime, reduces mill efficiency, and increases maintenance costs.

[0081] Uneven wear of the grinding discs has been observed in agitator mills, where wear occurs faster for the lower grinding disc (located at the feed end) than for the upper grinding disc (located at the discharge end). Preferably, the grinding discs will continue to function for several months and wear more evenly, so that the replacement period of the grinding discs is simultaneous. One reason for uneven wear may be that the grinding media beads are only partially liquefied, which means that only a portion of the weight of the grinding media beads is carried by the upward flow of the feed slurry. The remaining gravity is carried downward by the stacked bed of grinding media beads, so that gravity is highest at the bottom of the mill. This increases the forces on the mill housing and the grinding discs, so the mill housing and grinding discs are subject to higher wear rates towards the bottom of the mill. Another reason for uneven wear may be the introduction of coarse feed particles into the bottom of the mill, which may also increase the wear rate at the base of the mill. Similar uneven wear also occurs in horizontal agitator mills, which also wear faster at the feed end.

[0082] In the applicant's co-pending PCT patent application PCT / FI2016 / 050545 (which patent application is incorporated herein by reference), such an embodiment is recommended in which a protective castellated structure can be provided on the agitator or grinding disk 12 to capture the media layer and form the media layer on the rotating disk so as to minimize the differential speed between the media and the rotating disk, thereby reducing wear. Figure 6 , an exemplary embodiment of a grinding disc 12 provided with a castellated structure 25 is shown. In this exemplary embodiment, the castellated structure may include a protective element 25, which may be disposed adjacent to the outer edge of the disc body 20 to extend outwardly from the disc body 20. In an exemplary embodiment, a mounting hub 21 may be connected to the disc body 20 via arms 22 (commonly referred to as spokes) for mounting each grinding disc 12 to the drive shaft 11 of the agitator assembly 11. The protective element 25 in this embodiment is in the form of a block or block-like element, which is integrally formed with the disc body 20 and is disposed so that each opposing side and one end of the block may protrude outwardly from the planar surface and the outer edge of the disc body 20. Thus, each block 25 may extend substantially orthogonally relative to the opposing planar surface via its opposing sides, and extend radially outwardly from the outer edge via its ends. Alternatively, the protective element 25 may be in the form of a U-shaped block mounted to the disc body 20 such that opposite sides and one end of each block 25 extend or protrude outwardly from the planar surface and outer edge of the disc body, respectively. It will be appreciated that the protective element 25 may be in any number of forms to form an area around each grinding disc 12. Examples of other forms or shapes of protective elements are disclosed in the applicant's co-pending PCT patent application PCT / FI2016 / 050545, which is incorporated herein by reference.

[0083] In the applicant's co-pending PCT patent application PCT / FI2016 / 050545 (which is incorporated herein by reference), an embodiment is proposed in which a protective castellated structure 25 can be provided on the shelf 14 to further minimize wear of the shelf and the inner sidewalls, such as Figure 7 as shown in .

[0084] Despite these improvements, there remains a need to reduce wear on components of a grinding machine, reduce the time and effort required to replace components, reduce downtime, and / or reduce maintenance costs.

[0085] According to one aspect of the present invention, a novel grinding element for an agitator grinding mill is provided. The grinding element comprises an axial support structure arranged to form an outer periphery of the grinding element adapted to be fitted in a grinding shell. The grinding element further comprises at least one opposing disc arranged to protrude radially inwardly from the axial support structure to such an extent that the grinding zone is divided into two grinding zones in the axial direction of the grinding shell, while allowing a central agitator shaft to be arranged in the grinding shell. At least part of the opposing discs and / or the support structure is configured with a castellated structure.

[0086] In the embodiment, the cross section of the grinding element can be any arc segment of the hollow cylinder, and the cross section is preferably an arc segment within the range of 20 to 180 degrees of the hollow cylinder, and the cross section is more preferably a hollow semi-cylinder.

[0087] Figure 8 , an exemplary grinding element 80 is shown in the figure as a hollow semi-cylindrical cross-section. In the example shown, the grinding element 80 includes an axial support structure in the form of an axial side wall 81, which defines the outer peripheral surface of the grinding element 80. The outer peripheral surface of the grinding element 80 can be arranged to fit tightly or loosely against the inner surface of the shell to form a replaceable protective sub-shell or liner that prevents wear of the actual shell 18. The grinding element 80 also includes an annular opposing disk 14, which is arranged to protrude radially inwardly from the inner surface of the axial side wall 81. In an embodiment, the opposing disk 14 is arranged to protrude radially inwardly from the axial support structure at an axial position within the grinding shell 18 that is offset from the axial position of the grinding disk 12 of the agitator shaft.

[0088] exist Figure 8 In the exemplary grinding element 80 shown in FIG. 8 , the axial side wall 81 and the opposing disk 14 are provided with castellations 25A and 25B, respectively. Fig.9A A cross-sectional side view of grinding element 81 is shown in FIG. Castellations 25A and 25B reduce wear of sidewall 80 and opposing disk 14, thereby extending the life of grinding element 80. Fig.9A , 9COther examples of grinding elements 80 having castellations 25A and 25B on both the axial sidewall 81 and the opposing disk 14 are shown in FIGS. 9A and 9D.

[0089] In an embodiment, Figure 9H As shown in the example in FIG. 8 , the castellated structure 25A may be present only on the side wall 81 .

[0090] In other embodiments, Fig. 9B , 9E As shown in the examples in 9F and 9G, the castellated structure 25B may be provided only on the opposing disk 14.

[0091] The castellated structure of the axial sidewall 81 may include a plurality of spaced apart wear protection elements 25A disposed on the inner surface of the axial sidewall 81 in a manner protruding radially inwardly from the inner surface of the axial sidewall 81. The protection elements 25A may be elongated protection elements extending parallel to the axis of the grinding element.

[0092] like Figure 8 , 9A , 9B, 9C, 9E, 9F and 9G, the opposing disk 14 may include a castellated structure located on one or both sides of the opposing disk 14. In some embodiments, as Figure 8 , 9A , 9B, 9C and 9E, the castle-like structure 25B may be located on one or both sides of the opposing disk 14, but not on the radial inner edge of the opposing disk 14. In some embodiments, as Fig.9D , 9F As shown in the example of FIG. 9G , the castellated structure 25B may be located on one or both sides of the opposing disk 14 , and also located on the radially inner edge of the opposing disk 14 .

[0093] In embodiments, the shelf or counter tray 14 may have holes, interruptions or cutouts to enhance sludge flow.

[0094] In an embodiment, Fig.9A and 9B As shown, the castellations 25B may extend across the radial width of the opposing disk 14 from the inner sidewall 81 to the radially inner edge of the opposing disk 14 .

[0095] In some embodiments, Fig. 9C , 9D , 9F and 9G, the castellated structure 25B may extend on one or both sides of the opposing disk 14 over a portion of the radial width of the opposing disk 14, preferably across an inner portion of the opposing disk 14 near the inner edge of the opposing disk. Fig.9DAs shown in , there may be a castellated structure 25B on the radial inner edge of the opposing disk 14 or at the tip of the opposing disk. In some embodiments, the castellated structure 25B may extend beyond the radial inner edge of the opposing disk 14, preferably extending around the radial inner edge to connect to the castellated structure 25B located on the opposite side of the opposing disk 14.

[0096] Fig. 10A An exemplary grinding element 80 having a cross-section of 1 / 3 of a hollow cylinder (a 120 degree segment of a cylinder) is shown in FIG.

[0097] Fig. 10B An exemplary grinding element 80 having a cross-section of ¼ of a hollow cylinder (a 90 degree segment of a cylinder) is shown in FIG.

[0098] Fig. 10C An exemplary grinding element 80 having a full hollow cylinder (360 degrees) cross section is shown in FIG. In this case, the radius of the central opening 16 of the grinding element 80 must be greater than the outer diameter of the grinding disc 12 to allow the agitator shaft 11 and the grinding disc 12 to pass through the opening 16 during installation.

[0099] In embodiments where the cross-section of the grinding element may be an arcuate segment of a hollow cylinder, the grinding element 80 is sized to be mounted side-by-side with one or more other grinding elements 80 in a radial plane within the grinding shell 18 to form a grinding element assembly having a hollow cylindrical cross-section. For example, a pair of grinding elements 80 having a semi-cylindrical cross-section (180 degree segment) may be mounted side-by-side to obtain a complete hollow cylinder, similar to Fig. 10C Similarly, three 120-degree grinding elements or four 90-degree grinding elements can be arranged side by side to form a grinding element assembly with a hollow cylindrical cross section. In an embodiment, the grinding element 80 may include a device for connecting to one or more other grinding elements. For example, such a connecting device may include one or more of a clip, a flange, and a bolt connection.

[0100] In an embodiment, the grinding element 80 may be a separate element adapted to be loosely mounted within the grinding housing 18 .

[0101] In an embodiment, the axial length of the grinding element 80 is substantially equal to or a multiple of the distance between the axially spaced grinding discs 12 of the central agitation shaft 11. Typically, the axial length of the grinding element is less than the axial length of the cylindrical grinding shell.

[0102] In an embodiment, the grinding element 80 is sized to be stacked with one or more other grinding elements 80 in the axial direction within the cylindrical grinding shell 18 to form a grinding element assembly 800 having a desired overall axial length. Fig.11A and11B In the example shown in , four semi-cylindrical grinding elements 80 are stacked on top of each other to form a longer grinding element assembly 800. Similarly, Fig. 10A , 10A and the exemplary grinding element 80 shown in 10C, or other types of grinding elements.

[0103] In an embodiment, the grinding element assembly 800 may be assembled or manufactured before installing the grinding element assembly in the grinding machine housing 18. In an embodiment, two or more grinding element assemblies 800 may be formed first, and then the grinding element assemblies 800 may be installed and stacked in the grinding machine grinding housing 18.

[0104] In an embodiment, a single grinding element 80 may include two or more opposing disks 14 in the axial direction. Such a single grinding element with multiple opposing disks may be manufactured in various alternative ways (e.g., welding or casting). For example, a single grinding element 80 with four opposing disks 14 in the axial direction may be similar to Fig. 11B The grinding element assembly 800 shown in FIG.

[0105] In an embodiment, grinding element assembly 800 is a separate element adapted to be loosely mounted within grinding housing 18 .

[0106] Fig. 12A and 12BThe grinding element 80 according to the exemplary embodiment is shown to be exemplarily installed in the grinder 1, more specifically in the grinder housing 18 of the grinder body. In the example shown, the grinder body 2 can be axially (e.g. vertically in a vertical grinder, horizontally in a horizontal grinder) divided into two halves or three or more segments that can be removed along the center. For example, the two halves of the grinder body can be axially (vertically) flanged so that the two halves can be separated. For example, the two halves of the grinder body 2 can be hinged together so that the two housing halves can be rotated and separated when the flange bolts are removed, etc. After exposing the interior of the housing 18, the semi-cylindrical grinding element 80 can be installed or assembled to the two halves of the grinder body 2 in the housing 18. Moreover, if necessary, the grinding disc 12 can be easily replaced at this time. In the example shown, 9 semi-cylindrical grinding elements 80 are stacked in each half of the grinder body 2. Thus, a semi-cylindrical grinding element assembly 800 is provided in each half of the grinder body 2. The outer wall 81 of the grinding element 80 can be arranged to be tightly or loosely mounted against the inner surface of the housing to form a replaceable protective sub-housing or lining that prevents the actual housing 18 from being worn. The grinding element 80 or the grinding element assembly 800 can be connected to the housing 18 by appropriate connecting means, or they can be plug-in units. The half of the grinder body 2 including the grinding element 80 or the grinding element assembly 800 can be connected together around the stirring shaft 11 and the grinding disc 12 at this time to form a cylindrical drum 2 containing a sub-housing in the form of a cylindrical grinding element assembly. The actual housing 18 is completely protected from wear. The worn grinding element 80 can be easily replaced by the reverse procedure: the grinder body 2 is divided into each half, the worn grinding element 80 is selectively replaced, and the grinder body is reassembled. In the case of uneven wear of the grinding element 80, each worn grinding element 80 can be replaced, and the unworn element 80 can not be replaced, which reduces maintenance work and costs and spare parts costs. Since virtually only the grinding elements 80 will wear, the life of the grinder body will be significantly extended.

[0107] Since the castellations 25A and / or 25B on the grinding element 80 are usually worn before the sidewall 81 and the opposing disk 14, the worn grinding element 80 can be reused by repairing the castellations 25A and / or 25B. New castellations 25A and / or 25B can be provided by various means (for example, including 3D printing). Alternatively, the worn element can be refurbished by welding to construct the worn area (steel liner), and the worn castellations and / or opposing disks can be replaced by bolting / welding / riveting, etc. A polymer liner can be constructed by adding new polymer. Alternatively, the worn area can be repaired by attaching a harder material (such as ceramic or carbonized tile) by gluing, bonding, bolting or any other attachment method.

[0108] In an exemplary embodiment of the present invention, a castellated structure is realized by a block-shaped element as a preferred form. The castellated structure is not limited to block-shaped elements, but the castellated structure can be realized by any form of protrusion extending from the surface of the opposing disk 14 or the side wall 81. In an embodiment, the axial profile and / or side profile of the castellated structure may include at least one or more of the following: a protrusion, an elongated body, a block-shaped element, a flange, a toothed portion, a planar element, a wing, a blade, a fin, a plate, a bar, a column, a rod, a channel-shaped element, a V-shaped element, a U-shaped element, a ramp-shaped element, and a wedge-shaped element. Another embodiment has an annular shelf 14 with an angle or tilt, rather than being orthogonal to the side wall 81.

[0109] In an embodiment, the size of the castle-like structure can be designed to protrude from the side wall and / or the opposing disk 14 to a certain height that is at least half the size of the grinding media, preferably at least one and a half times the size of the grinding media, and more preferably at least three times the size of the grinding media.

[0110] In an embodiment, the inward height of the castellations may be in the range of 2 mm to 200 mm, preferably in the range of 5 mm to 150 mm, more preferably in the range of 10-100 mm, depending on the size of the grinder or disc.

[0111] The elements of the castellations may be spaced apart from each other in the circumferential direction or in the direction of the rotational motion of the grinding media and the slurry of the granular material. In an embodiment, the spaced apart castellations are at intervals α of 10-60 degrees, preferably at intervals of 10-45 degrees, more preferably at intervals of 10-30 degrees, even more preferably at intervals of 10-20 degrees in the direction of the rotational motion of the grinding media and the slurry of the granular material. In an embodiment, the ratio of the height of the castellations to the spacing between adjacent castellations may be in the range of 1 / 2 to 1 / 20, preferably in the range of 1 / 5 to 1 / 20, more preferably in the range of 1 / 8 to 1 / 12.

[0112] In an embodiment, the castellated elements 25A may include elongated castellated elements that extend longitudinally between the shelves or opposing plates 14 on the side walls 81 of the grinding element 80. By "longitudinally" it is meant that the elongated guard elements may extend in a direction transverse to or at an angle to the direction of rotation of the grinding media and slurry of particulate material, or in a direction parallel to or at an angle to the axial direction 6 of the mill body.

[0113] In one embodiment, the elongated castellated structural elements 25A may extend longitudinally generally parallel to the axis of the grinder housing 18 between the shelves or counter trays 14 on the side walls 81 .

[0114] In another embodiment, the elongated castellated structural elements 25A may extend longitudinally on the sidewall 81 of the grinding element 80 generally parallel to the axis of the grinder housing 18 .

[0115] In a vertical grinder, the castellated elements 25A may be vertical elements and in a horizontal grinder a horizontal element. In an embodiment, the elongated castellated elements 25A extending longitudinally between the shelves or opposing plates 14 on the side walls 81 of the grinding element 80 may be inclined or angled with respect to the axial direction 6 of the grinder housing 18.

[0116] In one embodiment, the elongated castellated structural elements 25A extending longitudinally between the shelves or counter-discs 14 on the side walls 81 of the grinding element 80 may be arranged along a helical path that follows the axial direction 6 about the grinder housing.

[0117] In other embodiments, any other alternative longitudinal shape of the elongated castellated structural elements 25A may be employed.

[0118] In one embodiment, the elongated castellated structural elements 25A extending longitudinally between the shelves or opposing disks 14 on the side walls 81 of the grinding element 80 only traverse a portion of the distance between the shelves or opposing disks 14.

[0119] In one embodiment, the elongated castellations 25A extending longitudinally between the shelves or opposing disks 14 on the sidewalls 81 of the grinding element 80 may each include two or more castellations segments connected in series in a row or other pattern. The castellations segments may be block-shaped segments or rod-shaped segments, or they may have any other shape, such as hexagonal, elliptical, or any other polygonal shape, depending on the application.

[0120] In embodiments, the castellations 25A and 25B may have holes, interruptions or cutouts to allow mud to flow around the castellations.

[0121] In an embodiment of the present invention, the grinding element 80 may have a cage-like structure with an axial support structure, the axial support structure including a plurality of spaced apart elongated support members 25A defining the outer periphery of the grinding element 80, and at least one opposing disk 14 is connected to the plurality of spaced apart elongated support members 25A of the axial support structure and is arranged to protrude radially inwardly from the plurality of spaced apart elongated support members 25A, as shown in the example shown in FIG. Fig.13 In the example of the embodiment, the cross section of the grinding element 80 is a hollow cylinder having three annular castellated shelves or opposed plates 14. In addition to the omission of the side wall 81, the exemplary grinding element 80 can be similar to the three Figure 8 In other words, the parts 25A of the axial support structure are connected to each other by the shelf 14, thereby obtaining a cage-like structure. Similarly, the cage-like grinding element 80 can be realized by omitting the side wall 81 of the other embodiments described above. In addition, the various embodiments and features described above can also be applied to the embodiments with a cage-like structure. The spaced-apart elongated support parts 25A can also serve as a castle-like structure of the shell 18 of the grinder body. The cage-like grinding element 80 does not protect the shell 18 as well as the grinding element 80 with the side wall 81, but the cage-like grinding element 80 is lighter, easier to handle, and has a lower production cost.

[0122] refer to Fig.14 In another embodiment, one or more of the castellations 25A and 25B may serve as a framework for coating a different material 40. The coating of the different material 40 may be arranged to form a loss protection layer on the inner surface of the sidewall 81 and the castellations 25A and 25B. The loss protection material 40 may be used to provide an integral grinding element 80 that is easier to replace because the material 40 may make the grinding element 80 harder. This is particularly advantageous in embodiments having a cage-like structure. The loss protection material 40 may also extend the useful life of the castellations 25A and 25B and the sidewall 81, although the loss protection material 40 may be arranged to wear out within a very short period of time after installation and the start of the grinding operation. For example, the different material may be polyurethane. For example, a grinding element 80 having castellations 25A and 25B coated with or embedded in a loss material 40 may appear to have a flat inner surface when installed, and acquire a final shape during operation after the loss material 40 has worn away.

[0123] Although the embodiments have been described with reference to a vertically disposed grinder body and grinder, the invention may also be used in other grinder types, such as grinders having a horizontally disposed or angled grinder body.

[0124] Furthermore, while the embodiments have been described with reference to a grinder type using a stationary grinder housing 18 or grinder body 2 having a rotating agitation shaft 11 and agitation elements 12, implementation of the invention may also be applied to grinder types using a rotating grinder housing 18 or grinder body 2 having a stationary agitation shaft 11 and stationary agitation elements 12 disposed in a grinding chamber 15. The axis of rotation of the housing 18 or grinder body 2 may or may not be coaxial with the grinder body 2. The axis of rotation may be parallel to the longitudinal axis 6 of the grinder body 2, or the axis of rotation may be inclined or at an angle to the axis of the grinder body.

[0125] In addition, embodiments of the present invention may also be applied to a grinder type that uses a rotating stirring shaft 11 and stirring elements 12 disposed in a grinding chamber 15 and a rotating grinder housing 18 or grinder body 2. The rotation axis of the housing 18 or grinder body 2 may be coaxial or non-coaxial with the rotation axis of the stirring shaft 11. The rotation axis of the housing 18 or grinder body 2 may be parallel to the rotation axis of the stirring shaft 11, or the rotation axis of the housing 18 or grinder body 2 may be inclined or at a certain angle to the rotation axis of the stirring shaft 11.

[0126] It will also be appreciated that any of the features in the exemplary embodiments of the present invention may be combined together, rather than necessarily being applied independently of one another. For example, different types of grinding elements 80 may be used in the same grinder housing. Some grinding elements 80 may have castellations 25A and / or 25B, while other grinding elements 80 may not have castellations 25A and / or 25B. Shear forces and wear are typically greatest at the bottom portion of the housing, and thus the castellations 25A and / or 25B may preferably be disposed at least at the bottom portion of the housing.

[0127] A person skilled in the art may easily make similar combinations of two or more features of the above-described embodiments or preferred forms of the present invention.

[0128] The grinding element according to an embodiment of the present invention can form a protective layer or area of ​​the grinding medium on the wearable part, which reduces the amount of wear and thus prolongs the operating life of the parts of the grinding machine, reduces maintenance time and cost, and improves the efficiency of the grinding machine. The protective layer or area produced by the castle-like structure can also promote the slurry particles to contact the grinding medium, and also improve the grinding efficiency. Thus, the grinding machine can operate more efficiently, consuming parts such as grinding discs at a lower rate while grinding at a faster rate. Moreover, it can be easily refurbished in an existing fine grinding machine. In all these aspects, the present invention presents a significant practical and commercial improvement over the prior art.

[0129] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A grinding element for an agitator bead mill for grinding mineral ore particles, the grinding element having a preferably cylindrical grinding shell and a central agitator shaft located in the grinding shell, wherein the grinding element comprises: an axial support structure arranged to form the periphery of a grinding element capable of being fitted into a cylindrical grinding shell of an agitator bead mill, and At least one opposing disk is arranged to protrude radially inwardly from the axial support structure to a certain extent to separate two grinding areas in the axial direction within the cylindrical grinding shell, while allowing the central agitation shaft to be installed in the grinding shell, wherein the at least one opposing disk and / or at least a portion of the axial support structure is provided with a protective castle-like structure, the castle-like structure is configured to capture grinding beads on the axial support structure and / or the at least one opposing disk and form a protective layer or area of ​​the grinding beads, thereby reducing wear when grinding mineral ore particles.

2. The grinding element according to claim 1, wherein The cross section of the grinding element is a hollow cylinder or an arc segment of a hollow cylinder, the cross section is preferably an arc segment within a range of 20 to 180 degrees of the hollow cylinder, and the cross section is more preferably a hollow semi-cylindrical shape; or Preferably, wherein the grinding element is dimensioned to be mounted side by side with one or more other grinding elements in a radial plane within the grinding housing to form a grinding element assembly that is hollow cylindrical in cross section; or Preferably, wherein the axial length of the grinding element is smaller than the axial length of the cylindrical grinding shell, the axial length of the grinding element is preferably smaller than the axial length of the grinding shell; or Preferably, the grinding element is sized to be stacked with one or more other grinding elements in an axial direction within a cylindrical grinding shell to form a grinding element assembly having a desired overall axial length; or Preferably, wherein the central stirring shaft is provided with stirring elements axially spaced apart along the central stirring shaft, the stirring elements preferably being grinding discs, and wherein at least one counter-disc is arranged to project radially inwardly from the axial support structure at an axial position offset from the axial position of the stirring elements of the stirring shaft; or Preferably, wherein the axial support structure comprises an axial side wall defining an outer peripheral surface of the grinding element, and wherein the at least one opposing disk is arranged to protrude radially inwardly from an inner surface of the axial side wall; or Preferably, the axial support structure further comprises a plurality of spaced-apart wear protection elements arranged along an inner surface of an axial side wall of the axial support structure and protruding inwardly from the inner surface, and the plurality of wear protection elements arranged on the inner surface of the axial side wall protrude radially inwardly from the inner surface of the axial side wall; or Preferably, wherein at least a portion of the protection elements comprises elongated protection elements extending parallel or nearly parallel to the inner surface of the axial side wall of the axial support structure; or Preferably, wherein at least a portion of the elongate protection element comprises two or more protection element segments connected in series in a row or other pattern; or Preferably, the axial profile and / or the side profile of the protection element comprises at least one or more of a block element, a wing and a fin; or Preferably, wherein the plurality of wear protection elements are arranged to form a framework for a liner having a different material, the liner being arranged to be worn away during a grinding operation to expose the wear protection elements; or Preferably, wherein the grinding element has a cage-like structure, in which the axial support structure comprises a plurality of spaced-apart elongated support members defining the outer periphery of the grinding element, and the at least one opposing disc is connected to the plurality of spaced-apart elongated support members of the axial support structure and is arranged to protrude radially inwardly from the plurality of spaced-apart elongated support members; or Preferably, wherein at least a portion of the plurality of spaced-apart elongated support members are arranged to extend parallel or nearly parallel to the axial direction, and / or to extend obliquely relative to the axial direction, and / or to extend non-linearly relative to the axial direction; or Preferably, wherein at least a portion of said plurality of spaced apart elongated support members comprises curved support beams; or Preferably, wherein the plurality of spaced apart elongate support members are arranged to form a framework for a liner of a different material, the liner being arranged to be worn away during a grinding operation to expose the spaced apart elongate support members; or Preferably, the at least one opposing disk comprises a castellated structure located on one side of the opposing disk; or Preferably, the at least one opposing disk comprises a castellated structure located on both sides of the opposing disk; or Preferably, wherein the at least one opposing disk comprises a castellated structure located on a radially inner edge of the opposing disk; or Preferably, wherein the castellated structure comprises spaced apart components at intervals of 10-60 degrees, preferably at intervals of 10-45 degrees, more preferably at intervals of 10-30 degrees, most preferably at intervals of 10-20 degrees in a tangential direction; or Preferably, wherein the height of the castellations in the axial direction is in the range of 0.5 to 3 times the axial thickness of the opposing disc, preferably approximately the same as the thickness of the opposing disc; or Preferably, wherein the height of the castellations is in the range of 2 mm to 200 mm, preferably in the range of 5 mm to 150 mm, more preferably in the range of 10 mm to 100 mm; or Preferably, wherein the ratio of the height of the castellations to the spacing of the castellations is in the range of 1 / 2 to 1 / 20, preferably in the range of 1 / 5 to 1 / 20, more preferably in the range of 1 / 8 to 1 / 12; or Preferably, wherein the width of the castellations in the tangential direction is from 1 mm to about the thickness of the opposing disc, preferably from 5 mm to about the thickness of the opposing disc, more preferably about the thickness of the opposing disc; or Preferably, the total width of all the castellations in the tangential direction is less than 0.25 to 0.35 times the tangential length of the grinding element; or Preferably, wherein the orientation of the castellations is tilted in the range of 0 to 90 degrees, preferably in the range of 0 to 25 degrees, more preferably in the range of 0 to 10 degrees relative to the radial direction of the opposing disk; or Preferably, wherein the castellations extend across the opposed discs from the axial support structure to the radially inner edge of the opposed discs; or Preferably, wherein the castellated structure extends across a portion of the opposing disc between the axial support structure to the radial inner edge of the opposing disc, preferably across an inner portion of the opposing disc adjacent the inner edge of the opposing disc; or Preferably, wherein the castellations extend beyond a radially inner edge of the opposing disc, preferably extend around said radially inner edge to join to a castellation on an opposite side of the opposing disc; or Preferably, wherein the castellations are located only on the radially inner edges of the opposing disks; or Preferably, the grinding element is a separate element that can be loosely mounted in the grinding housing; or Preferably, wherein the grinding element is connectable to one or more other grinding elements to form a larger self-contained grinding element assembly that can be loosely mounted within a grinding housing; or Preferably, wherein the grinding element is configured for use with grinding media having a diameter selectable from the range of approximately 0.5-20 mm depending on the F80 of the particulate material and the P80 of the ground particulate material in each specific grinding application; or Preferably, wherein the grinding element is a refurbished grinding element.

3. A grinding element assembly comprising a plurality of grinding elements according to any one of claims 1 to 2.

4. An agitator bead mill comprising a substantially cylindrical grinding shell and a central agitator shaft located in the grinding shell, and at least one grinding element according to any one of claims 1 to 2; or Preferably, wherein A central stirring shaft is provided with stirring elements, preferably grinding discs, spaced axially along the central stirring shaft; or Preferably, the agitated bead mill comprises a vertical or horizontal disc mill.

5. Use of a grinding element according to any one of claims 1 to 2 for grinding mineral ores.

6. Use of a grinding element according to any one of claims 1 to 2, wherein the diameter of the grinding media can be selected from the range of approximately 0.5-20 mm depending on the F80 of the granular material and the P80 of the ground granular material in each specific grinding application.

7. A method for refurbishing a grinding element according to any one of claims 1 to 2, the method comprising: removing the grinding elements from the agitator bead mill, and Replace or rebuild worn castellations of grinding elements.

8. The method according to claim 7, wherein: Reconstruction involves building spare parts of a castle-like structure to replace worn-out material; or Preferably, wherein rebuilding comprises constructing a castellated structure spare part to replace the worn material using one or more of the following techniques: deposition welding, 3D printing, adding rubber or polymer to the worn area; or Preferably, wherein replacing comprises attaching the new castellated structure to the grinding element by one or more of bolting, riveting, welding, gluing and bonding.

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