Integrated composite material crushing roller

Abstract

The present invention relates to an integrated grinding roller (1) for a vertical shaft grinder manufactured by casting into a metal mold in a foundry, wherein the roller includes a perforated reinforcement structure (2) around it, consisting of a plurality of ceramic inserts continuously joined to each other, and the continuous assembly of ceramic reinforcements runs along a wavy line.

Description

Technical Field

[0001] The present invention relates to composite wear parts cast by casting iron-based alloys. More specifically, it relates to an integral grinding roller, which is reinforced by a perforated ceramic structure incorporated into the roller together with a specific assembly of reinforcing elements capable of adapting to wear stress by creating differentiated perforations. A method for manufacturing the roller is also disclosed.

Background Art

[0002] Cast composite wear parts are known to those skilled in the art. These are mainly cast iron parts that are locally reinforced by alumina-zirconia type ceramics, or carbides, nitrides, borides or other intermetallic compound elements on the surface most exposed to wear. These ceramics have a studied geometric shape and are appropriately arranged within the metal matrix.

[0003] The specific arrangement of the reinforcement structure specifically enables the creation of a hierarchical composite with reinforcing materials, which are differentiated by the arrangement or geometry of ceramic reinforcing materials generally composed of an aggregate of granules into which the casting metal can penetrate. Thus, it is possible to produce an aggregate of granules with an average size of 3 mm to 8 mm and having a gap on the order of 1 mm to 3 mm to allow penetration by liquid cast iron during casting. Therefore, for example, a "cake" or "wafer" in the form of a honeycomb-type perforated structure can be formed. These "inserts" are usually arranged in a studied manner inside the sand mold on the most stressed surface of the wear part. These "inserts" are called "padding". When these cakes are individually infiltrated before being placed in the mold and cooled, they are called "bars".

[0004] The present invention aims to improve the wear resistance of grinding rollers for mills in general, particularly those called vertical axis mills. Vertical axis mills are used, for example, to grind coal, raw material mixes, or cement clinker. They consist of a rotating track, which supports rollers driven by the rotational movement of the track along a vertical axis (see Figure 1). The material to be ground is introduced through a central feed path and falls onto the track, where it is crushed and ground by the rollers. This principle is illustrated in detail in Figure 2. The ground material is then discharged around the track by centrifugal force and collected in a blower equipped with a cyclone, which allows for the recirculation of material that has not yet been sufficiently ground. Various types of roller shapes are possible, but frustoconical and annular rollers are the most common.

[0005] Patent Document 1 discloses a cast composite wear part comprising a honeycomb-shaped ceramic reinforcement and an alumina-zirconia-based ceramic.

[0006] Patent Document 2 discloses a grinding roller made of a material highly resistant to wear and comprising a plurality of peripheral bars mechanically sealed within a cast matrix made of a ductile material, wherein the roller includes regions that experience high wear stress and regions that experience low wear stress, and the roller has bars on its peripheral surface that have a continuous portion in the region that experiences the greatest stress and a discontinuous portion in the region that experiences the least wear stress, and the gap in the discontinuous portion is filled with the ductile material of the cast matrix, enabling mechanical sealing of the bars.

[0007] Patent Document 3 discloses a grinding roller for a vertical axis mill cast by casting a metal matrix, the roller including a plurality of reinforcing inserts around it, several portions of the circumferential surface of the same inserts positioned at different distances from the roller's periphery depending on wear stress.

[0008] Patent Document 4 discloses a grinding roller in which the area subject to wear is reinforced in a differentiated manner with ceramic inserts including blind holes and through holes, the blind side of the blind holes is oriented toward the side that is subjected to the most stress due to wear. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] International Publication No. 98 / 15373 pamphlet [Patent Document 2] International Publication No. 2005 / 084809 Pamphlet [Patent Document 3] International Publication No. 2018 / 069006 Brochure [Patent Document 4] International Publication No. 2021 / 1160381 brochure [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide an integrated composite grinding roller equipped with a ceramic reinforcement composed of multiple inserts of improved shape, both in structure and arrangement, that are suitable for wear stress. In particular, it aims to eliminate the straight lines between continuous ceramic inserts that constitute the wear propagation initiation point and preferred path. [Means for solving the problem]

[0011] The present invention discloses a one-piece grinding roller for a vertical axis mill, cast by casting a metal matrix, the roller comprising a perforated reinforcement structure around it consisting of a plurality of continuously assembled ceramic inserts, the continuous assembly of ceramic reinforcements being manufactured along a wavy line.

[0012] Preferred embodiments of the present invention have at least one of the following features, or any suitable combination thereof. The reinforcing structure 2 includes at least a first region 21 which is least perforated and most frequently subjected to abrasion, and at least a second region 22 which is most perforated and least frequently subjected to abrasion. The first and second regions 21 and 22 of the multiple ceramic inserts are formed by multiple overlapping rings, and the inserts are assembled in an alternating, continuous manner along the wavy lines. The first region 21, which is most frequently subjected to wear, is perforated by frustoconical through-holes 3 whose diameter gradually decreases toward the periphery of the roller, or by a combination of blind holes with their blind sides positioned toward the periphery of the roller and through-holes 4 of any shape. The perforations in the second region 22, which are least exposed to wear, are formed by through-holes 4 of any shape, preferably cylindrical, and are positioned perpendicular or inclined to the surface around the roller. Multiple inserts are assembled to form a frustoconical or annular roller. The amplitude of the dashed line (a) is between 2% and 20%, preferably between 5% and 15%, of the length "L" of the ceramic insert. The amplitude (A) of the wavy line is between 2% and 20%, preferably between 3% and 15%, of the width "l" of the ceramic insert. The ceramic composition of the reinforcing structure is selected from oxides, carbides, nitrides, and borides. The ceramic insert comprises an aggregate of ceramic-metal composite particles, in which micrometer-sized ceramic particles are bound together with a metal binder, and the composite particles have an average size of 2 mm to 8 mm, preferably 3 mm to 6 mm, determined by sieving with a square mesh or by a Retsch Camsizer according to standard 13322-2:2006. 50 It has, Ceramic-metal composite granules are bonded with a metal binder and have an average size D between 3 μm and 20 μm, preferably between 5 μm and 15 μm. 50The material contains titanium carbide, and the particle size can be measured by laser diffraction using MIE theory, for example, using a Malvern Mastersizer 2000, with the refractive index set to 3 and the absorptivity to 1, according to the instructions in standard ISO 13320:2020. The obscuration should be in the range of 10% to 15%, and the weighted residual should be less than 1%. The ceramic composition of the reinforcing structure in the first region 21 is different from the ceramic composition of the second region 22.

[0013] The present invention also discloses a method for manufacturing a grinding roller according to the present invention, which includes the following steps. A step of providing a mold for manufacturing a one-piece grinding roller by casting an iron-based alloy, A reinforcing structure is arranged consisting of multiple ceramic inserts assembled in a continuous manner along a wavy line, the inserts being in the form of perforated aggregates of millimeter-sized granules, the aggregates being permeable and thus permeable in steps. Steps include impregnating the insert with a liquid iron-based alloy, The step of cooling the grinding rollers and removing them from the mold.

[0014] The method according to the present invention preferably has at least one of the following features, or any suitable combination thereof. Iron-based alloys include steel or cast iron. The reinforcing structure includes at least a first region 21 which is least perforated and most frequently subjected to abrasion, and at least a second region 22 which is most perforated and least frequently subjected to abrasion. The permeable aggregate of millimeter-sized ceramic granules used in grinding roller inserts is selected from the following compositions. Alumina-zirconia, which allows for the stabilization of zirconia with yttria in a ratio of 90 / 10 to 10 / 90. • Powdered carbon and titanium, optionally containing iron powder, as a moderator and precursor for a self-propagating thermosynthesis (SHS) reaction initiated by the casting of iron-based alloys. · A ceramic-metal composite material of titanium carbide hardened with a metal binder.

[0015] In the following figures with annotations, the inserts are shown schematically. In reality, these ceramic inserts are, for example, permeable three-dimensional structures formed of permeable aggregates of millimetric (with an average size of 2 mm to 8 mm, preferably 3 mm to 6 mm) granules assembled by an adhesive with millimetric gaps through which the casting metal can penetrate.

[0016] For the sake of simplicity, the figure only shows the outline of these inserts arranged in the reinforcing part of the grinding roller.

Brief Description of the Drawings

[0017] [Figure 1] An example of a vertical shaft mill equipped with a frustoconical grinding roller pressed against and rotating on a rotating table to which the ore to be crushed is supplied is shown. [Figure 2] The principle of grinding by a frustoconical grinding roller is shown. [Figure 3] A grinding roller made of a bar reinforced with ceramic according to prior art patent document 2 is shown. In this case, a plurality of ceramic inserts in the form of honeycombs are individually infiltrated so as to form the bar before being cooled and placed in a mold, always maintaining the distance between each individual reinforcing element (discontinuous assembly), allowing the casting metal to penetrate between the individual elements, and ensuring the sealing of the assembly within the casting roller. [Figure 4a] A bar made of a metal matrix incorporating ceramic inserts in the form of honeycombs is shown. [Figure 4b] Details of the assembly of the bar before casting of the grinding roller are shown. [Figure 5]The image below shows a frustoconical grinding roller that is severely worn. This is a prior art grinding roller, manufactured according to the techniques shown in Figures 3, 4a, and 4b. Inside, a honeycomb-shaped ceramic structure is visible, highlighted through a severely eroded metal matrix. The spaces (straight grooves) left between the individual bars are also severely eroded. [Figure 6] The image shows an annular grinding roller with a significant level of wear. This is manufactured by placing permeated and cooled bars into a mold, according to prior art document Patent Document 2, while maintaining distance between the bars to ensure that the bars are properly sealed within the roller. [Figure 7a] This shows an annular, integrated grinding roller according to the present invention. [Figure 7b] This only shows the assembly of the corresponding perforating inserts, which are assembled in a single ring along a continuous wavy line. [Figure 8a] This shows an annular, integrated grinding roller according to the present invention. [Figure 8b] This only shows the assembly of the corresponding perforating inserts, which are assembled on two overlapping rings in an alternating, continuous pattern along the wavy lines. [Figure 9a] This shows a frustoconical, integrated grinding roller according to the present invention. [Figure 9b] This only shows the assembly of the corresponding perforating inserts, which are assembled in a single ring along the wavy lines. [Figure 10]Figure 9a shows an integrated frustoconical grinding roller according to the present invention, similar to that shown in Figure 9a, with multiple perforated ceramic inserts arranged continuously along the dashed lines. However, two types of openings (cells) are shown therein, with differentiated perforation ratios adapted to the wear stress for a specific application. The perforated inserts represent two regions 21 and 22. Region 21, which is most exposed to wear, has a limited degree of perforation, with conical holes located where the wear stress is greatest, and the diameter of the cone changes by decreasing from the inside to the outside of the roller. Region 22, which is subjected to the least wear stress, has a larger perforation ratio and includes cylindrical holes perpendicular to the grinding surface. These holes can also form normals and angles to the surrounding surface. [Figure 11a] The present invention illustrates an integrated annular grinding roller, in which multiple perforated ceramic inserts are arranged continuously along a wavy line. Two types of openings with differentiated perforation ratios adapted to specific wear stresses are also shown therein. In this case as well, the perforated inserts also represent two regions 21 and 22. [Figure 11b] The image shows several assembled inserts of the grinding roller before casting, individually. It should be noted that the insert assemblies are not only continuous but also have complementary shapes that allow the elements to be fully assembled with adjacent elements. The wavy assemblies are selected to avoid straight lines that constitute the preferred starting points and paths of wear. While such wear, once initiated, propagates very easily along straight lines, the more or less significant wavy lines can delay or even prevent this phenomenon. Furthermore, tests have shown that simple curved continuous lines of assemblies with low amplitude and no waves provide only an intermediate result between straight lines and continuous wavy lines, although wear paths propagate more easily than with continuous straight lines. [Figure 12]This shows other possibilities for assembling the inserts according to the present invention. The inserts can be dedicated to regions 21 and 22 and can form multiple overlapping rings that may have different dimensions. When the inserts are dedicated to regions 21 and 22, which have high and low wear stress, respectively, it is preferable to arrange them alternately to prevent wear propagation along the continuous line as much as possible. This figure also shows in detail the significant difference in drilling between regions 21 and 22, which have frustoconical holes 3 and cylindrical holes 4 as an example (details not shown). [Figure 13] This shows other possibilities for assembling the inserts according to the present invention. The inserts can be dedicated to regions 21 and 22 and can form multiple overlapping rings that may have different dimensions. When the inserts are dedicated to regions 21 and 22, which have high and low wear stress, respectively, it is preferable to arrange them alternately to prevent wear propagation along the continuous line as much as possible. This figure also shows in detail the significant difference in drilling between regions 21 and 22, which have frustoconical holes 3 and cylindrical holes 4 as an example (details not shown). [Figure 14a] This shows a large, cast annular grinding roller. Two distinct regions 21 and 22, adapted to different stresses, are distinguished within it. The insert consists of two overlapping rings arranged alternately. This configuration is necessary because the grinding roller may tilt slightly on the rotary table. [Figure 14b] This shows the assembly of the corresponding inserts for a large cast annular grinding roller. Two distinct regions 21 and 22, adapted to different stresses, are also distinguished within this assembly. The inserts are arranged with two rings overlapping and staggered. This configuration is necessary because the grinding roller may tilt (incline) slightly on the rotary table. [Figure 15a]This shows an assembly of an insert for an annular grinding roller. In this case, it is a very large roller (18 tons, 3 m in diameter). Two separate regions 21 and 22, adapted to different stresses, are distinguished within it. The insert consists of three overlapping rings arranged alternately. The high-stress regions are located on either side of the lower-stress regions. This symmetrical arrangement allows for the use of a grinding roller that is slightly tilted alternately on both sides on a rotary table. When one side wears down, the roller can be rotated. [Figure 15b] This shows a cast grinding roller. In this case, it is a very large roller (18 tons, 3 m in diameter). Two separate regions 21 and 22, adapted to different stresses, are distinguished within it. The insert consists of three overlapping rings arranged alternately. The high-stress regions are located on either side of the lower-stress regions. This symmetrical arrangement allows for the use of grinding rollers that are alternately slightly inclined on both sides on a rotary table. When one side wears down, the roller can be rotated. [Figure 16] This shows a reinforcing insert having a length "L", a width "l", and a wave amplitude "A" over that width "l", and a method for measuring these. [Figure 17] The diagram shows an assembly with different inserts arranged alternately, and it can be seen that the amplitude of the wave is not necessarily the same across the same line of the assembly. The amplitude is measured in terms of the absolute value between the minimum and maximum values ​​of the wave, as "A" or "A'" relative to the width "l" of the assembled insert, or "a" relative to the length "L" or "L'" of the assembled insert. The amplitudes "A" and "a" are evaluated as percentages of the width "l" and length "L", respectively. [Figure 18] This document describes a method for measuring the wear profile of an annular grinding roller using a rod for comparison with the surface of a new grinding roller. [Figure 19] This shows the wear profile of a frustoconical grinding roller, with thick arrows indicating the location of maximum wear, which is a critical factor in determining roller replacement. [Modes for carrying out the invention]

[0018] Cast wear parts are widely used in the mining and cement industries for crushing rocks and ores. These include tables and grinding rollers of vertical compression mills, and in particular truncated cone and annular grinding rollers as exemplified by the present invention.

[0019] To increase the wear resistance of the grinding rollers, cast iron or steel-type iron alloys are combined with ceramic materials of varying hardness (such as various types of carbides, nitrides, oxides, etc.) that have good resistance to wear.

[0020] However, combining these two types of materials is not easy because they have very different coefficients of thermal expansion, which can generate microcracks during the cooling of the parts, potentially canceling out this synergistic effect in composite wear parts through these defects.

[0021] Another difficulty lies in the fact that the liquid cast iron tends to cool when in contact with the ceramic insert, thus hindering complete penetration of the ceramic insert.

[0022] Numerous configurations of ceramic inserts have been tested by manufacturers. The most popular ceramic inserts are those with a "honeycomb" shape, which is relatively easy to penetrate, such as the one cited in Prior Art Patent Document 1.

[0023] Ceramic reinforcements are typically introduced in the form of bars, and therefore as inserts into which liquid cast iron has already permeated the gaps, and after cooling, are reintroduced into a mold for casting the wear portion as the desired single block to be obtained. This technique is shown in Figures 3 to 5 of this book and is the subject of Patent Document 2.

[0024] Ceramic inserts must have a permeable structure to allow liquid cast iron to penetrate, and the level of permeability is a critical factor, thus involving many skills in their manufacture. This has led to a series of techniques for producing powder aggregates (aggregates) in the form of several-millimeter-sized particles that are then assembled into a "cake / wafer" structure in a mold and compressed by vibration. When they leave the mold, these inserts always have irregular gaps on the order of 1 mm to 5 mm.

[0025] Many compositions are possible for the manufacture of ceramic inserts that can be used in the reinforced grinding rollers according to the present invention. In a non-extensive list, for example, the following can be mentioned: Alumina-zirconia in the form of millimeter-sized granules, with or without yttria stabilization, 10 / 90 to 90 / 10, assembled into aggregates by inorganic adhesive in a structure that is permeable to molten metal and therefore permeable to conventional casting, Particles resulting from metal-ceramic composites that are ground or sintered from a mixture of powders based on carbides, nitrides, borides, or intermetallic elements, which are solidified with a metal binder before being aggregated into a permeable structure into which molten iron-based alloys can penetrate. Ceramics formed by self-propagating exothermic synthesis (SHS) from carbon and titanium powders, such as titanium carbide, can be in the form of millimeter-sized aggregated granules with millimeter-sized voids, and can be mixed with powders to mitigate the reaction, such as iron powder. The reaction between carbon and titanium is initiated by casting of an iron-based alloy.

[0026] Holding the insert in the mold during casting also requires a certain level of skill that manufacturers have acquired over many years.

[0027] The configuration and arrangement of ceramic inserts within integrated composite grinding rollers have been the subject of much research, but it has always been concluded that the results regarding wear rates obtained during testing are relatively unpredictable, as they depend on the specific application, i.e., the type of machine used and the type of rock to be ground.

[0028] The situation is further complicated by the fact that during wear, the shape of the grinding roller changes, and areas that initially experience only slight stress can experience much greater stress as the wear progresses. Therefore, it is often necessary to make compromises regarding the structure of the insert that allow for a balance between short-term and long-term wear, and these two concepts can vary considerably from case to case.

[0029] The inventors of the grinding roller according to the present invention have now created a reinforcing structure including multiple ceramic inserts to address this compromise. This reinforcing structure is adapted to the final shape of the roller, for example, a frustoconical or annular overall shape, and includes assemblies of ceramic inserts that can take different forms, such as a continuous assembly with inserts having approximately the same dimensions as the grinding roller arranged around its circumference, or two or more "rings" of ceramic inserts superimposed along a wavy line. The assembly of one or more rings depends largely on the final size of the roller, insofar as there are still limitations to the feasibility of the inserts due to handling reasons by the operator (mass, volume, brittleness). For example, a roller weighing 1 ton may only require the assembly of one ring with a limited number of inserts, while a roller weighing more than 15 tons will require at least two or three rings with a large number of superimposed inserts (see, for example, Figure 15b).

[0030] Depending on the stress in a specific application, it is possible to assume differentiated perforations depending on the position of the insert within the roller. For example, different ratios of perforations can be assumed depending on whether the side with the greatest wear stress is related to region 21, or whether the side with the least wear stress is related to region 22. An example of a ring assembly of this type of insert for an annular grinding roller is shown in Figure 11a, and an example of two rings stacked is shown in Figure 14a. Three stacked rings of inserts are shown in Figure 15b. To avoid the propagation of wear along a predetermined line, the stacked inserts are preferably assembled in an alternating pattern.

[0031] The perforated ceramic structure has openings of almost any shape. The openings provided in the insert structure have a diameter between approximately 1 cm and 10 cm, preferably between 1 cm and 8 cm, and particularly preferably between 2 cm and 4 cm. When the perforations are differentiated within the same grinding roller, in the peripheral region 21 which is most exposed to wear, the holes preferably have a frustoconical shape 3 or are combined with blind holes. The most exposed region may also include a clever combination of blind holes and through holes. When blind holes are used, the blind side is positioned on the side that is most stressed by wear. When frustoconical openings 3 are used, the openings gradually narrow toward the outer surface which is most exposed to wear. In the region 22 which is least exposed and has the most perforations, the holes can have any shape, but a cylindrical shape would be preferred (see Figure 12).

[0032] The inventors further observed that both straight lines and slightly curved lines constitute significant starting points for wear on the grinding rollers. Once started, wear propagates much more rapidly in straight lines because there are no obstacles to encounter.

[0033] To mitigate this phenomenon, the inventors eliminated the space between inserts, but technological advancements in their manufacture now allow for better penetration. The insert assemblies according to the present invention are therefore continuous and formed along a wave-like pattern, making it possible to avoid the initiation and propagation of wear along straight lines. While all forms of waves are certainly conceivable, for logistical reasons, parts with a corrugated surface are preferred, all having the same shape and enabling a perfectly continuous, complementary assembly.

[0034] The amplitude of the waves and how they are measured are shown in Figures 16 and 17. In these figures, the amplitude of the waves is exaggerated for illustrative purposes.

[0035] (Examples) Regarding the different rollers according to the present invention, tests were conducted using two different types of vertical rotary mills suitable for the roller to be tested. To compensate for variations due to the effect of ceramic composition on wear, the same ceramic was used in all tests. This is millimeter-sized granules of a titanium carbide-type metal-ceramic composite material bound with a manganese steel-type metal binder. These granules, with an average dimension of approximately 5 mm, were compressed to form perforated inserts with a thickness of approximately 50 mm, and these were used in all tests.

[0036] For the purpose of testing, a configuration was implemented in which the inserts were distributed across multiple rings. However, for a roller weighing, for example, one ton, multiple rings would not necessarily be required. Nevertheless, the inventors wanted to test the behavior of the roller according to the present invention when the inserts were configured on multiple rings that were stacked in an alternating arrangement.

[0037] Each of the two frustoconical rollers was tested for 500 hours in parallel with a reference roller, and wear was extrapolated to 1000 hours. In each of the three annular roller tests, two rollers were alternated with two reference rollers and rotated for 1000 hours. The tests were performed continuously. The test conditions are summarized in the table below.

[0038] [Table 1]

[0039] Roller wear can be initially determined by measuring the profile along the generatrix by pressing a template against an unworn surface. The distance between the roller surface and the template is recorded at multiple points along the template on a representative number of points on the roller's contour (see Figure 18). These measurements are then compared to distances recorded on a new roller. The average wear profile is determined to provide information about the wear pattern, which manufacturers can utilize.

[0040] However, the wear measurement selected to compare the performance characteristics of the rollers is the maximum wear depth on the roller, which is crucial for its replacement. This maximum wear will be used in the following table for performance measurement. Grinding rollers manufactured with the bars shown in Figures 3, 4, and 5 according to Patent Document 2 are used as reference frustoconical and annular rollers for comparison. These reference rollers are combined with the rollers according to the present invention on the same mill each time during testing. In the latter case, wear is measured above the bars, rather than between the bars, on a heavily worn ductile matrix.

[0041] Testing of a Type 1 mill with annular rollers

[0042] [Table 2]

[0043] [Table 3]

[0044] [Table 4]

[0045] Tests on Type 2 mills equipped with frustoconical rollers

[0046] [Table 5]

[0047] [Table 6]

[0048] result

[0049] [Table 7]

[0050] Interpretation of results Compared to the standard annular and frustoconical grinding rollers manufactured using the bar described in Patent Document 2, all grinding rollers according to the present invention show improved wear performance. This improvement ranges from 10% to 27%, which is significant.

[0051] Rollers with differentiated perforations in regions 21 and 22 according to wear stress (Examples 2 (Table 3) and Examples 4 (Table 5) with cells of 13 and 23 mm) exhibit better performance characteristics when the reinforcing insert consists of a single ring assembly with the fewest bonding lines.

[0052] Rollers containing multiple overlapping rings and differentiated perforations exhibit reduced performance due to the increased number of inserts and therefore the increased number of joint lines required for larger grinding rollers.

[0053] Even with non-differentiated perforation without specific regions 21 and 22, an 11% improvement in performance on the annular grinding roller is possible. [Explanation of Symbols]

[0054] 1. Integrated crushing roller 2 Ceramic Inserts 21 The first area of ​​the ceramic insert that is most frequently subjected to wear. 22 The second area of ​​the ceramic insert that is least exposed to wear. 3. Example of a frustoconical opening in a ceramic insert positioned on the surface most frequently subjected to stress from the grinding roller. 4. Example of a cylindrical opening in a ceramic insert positioned on the surface that experiences the least stress from the grinding roller.

Claims

1. A one-piece grinding roller (1) for a vertical axis mill cast by casting a metal matrix, The crushing roller (1) is a single-piece crushing roller (1) having a perforated reinforcing structure (2) made up of a plurality of continuously assembled ceramic inserts around it, and the continuous assembly of the reinforcing material of the ceramic inserts is manufactured along a wavy line.

2. The aforementioned reinforcing structure (2) is At least one first region (21) is the area that is least perforated and most frequently subjected to abrasion, At least a second region (22) where perforation is most frequent and where abrasion is least likely, The integrated grinding roller (1) according to claim 1, including the above.

3. The first region (21) and the second region (22) of the plurality of ceramic inserts are formed by a plurality of overlapping rings. The integrated grinding roller (1) according to claim 1 or 2, wherein the ceramic inserts are assembled in an alternating, continuous manner along the wavy lines.

4. The perforation in the first region (21) that is most frequently subjected to abrasion is The crushing roller is formed by a frustoconical through-hole (3) whose diameter gradually decreases toward the periphery, or An integrated grinding roller (1) according to any one of claims 1 to 3, formed by a combination of a blind hole with a blind side positioned on the periphery side of the grinding roller and a through hole (4) of any shape.

5. The integral grinding roller (1) according to any one of claims 1 to 4, wherein the perforations in the second region (22) that are least exposed to wear are formed by through-holes (4) of any shape, preferably cylindrical, that are positioned perpendicular or inclined to the surrounding surface of the grinding roller.

6. The integral grinding roller (1) according to any one of claims 1 to 5, wherein the plurality of ceramic inserts are assembled to form a frustoconical roller or an annular roller.

7. The amplitude (a) of the wavy line is between 2% and 20%, preferably between 5% and 15%, of the length "L" of the ceramic insert, as described in any one of claims 1 to 6.

8. The amplitude (A) of the wavy line is between 2% and 20%, preferably between 3% and 15%, of the width "l" of the ceramic insert, as described in any one of claims 1 to 7.

9. The integral grinding roller (1) according to any one of claims 1 to 8, wherein the composition of the ceramic of the reinforcing structure is selected from oxides, carbides, nitrides, and borides.

10. The ceramic insert comprises an aggregate of ceramic-metal composite particles, in which ceramic particles in the micrometer range are bound together with a metal binder, and the composite particles have an average size D of 2 mm to 8 mm, preferably 3 mm to 6 mm, as determined by sieving. ５０ An integrated grinding roller (1) according to any one of claims 1 to 9, having the following features.

11. The composite particles are solidified with a metal binder and have an average size D between 3 μm and 20 μm, preferably between 5 μm and 15 μm. ５０ An integrated grinding roller (1) according to claim 10, comprising titanium carbide.

12. The integral grinding roller (1) according to any one of claims 1 to 11, wherein the composition of the ceramic of the reinforcing structure in the first region (21) is different from the composition of the ceramic in the second region (22).

13. A method for manufacturing a grinding roller (1) according to any one of claims 1 to 12, The steps include providing a mold for manufacturing a one-piece grinding roller by casting an iron-based alloy, A step of arranging a reinforcing structure composed of multiple ceramic inserts assembled in a continuous manner along a wavy line, wherein the ceramic inserts are in the form of perforated aggregates of millimeter-sized granules, and the perforated aggregates are permeable, thereby allowing iron-based cast alloys to penetrate, The steps include impregnating the ceramic insert with a liquid iron-based alloy, The steps include cooling the aforementioned crushing roller and removing it from the mold. Methods that include...

14. The method according to claim 13, wherein the iron-based alloy includes steel or cast iron.

15. The aforementioned reinforcing structure is At least one first region (21) is the least perforated and most frequently subjected to abrasion, At least a second region (22) that is most frequently perforated and least exposed to abrasion, The method according to any one of claims 13 and 14, including the method described in any one of claims 13 and 14.

16. The aggregate having permeability to millimeter-sized ceramic granules used as an insert for the grinding roller has the following composition, namely: Alumina-zirconia in a ratio of 90 / 10 to 10 / 90, wherein the zirconia can be stabilized with yttria, A powdered carbon and titanium mixture optionally containing iron powder is used as a moderator and precursor for the self-propagating thermosynthesis (SHS) reaction initiated by the casting of the iron-based alloy. Ceramic-metal composite material of titanium carbide solidified with a metal binder. A method according to any one of claims 13 to 15, selected from the following.

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