Ceramic plates for internal coating of vertical mills

Description

"Ceramic tiles for wall cladding" "INTERNAL OF VERTICAL MILLS"

[0001] This utility model application refers to a “CERAMIC PLATES FOR INTERNAL LINING OF VERTICAL MILLS”, developed with the purpose of providing wear plates for vertical mill shells used in the cement industry, manufactured in high alumina ceramic and with optimized geometry, in order to guarantee greater durability, performance and operational efficiency. State of the art

[0002] The vertical cement mill is a large piece of cement grinding equipment. Wear phenomena are of great importance to industry in its various segments due to the effects they cause on components and equipment, often rendering them unusable. This occurs because wear causes mass loss, culminating in changes in the geometry of the part. Therefore, especially for maintenance sectors, studying and understanding wear mechanisms is essential in order to delay its action by using more suitable materials and controlling the costs related to replacing parts that fail.

[0003] The cement industry, whose electricity costs are extremely high, has been seeking to use increasingly efficient equipment. In this way, the emergence of the vertical roller mill, intended to replace traditional tubular ball mills, has shown significant gains in this regard, as it can reduce energy consumption by approximately 40%. However, the new equipment has disadvantages in terms of maintenance, as its rollers and table wear out considerably due to the extremely abrasive environment. Petition 870250096402, dated 10 / 22 / 2025, p. 15 / 25 2 / 9 and within a few months they cease to offer adequate working conditions.

[0004] Due to the costs involved, both related to the recovery procedure and the loss of production, it is necessary to continuously assess wear on the mill in order to optimize this downtime, making the most of the applied coating, but at the same time preventing wear from exceeding the limits recommended by the manufacturer to ensure that the equipment does not suffer irreparable damage.

[0005] The science that studies the interaction between moving surfaces is called tribology. This interaction gives rise to various types of wear that shorten the life of mechanical components.

[0006] Often, metal parts are considered unusable not because they are faulty, but because of wear and tear, which causes a loss of dimensions and consequently of functionality.

[0007] The wear and tear of mechanical components represents high costs for maintenance sectors in various industry segments, as many pieces of equipment operate under severe conditions and wear out quickly, generating the need to replace compromised components. For the same reason, such parts are usually oversized, which also leads to a higher aggregate cost, and in addition, these components may end up suffering premature wear and failing unexpectedly, causing equipment downtime and production losses.

[0008] Therefore, the study of wear is very important in order to better understand its mechanisms and try to minimize its destructive effect, thus making better use of the components. Petition 870250096402, dated 10 / 22 / 2025, page 16 / 25 3 / 9 mechanics affected, decreasing costs and increasing process reliability.

[0009] Among the wear mechanisms, abrasion is the most studied due to its importance, as it is the cause of about 50% of material loss due to wear.

[0010] Abrasive wear occurs whenever a solid object collides with particles of materials that have equal or greater hardness than it. The extent of abrasive wear is much greater than it appears, since often a material considered soft can cause abrasive wear if it has particles of high hardness dispersed in its matrix. Furthermore, for a long time it was believed that abrasive wear occurred only due to particles that have a hardness greater than the surface analyzed, since during contact these would have an action similar to the cutting processes performed by machine tools. However, today it is known that there are other indirect mechanisms involved, such as the removal of individual grains, microfractures, and the acceleration of fatigue due to repeated deformations.

[0011] Wear mechanisms are associated with high costs in various industry segments. Many worn components must be replaced at the end of their useful life; however, in some situations it is possible to recover them. Welding processes prove to be highly versatile for this purpose, and in many cases present considerably lower costs.

[0012] Cement is a ceramic material of extreme importance to the construction industry, being one of the world's main commodities and even serving as an economic indicator. Its basic raw materials are limestone, clays, gypsum, and iron ore. Initially, a mixture of Petition 870250096402, dated 10 / 22 / 2025, page 17 / 25 4 / 9 Limestone, clay, and iron ore undergo a calcination process to produce clinker, which is the basis for cement production. After this process, to actually produce cement, other components are added to the clinker, varying according to the type of cement, in a final grinding process.

[0013] Crushing and grinding processes are the biggest contributors to this electricity consumption. For this reason, the use of vertical roller mills instead of ball mills has been increasing. Vertical mills have gained ground because, in addition to having lower specific energy consumption, resulting in reduced process costs, they are more compact, which saves space. The industry's search for an efficient mill that provides optimal comminution conditions, high productivity, and low cost per ton has been met.

[0014] Another advantage of the vertical roller mill is that it integrates several activities of the production process into a single piece of equipment; grinding, homogenization, drying, and classification of the material take place within it, unlike the ball mill, which requires an external classifier.

[0015] The grinding process aims to reduce the material particles to the desired granulometry. The vertical roller mill accomplishes this through a combination of impact, compression, abrasion, and friction.

[0016] The main components of a vertical roller mill are: casing, grinding table, grinding rollers, drive system, hydraulic loading system, nozzle ring, dam ring and solids fraction separator.

[0017] Patent BR 11 2023 027114 2 refers to a method for predicting a wear level of a wear component of a mill. Petition 870250096402, dated 10 / 22 / 2025, page 18 / 25 5 / 9 vertical, whereby the vertical mill is used to grind feed material. The method includes, while the mill is in operation, (i) capturing / obtaining a thermal profile of the mill from outside a grinding chamber of the mill, and (ii) determining an indication as to a wear level of at least one wear component of the mill which is located inside the grinding chamber, based on the thermal profile of the mill. The step of capturing / obtaining a thermal profile may include performing a thermographic analysis of the mill from outside the grinding chamber of the mill. The determination step may include determining whether the wear component requires replacement / substitution based on the thermographic analysis of the mill.

[0018] Patent R 11 2023 023096 9 refers to a system for assembling and / or disassembling a lining element (10) for a mill shell (2), wherein the system comprises: one or more lining lifting elements (110), each structured and arranged to be fixed (tightened) in a respective side-to-side hole of the lining element (16) in such a way that said one or more lining lifting elements project outward (protrude) from the front side of the lining element to define associated lifting portions to enable engagement with a lifting tool; and one or more fastening (tightening) screws (130) for fixing the lining element to the mill shell. The present invention further refers to methods for assembling and disassembling a lining element for a mill shell.

[0019] Patent BR 11 2016 007937 0 deals with a base lining for a rotary crusher and a base lining assembly where protective linings are installed over and around the respective joints. Petition 870250096402, dated 10 / 22 / 2025, page 19 / 25 6 / 9 support joints (106) extending radially between the base lining wall and a central wheel hub (107). The support joints (106) comprise a seat or saddle region with at least a part of the lining positioned in contact with and supported by the seat for distributing the mass of the lining radially between the wheel hub (107) and the lining wall and for reducing the stress on the primary fastening pins.

[0020] Currently, the coating of the shell in vertical mills is made with: - Metal plates with overlay (chromium carbide or similar): - Limited lifespan (on average 6-8 months) - High weight - Rough surface that affects the fluidity of the material and precipitates wear. - Constant generation of metallic waste - High maintenance frequency. Frequent stops for repairs and maintenance. - Frequent exposure of the employee to a confined environment with high temperatures.

[0021] They require constant repairs and welding at the sheet joints, which increases the cost of man-hours and keeps employees exposed to a confined, high-temperature environment.

[0022] Another objective of this application is to present ceramic wear plates that offer superior service life, lower weight, greater efficiency and less structural wear, in addition to reducing the worker's exposure to confined and high-temperature environments.

[0023] Another objective of the present application is to present modular wear plates, manufactured from high-alumina ceramic, for application in Petition 870250096402, dated 10 / 22 / 2025, page 20 / 25 7 / 9 grinding chamber shell for vertical mills, replacing traditional metal plates with a rough coating or overlay.

[0024] Another objective of the present application is to present a wear plate intended for the internal lining of the vertical mill shell, protecting the structure against intense abrasive wear generated by friction with the ground material (limestone, clinker, slag, etc.), maintaining process efficiency and increasing the service life of the equipment.

[0025] It is also the objective of this application to present wear plates with interlocking assembly, which prevent preferential wear and attack on joints / welds, both horizontally and vertically, providing greater safety and durability, especially since it is a high-alumina ceramic coating with a low coefficient of friction, as there is no welding at the joints of the plates.

[0026] Another objective of this application is to present high-alumina ceramic plates, whose composition and shape are primarily intended to combat wear. Their modular, curved, and inclined shape allows for a perfect fit in the mill shell, becoming responsible for absorbing the abrasive wear of the moving particles.

[0027] Another objective of the present application is to present wear plates with a specific geometry that precisely conforms to the shape of the shell, without presenting surface roughness, favoring the flow of the ground material, since the concept of plates without right angles avoids the formation of preferential paths in the plate joints and welds.

[0028] Another objective of the present application is to present wear plates with a stud weld or snap-fit ​​fastening system, guaranteeing a secure mechanical fastening, even under conditions of vibration and high temperatures. Petition 870250096402, dated 10 / 22 / 2025, page 21 / 25 8 / 9

[0029] In order to obtain a perfect understanding of what has been developed, these are only illustrative drawings to which numerical references are made together with a detailed description that follows, where a: Figure 1 shows a perspective view of the cone of the current state of the art without any coating. Figure 2 shows a perspective view of the assembled cone with coating. Figure 3 shows a perspective view of the assembled vehicle. Figure 4 shows a perspective view of the plate. Figure 5 shows a view of the plate alluding to sections AA and EE. Figure 6 shows a view of section AA. Figure 7 shows a view of section EE. Figure 8 shows a view of the plate alluding to the GG cuts. Figure 9 shows a view of section GG. Figure 10 shows a view of detail H.

[0030] As illustrated in the figures and their details, the “CERAMIC PLATES FOR INTERNAL LINING OF VERTICAL MILLS” comprises carbon plates (1), in an arc shape (2), characterized by the carbon plates (1) receiving, on their upper face (3), high alumina 95% ceramic plates (4), the carbon plates (1) having holes (5) fitted with bushings (6), for fitting with clearance of pins fixed to the mill shell, around which layers of solder (7) are applied, while the high alumina 95% ceramic plates (4) have through holes (8), concentric to the conical holes (5), and closed by plugs (9) of the same high alumina 95% ceramic. The carbon plates (1) and the high alumina 95% ceramic plates (4) are Petition 870250096402, dated 10 / 22 / 2025, page 22 / 25 9 / 9 still equipped with flat side walls (10), as well as top (11) and bottom (12) walls with cutouts (13) arranged alternately.

[0031] Based on the description, we can verify that the “CERAMIC PLATES FOR INTERNAL LINING OF VERTICAL MILLS” offers enormous advantages, as the developed plates are made of high alumina ceramic (Al2Os), a material with very high resistance to abrasion, impact, and temperature. In addition, its configuration optimizes the flow of ground material, avoiding turbulence, the preferred path of wear, in the wear plates of the shell as well as in the joints / junctions between the plates, and the accumulation of material, as well as a very long service life and reduced wear.

[0032] In addition, the non-rough surface finish with very low coefficient of friction of the plates promotes continuous flow, reducing friction and contributing to the efficiency of the equipment.

[0033] Since during the operation of a vertical mill, the fed material is compressed and rubbed between the grinding rollers and the grinding table. The moving particles collide with the inner walls of the mill (shell), where the wear plates are installed.

[0034] We should also point out that its optimized geometry is specific to the armor shape, with a non-rough surface, contributing to the reduction of wear due to lateral friction and optimization of the internal flow of particles.

[0035] Because it is innovative and not previously understood in the state of the art, it perfectly fits within the criteria that define an invention patent. Its claims are as follows.

Claims

1 - “CERAMIC PLATES FOR INTERNAL LINING OF VERTICAL MILLS” comprising carbon plates (1), in arc shape (2), characterized in that the carbon plates (1) receive, on their upper face (3), high alumina 95% ceramic plates (4), the carbon plates (1) having holes (5) provided with bushings (6), for fitting with clearance of pins fixed to the mill shell, around which layers of solder (7) are applied, while the high alumina 95% ceramic plates (4) have through holes (8), concentric to the conical holes (5), and closed by plugs (9) of the same high alumina 95% ceramic. The carbon plates (1) and the 95% high alumina ceramic plates (4) are also provided with flat side walls (10), as well as top (11) and bottom (12) walls with alternating cutouts (13).

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