EP3840890B1 - Vertical ball mill, stator segment for a vertical ball mill and method for maintaining a vertical ball mill - Google Patents

Description

field of invention

The invention relates to a vertical ball mill, in particular for pre-grinding of ground material such as minerals, a stator segment for a vertical ball mill and a method for maintaining a vertical ball mill.

Technological background

In a ball mill, grinding media are used to grind grist. The material to be ground is taken up in a suspension, which is also referred to as turbidity or slurry, and moved in the mill. The grinding bodies are generally spherical and are also referred to as grinding balls or grinding beads. Ground material is understood to mean, in particular, minerals and mineral aggregates, such as metallic ores, but also substances of similar hardness, such as coal ores, recycling materials, etc. The crushing of minerals is described by way of example in the following description.

In conventional mills, the minerals are mixed with the grinding balls to grind the minerals. A portion of the grinding balls and minerals are raised a predetermined distance by design and fall back from that height into a bed of the rest of the grinding balls and minerals. The falling grinding balls hit lying grinding balls. Minerals that are in between are shattered.

A conventional ball mill can, for example, have a horizontal drum, ie a drum rotating about a horizontal axis, in which minerals are comminuted with the aid of grinding balls. In an agitator mill, gravity is also used as an essential element for generating crushing forces (so-called "gravity induced mills").

In a mill that primarily uses gravity, hydrostatic pressure builds up to aid in the grinding. This design means that the grinding media are repeatedly lifted. This requires lifting work, which is done, for example, by a screw that is driven in rotation. The grinding takes place in a ball bed. The main stress is caused by gravity and to a lesser extent by centrifugal forces. The portion of the grinding forces that is due to gravity cannot be influenced. The material to be ground is also lifted by the screw and recirculates downwards at the periphery. The primary transport of the ground material takes place through the screw, a certain proportion through flow forces in the pulp. Such a grinding or transport mechanism can also cause coarse material to be discharged. This usually requires the use of an external view circuit.

Devices for crushing minerals are built in numerous forms and can be simply referred to as horizontal and vertical mills. From the DE 1 901 593 (A1 ) is a vertically arranged agitator mill with auxiliary grinding bodies for homogenizing, dispersing and comminuting solids in liquids. In the primary industry (mines, etc.), vertically arranged mills have also proven their worth (see e.g WO 2007/019602 A2 ).

As an alternative to this, there are mills in which the comminution forces are predominantly generated in a fluidized grinding bed and can be generated and changed by the speed of a rotor (so-called "fluidized mills"). A vertically aligned mineral mill for fine grinding was used on the occasion of the IMCET 2013 ("23rd International Mining Congress and Exhibition of Turkey", Kemer/Antalya/Turkey, April 16 -19, 2013, in particular Session 1: "Stirred Milling Technology - A new concept in fine grinding", by I. Roitto et al "Outotec HIG-mills: a fine grinding technology "). The presented mineral mill for the fine grinding of pre-ground minerals consists of a vertically oriented stator assembled from two half-shells with fixed ring-shaped grinding discs, which is suspended from a solid platform and a rotor mounted on one side on the shaft with grinding discs arranged In addition to the central rotor, which is driven by geared motors mounted on the platform with an output of up to 5000 kW, the stator also hangs on this platform.The heterogeneous mixture is transported between the rotating grinding discs and stationary grinding discs attached to the housing Water and crushed with grinding media until the ground material reaches the desired grain size and grain distribution. This takes place with a maximum net volume (filling volume) of 30m ³ . The grinding process used (which is sometimes referred to as the HIG process; ultra fine grinding technology) requires pre-treated, multi-stage crushed minerals so that the grinding process can take place at all. The WO 2018/138405 A1 discloses a vertical ball mill in which both the rotor and stator are suspended from a platform.

Disclosure of the Invention and Some Embodiments

Against this background, with the approach presented here, a vertical ball mill, in particular for coarse pre-grinding of minerals, a stator segment for a vertical ball mill and a method for servicing a vertical ball mill are presented according to the independent claims. Advantageous developments and improvements of the approach presented here result from the description and are described in the dependent claims.

Advantageously, embodiments of the present invention may allow reducing energy input for pre-grinding minerals to increase efficiency, and modifying a structural design of a pre-grinding mill such that, among other things, it is easy to assemble, disassemble, and can be serviced.

In particular, the approach presented here creates a robust construction that requires less material and is considerably lighter than previous concepts. The construction can be brought relatively easily to the mining sites of the minerals or to a place of use, partially dismantled. With the approach presented here, required regular maintenance work can be significantly shortened and simplified. The risk of accidents can be reduced by the machine concept. An overhaul of the mill presented can be carried out relatively easily, so that no specially trained technical personnel may be required. The approach presented here can also enable improved process control and easier adaptation to the material quality present in mining. The shredded material can be further processed or refined and/or fed directly to the downstream process. In the case of revisions and repairs, no additional lifting gear is usually required for disassembly and assembly.

Spare parts can be at the same level as the main ones to be replaced Components, such as a mill shaft with grinding discs or individual grinding cylinders, can be stored on site to save space. A few people can safely move and position the spare parts horizontally using rails and rollers, for example. This also includes safe and quick emptying of the grinding cylinder without extensive loss of material.

According to a first aspect of the invention, a vertical ball mill is proposed, in particular for the pre-grinding of ground material such as minerals. The vertical ball mill has (i) a rotor which is supported axially and radially at an upper end and hangs downwards, (ii) a self-supporting stator which radially encloses the rotor and is unloaded by the weight of the rotor, with a tangentially aligned rotor inside a Shape tolerance approximately cylindrical lateral surface, and (iii) a base plate supporting a weight of the stator. In this case, the stator is composed of at least two stator segments which can be separated from one another and are cantilevered in the separate state and can be displaced relative to one another. Each of the stator segments has, on at least one side edge of a wall, a sealing surface for sealing against the respective other stator segment, and on a lower edge a standing surface dimensioned appropriately for the load for sealing against the base plate. Said side edge of the wall here runs from an upper edge of the wall forming the lateral surface to a lower edge of the wall. The stator segment rests upright with the base on the base plate orthogonally within an angular tolerance on a load-bearing surface of the base plate.

Furthermore, according to a second aspect of the invention, a self-supporting stator segment for a vertical ball mill according to the approach presented here is presented. This has (i) a wall approximately in the shape of a segment of a cylinder within a shape tolerance, (ii) at least one sealing surface arranged on a side edge of the wall running from an upper edge of the wall to a lower edge of the wall for sealing on another stator segment, and (iii) one on the Lower edge arranged load-fair dimensioned footprint, with which the stator segment can be set up orthogonally on a load-bearing surface of a base plate of the ball mill within an angular tolerance. A self-supporting stator can be assembled from a plurality of stator segments with a lateral surface formed by the walls and circular-cylindrical within a shape tolerance, which in an assembled state can bear standing loads on the baseplate to support a weight of the stator.

• ein Trennen des Stators in die Statorsegmente, wobei der Stator an den Dichtflächen getrennt wird,
• ein Anordnen von Hilfseinrichtungen unter zumindest einem der Statorsegmente, und ein laterales Verlagern des Statorsegments und der Hilfseinrichtungen unter Verwendung einer Verlagerungseinrichtung.

Furthermore, according to a third aspect of the invention, a method of servicing a vertical ball mill, particularly for pre-milling of grist such as minerals, is presented. The vertical ball mill may correspond to the aforementioned ball mill according to an embodiment of the first aspect of the invention and in turn has a rotor hanging down axially and radially at an upper end, a rotor radially enclosing, unloaded by a weight of the rotor, self-supporting standing Stator with a tangentially aligned to the rotor, within a shape tolerance approximately cylindrical lateral surface, and a weight of the stator supporting base plate. The stator is composed of at least two stator segments which can be separated from one another and are cantilevered in the separate state and can be displaced relative to one another. Each of the stator segments has, on at least one side edge of the wall running from an upper edge of a wall forming the lateral surface to a lower edge of the wall, a sealing surface for sealing on the other stator segment in each case, and on the lower edge a standing surface dimensioned according to the load for sealing on the base plate. The stator segment rests upright with the base on the base plate orthogonally within an angular tolerance on a load-bearing surface of the base plate. The method has at least the following method steps, preferably in the order given:

• separating the stator into the stator segments, with the stator being separated at the sealing surfaces,
• arranging auxiliaries under at least one of the stator segments, and laterally displacing the stator segment and the auxiliaries using a displacement device.

The stator segment can be lifted off the baseplate using jacks and set down on the jacks using the jacks prior to locating the auxiliaries.

Ideas for embodiments of the present invention can be considered as being based on the ideas and findings described below, among other things, but without limiting the invention.

A vertical ball mill can be understood to mean a device for comminuting a material to be ground using grinding bodies. The ground material can be, for example, pre-crushed rock or minerals from a mine. The rock or the minerals can, for example, in a crusher, crushed and sieved in a high pressure bed roller mill, an oxy-fuel or semi-autogenous mill before being fed to the vertical ball mill.

The vertical ball mill described herein can be used as a milling stage of a raw material recovery. The material to be ground is fed to the ball mill in pieces or as a suspension in a liquid carrier medium or transport medium. The carrier medium can be water, for example. The ground material can contain a proportion of a desired raw material. For example, the ground material can have an ore content. A major portion of the regrind can be deaf, ie lack the desired raw material. The crushing creates small particles that can be further processed in subsequent process steps. The proportion of particles with the desired raw material can be increased, for example, in a subsequent concentration step. For example, in the concentration step, a density difference between particles from the waste material and particles with the desired raw material can be used.

The vertical ball mill described herein can have a large filling volume of more than 20 m ³ . For economical pre-grinding of minerals, mills with a net volume (filling volume) of 20 m ³ to 150 m ³ are required in practice. To enable the high filling volume, the vertical ball mill is dimensioned accordingly and is therefore large and heavy. The speed of rotation of the grinding discs can be up to 15 m/s. The power of the drive motors can be up to around 12,500 kW.

The grinding bodies can have a spherical shape, for example. The grinding bodies can be made of a low-wear material. In particular, the grinding media can have a greater hardness than the ground material. The grinding media can consist, for example, of a metal material, in particular steel, or a ceramic material.

The grinding media, the material to be ground and the carrier medium are enclosed in a fluid-tight container. During operation, the container is immovably connected to a substrate. The container can thus be referred to as a stator. The grinding media are driven to move in the container by a driving element of the ball mill. The driving element can be referred to as a rotor. The grinding bodies can be moved in the stator on an approximately circular path without any appreciable upward and/or downward movement. The circular path can be perpendicular to a vertical main axis of the ball mill within an angular tolerance get lost. The angle tolerance can be referred to as position tolerance. The angular tolerance can be, for example, 10° or less, preferably 5° or less, particularly preferably 2° or less.

The material to be ground is ground or comminuted between the grinding bodies when grinding bodies of different speeds collide and/or roll off one another. A speed differential between the grinding media is achieved by moving the grinding media in close proximity to the rotor at approximately a moving speed of a surface of the rotor. Grinding media in the immediate vicinity of the stator, on the other hand, do not move at all. A speed profile of the grinding media develops between the rotor and the stator. The faster grinding media located closer to the rotor collide or rub against the slower grinding media located closer to the stator.

The rotor can be aligned with the main axis within the angular tolerance. The rotor can be rotatable about the main axis. The rotor can be overhung. The rotor can then be unsupported at a lower end. However, additional storage at the lower end need not be ruled out. The rotor can be held in a hanging orientation, i.e. essentially perpendicular to a base, by its own weight.

The stator can be open at the top. The rotor can dip essentially vertically from above into the carrier medium with the material to be ground and the grinding bodies. The rotor can be mounted independently of the stator. The stator can be spatially, statically and/or mechanically separated from the rotor or a rotor bearing of the rotor.

The stator has a lateral surface that is approximately cylindrical within a shape tolerance. In other words, the stator can enclose a cylindrical volume, in particular a circular-cylindrical volume. For this purpose, the stator can preferably have an approximately circular cross-sectional area within the shape tolerance and can therefore be rotationally symmetrical. The stator may also have an oval, triangular, octagonal, n-sided or generally polygonal cross-sectional area. The cross-sectional area may remain the same within a shape tolerance from a bottom edge of the stator to a top edge of the stator. The shape tolerance describes a permissible deviation from a cylindrical shape. The shape tolerance can be, for example, 10% or less, preferably 5% or less, particularly preferably 2% or less based on the overall dimensions of the stator. In other words, the stator can be out of round within the form tolerance.

A lateral surface describes an interface for the grinding bodies, the carrier medium and the material to be ground. The lateral surface can be represented by an inner surface of the stator. The lateral surface can be vertical or plumb within the angular tolerance.

A base plate transfers the weight of the stator, the grinding bodies, the carrier medium and the material to be ground completely or at least to a large extent into the foundation and is designed to withstand the load. The base plate can be firmly connected to the foundation. The baseplate may have a load bearing surface to interface with the stator. The load bearing surface may have a shape corresponding to the cross-sectional area of the stator within the shape tolerance. The base plate can be flat on one surface or on two opposite surfaces. The base plate may have an insert for reinforcement in the area of the load-bearing surface. The base plate can be made of a metal material. The base plate can be a separate component, for example, and can rest on the foundation. The base plate can also stand on support feet and be arranged at a distance from the foundation. Alternatively, the base plate can be designed as a specially shaped area of the foundation.

A stator segment can have an essentially arched basic shape. A wall of the stator segment forms a partial area of the lateral surface. The wall can represent an angular area of the lateral surface. If the stator has two stator segments, both walls can each form an angular range of 180°. With three stator segments, each wall can represent an angular range of 120°. With n>3 stator segments, each wall can represent an angular range of (360/n)°. The stator segments can be divided differently in the circumferential direction.

The wall has a wall thickness designed to withstand the load. In particular, the wall of the stator segment can be designed structurally, ie in particular due to its wall thickness and/or due to reinforcement measures, to be able to withstand the forces and loads that arise in the mill described, particularly where the stator segments stand up at the bottom.

The wall can be equipped with a protective layer on an inside to prevent direct contact between the grinding media and the wall. The wall can have stiffening ribs on the outside.

Side edges of the wall can be perpendicular to the top edge and/or bottom edge within the angle tolerance. A sealing surface can be aligned transversely to a pulling direction of connecting elements for connecting the stator segments. In the case of a tangential direction of pull, the sealing surface can be aligned radially. In the case of a radial direction of pull, the sealing surface can be oriented tangentially. The standing surface can be aligned transversely to an expected load direction. The stand can be aligned horizontally within the angle tolerance. The sealing surface and/or the standing surface can be formed by stiffening ribs arranged on the edges of the wall.

The stator segments are mobile or can be lifted off the base plate. A mechanical connection to the base plate can be released beforehand. Due to the mobility of the stator segments, the vertical ball mill can be opened easily. The rotor is easily accessible when the ball mill is open and maintenance work can be carried out easily on the inside of the stator segments.

On an inner side of the walls of the stator segments, a plurality of horizontal, ring-segment-shaped ribs spaced vertically apart can be arranged. The ribs may form inwardly projecting annular surfaces on the assembled stator, referred to herein as braking surfaces. The rotor may include a plurality of vertically spaced, horizontal disks each having an outer annular surface, referred to herein as a drag surface. The ribs and the discs may be alternately arranged in the vertical direction. An inner diameter of the braking surfaces can be smaller than an outer diameter of the drag surfaces. The braking surfaces and the drag surfaces can thus at least partially overlap in the horizontal direction. A meandering labyrinth can be formed between the ribs and disks. The labyrinth increases a flow resistance for the pulp through the ball mill. The ribs can therefore also be viewed as deflection surfaces. The ribs can be oriented perpendicular to the wall within angular tolerance. The discs can be aligned perpendicular to the rotor shaft within the angular tolerance. The disks can approximate a circular shape within shape tolerance. The discs can also be polygonal. Like the walls, the ribs or the braking surfaces can have a protective layer, for example to ensure direct contact with the grinding balls impede. The discs can also have a protective coating. The protective layer can be replaceable. The ribs, which form a common braking surface on the assembled stator, can be arranged at the same height on the stator segments and can have the same width or height. The ribs and disks may be evenly spaced. The discs can have openings between the drag surfaces and the rotor shaft. The drag surfaces on the rotor generally increase a contact surface of the carrier medium, the material to be ground and the grinding bodies with the rotor. The carrier medium, the material to be ground and the grinding bodies can be driven in an improved manner by the drag surfaces. A movement speed of a point on the discs increases in proportion to a distance of the point from the axis of rotation of the rotor. At the outer diameter of the rotor, the drag surfaces are moved with the highest movement speed. The braking surfaces on the stator increase the contact surface of the carrier medium, the material to be ground and the grinding bodies with the stator. The carrier medium, the material to be ground and the grinding bodies can be braked or driven in an improved manner by the braking surfaces or drag surfaces. During operation, there is a large difference in speed between the drag surfaces and the braking surfaces. This creates a large speed gradient in the carrier medium, the material to be ground and the grinding media, which leads to high speed differences between the individual grinding media. The high speed differences result in high impact and frictional forces and the ground material is efficiently shredded. A main grinding area of the vertical ball mill can be arranged between the drag surfaces and the braking surfaces.

The stator segments can each have stop elements on an outside for lifting and moving the respective stator segment. Attachment elements can be fixed points specially designed for attaching hoists. The stop elements can be dimensioned according to the load. The stop elements can be connected to the wall and/or the reinforcing ribs via a reinforcing structure. For example, the stop elements can be connected via additional ribs. The stop elements can be oversized for safety. Stop members may be specific to one type of hoist. For example, attachment pins for belts, ropes and chains and shackles can be used. Attachment eyes can be provided for hooks. Stop surfaces can be used to introduce compressive forces from lifting equipment.

The stator segments can each have stop elements in the area of the lower edge of the wall, which are configured in particular for attaching hydraulic jacks. For this purpose, the stop elements can have, for example, substantially horizontally aligned stop surfaces. The stop elements can also have a special interface geometry. For example, spherical or spherical cap-shaped surfaces on the stop element or lifting device can interact with balls or spherical caps on the lifting device or stop element in order to achieve angle-insensitive support.

The stop elements can define corner points of a virtual horizontal polygon, in particular a triangle, whose geometric center lies on a vertical axis through a center of gravity of the stationary stator segment. The geometric center of a triangle is at the intersection of the bisecting lines of the triangle. In a quadrilateral, the geometric center is at an intersection of the diagonals of the quadrilateral. A weight distribution between the stop elements can be predetermined by a position of the stop elements. By matching the axis through the center of gravity and the center point of the polygon, tilting stability when lifting a stator segment can be maximized.

The ball mill can have a displacement device for laterally displacing the stator segments that are separated from one another, the displacement device having mobile auxiliary devices which are designed to be arranged between the stop elements and parallel rails arranged on the floor when the stator segment is lifted and to be arranged with the To be moved along the rails stator segment. The rails can be firmly connected to the foundation. The auxiliary devices can have plain bearings or rolling bodies to reduce friction when moving. Rolling bodies can be rotatably mounted rollers, for example. The rollers themselves can be fitted with roller or plain bearings. With a plain bearing, the weight of the stator segment is distributed over a large area, which means that a low surface pressure can be achieved. The slide bearing can be lubricated via a lubrication system. Alternatively or additionally, a pair of materials between the sliding bearing and the rail can have a low coefficient of friction. For example, the plain bearing can have a sliding surface made of PTFE, POM or a similar material. The stator segment can be moved with the auxiliary devices using a moving device. The movement device can be arranged between the stator segment and a fixed point and tensile forces and/or compressive forces can be transmitted through the rails exert a defined direction of movement. The movement device can, for example, have at least one cable pull, chain pull or hydraulic cylinder.

The displacement device can have at least one tilting support for supporting a stop element, which is spaced vertically from the standing surface, on at least one of the rails in order to prevent the stator segment from tilting during lifting and displacement. An anti-tipper can support the stator segment at a relevant distance from the ground. For this purpose, the anti-tilt support can connect the rail to the higher-lying stop element at an oblique angle. The anti-tilt support can be mobile, that is to say it can be moved independently of the stator segment and only then be attached to the stator segment when the stator segment is to be moved.

Alternatively, the anti-tipper may be fixed to the stator segment and remain in place during operation. The anti-tipper can be connected to a lower stop element via a lower connection. The bottom connection can prevent the anti-tipper from deflecting sideways. The anti-tipper can also be used to align the vertical flanges. One of the stop elements for lifting the stator segment can be arranged on the anti-tipper. Two more of the stop elements for lifting can then be arranged on the lower edge of the wall, which are arranged essentially on a connecting line through the center of gravity of the stationary stator segment.

The stator segment can have at least one working platform. The work platform can be aligned horizontally within a position tolerance on the stationary stator segment. The working platform can run along an outer contour of the stator segment. The lowest work platform can be arranged at overhead height on the stator segment. At least standing height can be maintained as a vertical distance between higher work platforms. A ladder can be arranged on the anti-tipper, via which the work platform is accessible. The work platform and the ladder can have railings and/or fall protection devices. The stator segment can be easily accessible for maintenance work via the working platform. Thanks to the working platform, there is no need for mobile scaffolding during maintenance work.

The rails can be embedded in the foundation of the ball mill and can optionally be covered by covering devices when not in use. The rails can be concreted in, for example. The rails can be placed in recesses in the foundation. The covering devices protect the rails from dirt and damage. In particular, one surface of the rails can be protected from damage in this way. An upwardly directed surface of the rails or a covering device covering these rails may be flush with a surface of the foundation. The covering devices can be driven over. Thus, an environment of the vertical ball mill is kept accessible.

The ball mill can have an emptying device for emptying the ball mill. Since the grinding bodies remain in the ball mill during operation, the grinding bodies can be drained through the discharge device with residues of the carrier medium and the material to be ground before the stator is opened. The emptying device can be designed, for example, as a flap or slider in the wall of a stator segment.

The evacuation means may include a sloping floor within the load bearing surface of the base. One of the stator segments can have an emptying opening of the emptying device in the region of a low point of the sloping floor. A sloping floor allows the grinding media to flow off to the side, driven by gravity, when being emptied. The sloping floor has a slope from a lowest point to a highest point. The slope can be, for example, within an angular tolerance of between 1° and 5°, preferably between 2° and 3°, particularly preferably 2.5°. The inclined floor can be designed as an inclined plane. The sloping floor can also be designed as a three-dimensionally shaped surface aligned with the lowest point. The drain hole provides a through hole through the wall. The drain opening can be designed as a pipe connection. The pipe connection can be standardized, for example. The pipe connection can be designed with a size of DN 150, for example. The discharge opening can have a suitable fitting, such as a slide, a flap, a cock or a valve.

One of the stator segments can have at least one flushing opening of the emptying device in the area of a high point of the inclined floor. A flushing fluid, in particular a flushing liquid, can be conducted through the flushing opening into the interior of the stator in order to flush it out. The flushing opening can be designed as a pipe connection. The scavenging opening can, for example, have a standardized design. The flushing opening can be designed with a size of DN 100, for example. The Flush port may include any suitable fitting such as a gate, flapper, cock or valve. The flushing opening can be arranged opposite the emptying opening. Rinsing can help empty the ball mill. For example, liquid can be introduced through the flushing opening, which generates a flushing flow over the sloping floor.

The ball mill may have a stand separate from the stator. Supports of the frame may be supported on the ball mill foundation laterally spaced from the stator. At least one cross member of the frame can connect the supports to each other above the stator. A bearing device of the rotor can be supported on the cross member. In other words, a frame can be provided for the ball mill, which is designed separately from the stator and does not load on the stator, the bearing and drive arrangement being held and supported on a cross member of this frame, so that these components do not weigh on the stator . The frame can, for example, be composed of steel girders, in particular screwed. The frame can be designed as a portal under which the stator is arranged. Because of the frame, the stator can be dismantled without having to modify the rotor. The stator segments can be moved sideways away from the rotor for maintenance work, for example.

The ball mill can have a disengaging device for laterally disengaging the rotor, which can be uncoupled at an overhead clutch. The release device can have at least one rail and one coupling device. The coupling device can be designed to be connected to the rotor in the area of the coupling, to be lowered onto the rail with the rotor and to be moved along the rail with the rotor. A disengagement device can move the rotor to an accessible position for maintenance while the drive remains in place. The rotor can be separated from the drive at the clutch. The coupling can be screwed with several screws, for example. A stop member can be coupled to the clutch to lift the disengaged rotor with a crane. The coupling device can have a geometry adapted to a contour of the rotor in the area of the coupling. The coupling device can enclose the rotor shaft. The coupling device can have stop elements for attaching lifting gear. In particular, the stop elements can be designed for attaching hydraulic lifters. The rail can also have stop elements for attaching the hydraulic jack. In particular, the release device can have two rails which are arranged on both sides of the rotor shaft.

The frame can have a maintenance cabin in the area of the rotor coupling. The coupling can be accessible from the service cabin. The maintenance cabin can be used for the protected storage of tools. The maintenance cabin can protect the coupling from environmental influences.

It is noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments of the ball mill, the stator segment or the method of servicing the ball mill. A person skilled in the art will recognize that the features of the ball mill, the stator segment and the method can be combined, transferred, adapted and/or interchanged in a suitable manner in order to arrive at further embodiments of the invention.

Brief description of the drawings

• Fig. 1 zeigt eine räumliche Darstellung einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 2 zeigt eine räumliche Darstellung einer geöffneten vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 3 zeigt eine räumliche Darstellung eines Statorsegments einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 4 zeigt eine Schnittdarstellung durch eine vertikale Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 5 zeigt eine Schnittdarstellung durch eine vertikale Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 6 zeigt ein Ablaufdiagramm eines Verfahrens zum Warten einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 7 zeigt eine räumliche Darstellung einer geschlossenen vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 8 zeigt eine räumliche Darstellung einer geöffneten vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 9 zeigt eine räumliche Darstellung eines Statorsegments einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 10 zeigt eine räumliche Darstellung einer Arbeitsplattform einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 11 zeigt eine räumliche Darstellung einer Verlagerungseinrichtung einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel;
• Fig. 12 zeigt eine Detaildarstellung eines Standflanschs einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel; und
• Fig. 13 zeigt eine Detaildarstellung eines Dichtflanschs einer vertikalen Kugelmühle gemäß einem Ausführungsbeispiel.

Embodiments of the invention are described below with reference to the accompanying drawings, neither the drawings nor the description being to be construed as limiting the invention.

• 1 shows a spatial representation of a vertical ball mill according to an embodiment;
• 2 shows a spatial representation of an open vertical ball mill according to an embodiment;
• 3 shows a spatial representation of a stator segment of a vertical ball mill according to an embodiment;
• 4 shows a sectional view through a vertical ball mill according to an embodiment;
• figure 5 shows a sectional view through a vertical ball mill according to an embodiment;
• 6 FIG. 12 shows a flow chart of a method for servicing a vertical ball mill according to an embodiment; FIG.
• 7 shows a spatial representation of a closed vertical ball mill according to an embodiment;
• 8 shows a spatial representation of an open vertical ball mill according to an embodiment;
• 9 shows a spatial representation of a stator segment of a vertical ball mill according to an embodiment;
• 10 shows a spatial representation of a work platform of a vertical ball mill according to an embodiment;
• 11 shows a spatial representation of a displacement device of a vertical ball mill according to an embodiment;
• 12 shows a detailed view of a stand flange of a vertical ball mill according to an embodiment; and
• 13 shows a detailed view of a sealing flange of a vertical ball mill according to an embodiment.

The figures are merely schematic and not true to scale. In the figures, the same reference symbols denote the same features or features that have the same effect.

Embodiments of the invention

1 shows a spatial representation of a vertical ball mill 100 according to an embodiment. In the ball mill 100, with a filling volume of more than 12 m ³ to around 150 m ³ , it is very large and, in a continuous grinding process, a suspension of coarsely crushed material to be ground in a liquid carrier medium can be produced by moving grinding bodies with an average initial grain size by a factor of around 10 to 100 be crushed to an average target grain size. The grinding media can in particular be metallic and/or ceramic balls with a diameter that is approximately 2 to 50 times larger than the initial grain size. The initial grain size here can be up to 15 millimeters. The grinding bodies can be between 5 millimeters and 50 millimeters in size. The ball mill 100 can thus be used as a comminution stage in a multi-stage digestion process, for example in the extraction of raw materials. There, the grist may contain desired minerals and waste rock to be separated.

The ball mill 100 has an overhead rotor for moving the media. A free-standing stator 102, as a container for the suspension and the grinding bodies, radially encloses a working space of the ball mill 100 and the rotor. A working space inside the stator 102 of the ball mill 100 shown here is between 12 cubic meters and 150 cubic meters. During operation, the working space is mostly filled with a grinding media bed made up of many grinding media. The suspension with the coarsely crushed material to be ground is fed continuously into the bed of grinding media in a lower area of the working space at a flow rate of between 50 cubic meters per hour and 5000 cubic meters per hour. The ground material is comminuted as it flows through the grinding media bed. In an upper region of the working space, the suspension with the comminuted material to be ground flows out of the bed of grinding media and is discharged from the working space, while the grinding media remain in the working space.

A shear flow forms between the stator 102 and the rotor during the grinding process when the rotor is rotating, since a rotor boundary layer of the suspension surrounding the rotor with the grinding media contained therein is entrained by the rotor essentially at an angular velocity of the rotor and a stator boundary layer of the suspension with the is held substantially stationary on the stator 102 by the grinding media contained therein. Between the rotor boundary layer and the stator boundary layer, a speed profile of the shearing flow develops, since the suspension and the grinding media are moved faster the closer they are to the rotor. Due to the course of the speed, there are mass collisions between fast and slow grinding bodies, in which the material to be ground in between is crushed. The comminuted material to be ground is swept upwards in the working chamber by an upward flow of the carrier medium resulting from the flow of the suspension through the bed of grinding media.

The stator 102 has a lateral surface 104 that essentially approximates the shape of a cylinder and, in the representation shown in the figure, covers the rotor. The rotor is mounted axially and radially above the stator 102 at an upper end and hangs into the working space. A bearing and drive device 106 of the rotor is supported directly on a foundation 110 of the ball mill 100 via a free-standing frame 108 . The storage and drive device 106 has four electric motors 107 with a total output of between 0.8 megawatts and 12.5 megawatts, which drive the rotor via a common gearbox. Fewer or at least one electric motor can also be used. There is no load bearing contact between the frame 108 and the stator 102 . A drive torque of the bearing and drive device 106 is derived via the frame 108 into the foundation 110 . The stator 102 stands self-supporting on a base plate of the ball mill 100. The base plate supports a weight of the stator 102, a counter torque of the driving torque, and a weight of the grinding media, the minerals, and the carrier medium on the foundation 110. The base plate is in 1 covered by the stator 102.

The stator 102 can be divided in particular for maintenance purposes. Here the stator 102 is composed of two essentially identical stator segments 112 . The stator 102 can also be composed of more than two stator segments 112 . The stator segments 112 are connected to one another via sealing flanges 114 . The sealing flanges 114 run from an upper edge of the stator 102 to a lower edge of the stator along side edges of a wall 116 of the stator segments 112. To connect the stator segments 112, the sealing flanges 114 can be screwed together, for example. To separate the stator segments 112, the screws can be loosened again. Alternatively, the adjacent stator segments 112 can also be mechanically detachably connected to one another in some other way. The sealing flanges 114 form sealing surfaces 118 for fluid-tight sealing of the working space. Additional seals can be arranged between sealing surfaces 118 . The sealing surfaces 118 or seals prevent the suspension from escaping at the separation points of the stator 102. Sealing flanges 114 can also be provided with leakage channels. Leakage channels can divert any escaping carrier medium to a collection system. The wall 116 of a stator segment 112 forms a segment of the lateral surface 104 of the stator 102 that approximates the shape of a segment of a cylinder and is reinforced on an outside by a plurality of tangentially aligned stiffening ribs 117 . In addition, the wall 116 is reinforced on the outside by a few stiffening ribs 119 running in the axial direction. The sealing flanges 114 essentially correspond to axial stiffening ribs 119 running along the side edges. The stiffening ribs 117, 119 stiffen the stator 112, among other things, against hydrostatic pressure from the carrier medium.

The stator segments 112 each have a peripheral standing flange 120 on the lower edge. The standing flange 120 is essentially one along the bottom edge of the Walls 116 running tangential rib. The stator segments 112 are connected to the baseplate via the standing flanges 120, in particular in such a way that forces due to the weight of the stator segments 112 and possibly due to the weight of the grinding bodies and the material to be ground can be dissipated into the baseplate. For example, the standing flanges 120 can be screwed to the base plate. The standing flanges 120 form a standing surface 122 of the stator 102 that is dimensioned appropriately for the load. The entire weight of the stator 102 is supported on the base plate via the base 122 . The standing surface 122 is also a sealing surface 118 and seals against the base plate. A seal can also be arranged between the standing surface 122 and the base plate. Leakage channels can also be formed between the standing surface 122 and the base plate.

In order to access the rotor, the working area can be emptied, i.e. the material to be ground and the grinding media removed. Then the stator segments 112 can be moved laterally. Before moving, a mechanical connection between the stator segments 112 and between the stator segments 112 and the base plate is released. Subsequently, the stator segments 112 can be individually lifted by means of a lifting device in order to be moved laterally free of the base plate. Hydraulic jacks, for example, can be used as the lifting device. Each stator segment 112 has a plurality of stop elements 124 for lifting. The stop elements 124 are arranged in the area of the lower edge of the wall 116 . The stop elements 124 are designed here as consoles that protrude beyond the standing surface 122 and have stop surfaces pointing downwards.

In one exemplary embodiment, the ball mill 100 has a displacement device 126 . The displacement device 126 has three sliding paths 128 per stator segment 112, via which the stator segment 112 can be moved away from the other stator segment 112 in a laterally guided manner. The sliding paths 128 are defined here by rails 130 anchored in the foundation 110 . The rails 130 and foundation 110 are designed to securely support the weight of a stator segment 112 . For shifting, the lifted stator segment 112 is lowered onto auxiliary equipment using the lifting device. The auxiliary devices are arranged between the stop elements 124 and the rails 130 and support the weight of the stator segment 112 lowered thereon via the rails 130 . The auxiliary devices maintain a distance between the standing surface 122 and the base plate, even when it is lowered again. The stator segment 112 is moved along the sliding path 128 with the auxiliary devices.

In one embodiment, the auxiliary devices are designed as sliding shoes, which slide on a surface of the rails 130 by means of a sliding coating and an optional lubricant. Pull systems and/or push systems may be used to move the stator segment 112 along the rails 130 .

In an alternative exemplary embodiment, heavy-duty rollers are arranged between the stop elements 124 and the foundation 110 , which is dimensioned appropriately for the load, in order to move the stator segment 112 , via which rollers the weight of the stator segment 112 is supported directly on the foundation 110 . The stator segment 112 can be moved freely on the heavy-duty rollers.

In one exemplary embodiment, at least one anti-tilt support 132 is arranged on at least one of the stator segments 112 . The anti-tilt support 132 can be firmly attached to the stator segment 112 or, alternatively, can be attached to stop elements 124 of the stator segments 112 provided for this purpose before the displacement. The anti-tipper 132 can be supported on the foundation 110 via a heavy-duty roller. Alternatively, the anti-tipper 132 can be part of the displacement device 126 . The anti-tilt support 132 is then coupled to one of the rails 130 by means of a further auxiliary device 134 . The additional auxiliary device 134 can be designed as a sliding shoe. The additional auxiliary device 134 can be secured against being lifted off the rail 130 . For this purpose, the auxiliary device 134 can at least partially encompass the rail 130 . In this way, the auxiliary device 134 can introduce compressive and tensile forces into the rail 130 . In addition, the anti-tilt support 132 is adjustable in length in order to be able to compensate for the stroke when raising and lowering the stator segment 112 or to correct an angular position of the stator segment 112 in relation to the other stator segment 112 .

In the exemplary embodiment shown, the rails 130 are arranged in depressions in the foundation 110 . Thus, the rails 130 can be covered during the operation of the ball mill 100, which protects them from damage and dirt better than if they were exposed.

2 shows a spatial representation of an open vertical ball mill 100 according to an embodiment. The ball mill 100 essentially corresponds to the ball mill in 1 . In contrast to the representation in 1 the stator segments 112 have been separated from one another here. The stator segments 112 were lifted at the stop elements 124 and thereby lifted off the base plate 200. Auxiliary devices 134 have been arranged between the stop elements 124 and the rails 130, on which the stator segments 112 have been placed. As a result, the standing areas 122 are at a distance from a load-bearing surface 201 of the base plate 200. Using a pulling device 202, the stator segments 112 on the auxiliary devices 134 are laterally shifted away from the base plate 200 along the sliding path 128 defined by the rails 130 in order to carry out maintenance work to be able to perform on the rotor 204 and/or an inner side 206 of the stator 102 . In the example shown, the stator segments 112 have been moved in opposite directions.

On the inner sides 206 of the walls 116, the stator segments 112 can have a plurality of vertically spaced, horizontal, ring-segment-shaped ribs 208. The ribs 208 of both stator segments 112 can be arranged in the same way. Flat sides of each rib 208 act as annular braking surfaces 210 for the suspension during operation of the vertical ball mill 100 . The ribs 208 also act as deflection surfaces in the direction of the rotor 204 for the suspension flowing from bottom to top through the ball mill 100. The ribs 208 are uniformly spaced. The ribs 208 on the inside 206 may, but need not, have a greater height and/or greater vertical spacing than the tangential stiffening ribs 117 on the outside. It is also possible to design the mill cylinder without internal ribs.

The rotor 204 is shown separated from the drive and bearing assembly 106 and laterally disengaged. The rotor 204 has a plurality of discs 212 which are arranged on a rotor shaft 205 and are vertically spaced apart and aligned transversely to the rotor shaft 205 . On its flat sides, each disc 212 has two annular drag surfaces 214 for driving the suspension. The discs 212 have openings 213 towards the rotor shaft 205 . Spokes 215 are formed between the drag surfaces 214 and the rotor shaft 205 through the openings 213 .

When the ball mill 100 is ready for operation, the ribs 208 and the disks 212 can be spaced apart from one another and arranged alternately one above the other in the working space, with the braking surfaces 210 and the drag surfaces 214 being able to overlap at least partially in the horizontal direction. Due to the overlapping of the ribs 208 and the discs 212, a labyrinth is formed between the stator 102 and the rotor 204 in the operational state, which forms a flow path for the suspension extended by the ball mill 100. An embodiment without the inner ribs 208 is also feasible. At an upper end, the rotor 204 has a coupling 216 via which the rotor 204 can be detachably coupled to the bearing and drive device 106 .

The frame 108 has a disengagement device 218 for disengaging the rotor 204 . The release device 218 has two rails 130 which are connected to the frame 108 and protrude laterally over the crossbeam of the frame 108 and a coupling device 220 . The rails 130 are arranged on opposite sides of the rotor shaft 205 .

To disengage, the coupling device 220 is connected in the area of the clutch 216 to the rotor 204 coupled to the bearing and drive device 106 . The coupling device 220 is essentially U-shaped and is pushed onto the rotor shaft 205 from the side. An open end of the coupling device 220 is then closed by a latch 222 . The coupling 216 has a larger diameter than the rotor shaft 205. The coupling device 220 is raised until it rests against the coupling 216 and the bearing and drive device 106 is relieved by the weight of the rotor 204 being intercepted by the coupling device 220. Then the clutch 116 is released from the bearing and drive device 106 . The coupler 220 with the rotor 204 detached is then lowered until it rests on the rails 130 . The rotor 204 together with the coupling device 220 is then moved along the rails 130 until the coupling 216 is arranged next to the cross member and is accessible from above. The coupling 216 can then be lifted out of the coupling device 220 using an adapter with a crane. The coupling device 220 can have a sliding coating, for example.

Below are details of the embodiment as shown in 1 and 2 is shown, explained in more detail and with partially modified choice of words.

The figures 1 and 2 show a ball mill 100 in which a mill drive consisting of motor(s) 107 and gearing serving as a bearing and drive device 106, together with a mill shaft serving as a rotor shaft 205, are arranged at the top of the vertical mill on a platform or a mill frame, which serve as a frame 108 is. The mill shaft carries grinding discs 212 and together with these can be referred to as rotor 204 . The platform at the top of the mill only supports the weight of the rotor, motor and gearbox, resulting in relatively small forces. The Forces are particularly small compared to the acting forces when the whole mill is suspended above.

A grinding cylinder of the ball mill 100 acting as a stator 102 with an anti-wear lining and stationary discs in the form of ribs 208 is not structurally connected to the mill drive. The grinding cylinder can be divided into two grinding cylinder halves with stationary disks. A hollow seal is used to seal the vertical flange and the radial flange. A weight of the grinding cylinder, the stationary discs, grinding bodies and the suspension of grinding material and carrier medium, referred to here as pulp, is carried by the anchoring on the ground and diverted into the foundation. The grinding cylinder construction is sufficiently stable to absorb the forces. The base plate 200 is anchored in the concrete on the floor to absorb and dissipate the grinding cylinder forces. An optional wear plate protects the base plate 200 and is supported solely by its own weight or can also be mechanically attached and can be easily removed. A slurry inlet is sideways down and a slurry outlet is sideways up.

During operation of the ball mill 100, the interior of the grinding cylinder or the mill cylinder is filled with grinding beads (not shown) up to 80% of the height of the grinding cylinder. There is turbidity in the spaces between the grinding beads and above the bed of grinding beads. Here, the ball mill 100 is emptied through openings on the mill floor.

The vertical ball mill 100 presented here can be used in particular for primary grinding, ie for coarse grinding. Here, regrind with a maximum grain size F100 of 10 mm to 15 mm or with an F80 of 250 microns to 5 mm is ground economically to a fineness of P80 of 100 µm.

A variant of the ball mill 100 can be used for fine comminution. A grinding to a product fineness with a P80 of 40 to 300 µm is referred to here as a fine range. In the fine range, the feed fineness is preferably in the range of less than 500 μm.

In the case of the vertical ball mill 100 presented here, the grinding bodies essentially remain in position in the vertical direction. Essentially no lifting work is applied. The grinding takes place in the areas between the Rotor disks 212 and the housing disks formed by the ribs 208. The grinding chamber, and thus the stress on the material to be ground with the grinding media, is very well defined. This increases grinding efficiency. The grinding forces required for grinding are essentially generated by centrifugal forces. Gravity causes a top-to-bottom contact force or squeeze between the grinding media and a top-to-bottom increasing hydrostatic pressure in the stator 102. The grinding forces can be influenced and changed by the speed and mass of the grinding media. The ground material is transported in the vertical ball mill 100 by the drag forces in the pulp which are generated by the feed pump. The residence time and thus the energy input can be influenced by an adjustable delivery rate of the feed pump. The finished product is transported through the openings in the rotor and discharged from the top of the mill in the overflow. A separate external view circuit is generally not required. However, one can be provided if necessary.

The fine material from the vertical ball mill 100 presented here achieves a narrow grain size distribution (PSR) that is advantageous for the subsequent treatment stage (flotation, leaching). This corresponds to a steep course of a delicacy curve shown in the RRRS diagram. A narrow particle size distribution is achieved by minimizing over-grinding. In the approach presented here, the already finished product is removed from the grinding process as quickly as possible. The better this succeeds, the steeper the price-earnings ratio. The grinding chamber of the vertical ball mill 100 is therefore designed in such a way that these requirements are met. This is essentially achieved by openings in the form of openings 213 in rotor disks 212 . A pump conveys the slurry from bottom to top, passes through the openings and the grinding chamber and takes the fines of the ground material with it. The speed is determined by the flow rate of the pump. The flow rate is adjusted in such a way that the product ground to the desired product fineness is transported away and coarser material remains in the grinding chamber of the mill. The material to be ground, which has already reached the required fineness, is removed from the grinding chamber as quickly as possible. This avoids over-grinding.

Before maintenance work can begin on the ball mill 100, the interior of the grinding cylinder is emptied. The grinding beads and the slurry are drained through openings and pipes in the mill floor and by opening the relevant valves. Due to their own weight, the grinding beads and the slurry leave the grinding chamber through the floor openings. The drain volume can be adjusted through the valves regulated and supported by rotation of the rotor. Pipelines lead the grinding beads and the pulp to a suitable conveyor system, which is installed below the mill floor. The conveying system can be, for example, a conveyor belt, a screw conveyor, a pump or a bucket elevator. The list is not final.

The conveyor system transports the milling beads and slurry sideways of the ball mill 100 to a level high enough to be loaded into a bin or truck. This process is continued until the ball mill 100 is completely empty.

To open the stator 102 by moving one of the stator segments 112 in the form of the first grinding cylinder half, the slide rails 130 are covered and cleaned. In this case, in particular, a slide rail surface is cleaned. Subsequently, assembly supports or anti-tipping supports 132 are mounted on both halves of the mill cylinder and screwed pipe flange connections of the pulp feed and the pulp discharge pipe are loosened. Then the vertical and radial flange screws are loosened and three hydraulic cylinders are pushed in for each half of the grinding cylinder. Using the three hydraulic cylinders, one half of the grinding cylinder is raised by approx. 25mm and three Teflon shoes are attached to the half of the grinding cylinder and another shoe to the assembly support. The grinding cylinder half is lowered with the three hydraulic cylinders until the Teflon sliding shoes stand up on the slide rails. Then the pull and push cylinders on both sides are connected to the tabs provided on the grinding cylinder or the sliding shoes. The assembly support is extended with its hydraulic cylinder until the grinding cylinder half begins to lift. With the two pull and push cylinders, the grinding cylinder half is pulled to the intended maintenance position.

To dismantle the mill shaft, a shaft assembly slide or shaft assembly carriage is moved to the installed shaft as a disengaging device 218 . The shaft assembly carriage is lifted about 25mm upwards with four hydraulic cylinders and the shaft clamp is closed and clamped around the shaft shaft. Then the coupling screws are loosened. The shaft assembly carriage is lowered together with the clamped and decoupled shaft using four hydraulic cylinders until the shaft assembly carriage touches the slideway. With at least one hydraulic traversing cylinder, the shaft assembly carriage with the shaft is moved to a lateral position or a Lifting position, at which the shaft can be lifted with the indoor crane, shifted. There, a shaft holding device or an eyelet is installed on the shaft coupling. Now the shaft can be lifted off the hook of the indoor crane. The shaft can be stored in a hanging fixture or placed on a dedicated maintenance trailer.

3 shows a spatial representation of a stator segment 112 of a vertical ball mill according to an embodiment. The stator segment 112 essentially corresponds to one of the stator segments 112 in FIGS figures 1 and 2 . Contrary to what is shown in the figures 1 and 2 the stator is composed of three stator segments 112 in the exemplary embodiment shown. The wall 116 forms an arc of 120°. The sealing flange 114 and the sealing surface 118 as well as the base flange 120 and the base 122 are provided with through holes 121 in order to screw them to a correspondingly designed counterpart, i.e. another sealing surface of another stator segment 112 or the load-bearing surface of the base plate. The stator segment 112 shown here has a weight of approximately 30 tons. On the inside 116 nine rib segments are arranged one above the other at regular intervals.

The stop elements 124 designed as consoles protrude radially beyond the standing surface 122 and are connected to the wall 116 via two axially aligned stiffening ribs. Two of the stop elements 124 are arranged in the area of the lower corners of the wall 116 .

4 shows a sectional view through a vertical ball mill 100 according to an embodiment. The ball mill 100 essentially corresponds to that in FIGS figures 1 and 2 ball mill shown. The ball mill 100 has an emptying device 400 for emptying the working space. The base plate 200 of the ball mill 100 has a sloping floor 402 as part of the emptying device 400 . For sloping floor 402, a surface enclosed by the load bearing surface 201 supporting the weight of the stator segments 112 is raised above surface 201 and slanted at an angle of approximately 2.5° to 30° from horizontal.

One of the stator segments 112 has a drain opening 404 in the region of a low point of the sloping floor 402, ie where a surface of the sloping floor 402 is closest to the load-bearing surface 201. Drain port 404 is here designed as a radially aligned pipe connection flange. In operation, the drain opening 404 is closed by a suitable fitting. The valve is opened for emptying. In addition to the ball mill 100, the foundation 110 has a pit 406 in the area in front of the discharge opening 404, in which transport containers for transporting away the grinding bodies can be placed in order to empty the working space. Through the discharge opening 404, the grinding bodies with adhering residues of the suspension can be discharged into the transport containers arranged in the pit 406, driven by gravity. During the purge, the rotor 204 may be driven to eject media deposited on the disks 212 to the outside.

In one exemplary embodiment, the other stator segment 112 has at least one flushing opening 408 in the region of a high point of the sloping floor 402, ie where the surface of the sloping floor 402 projects farthest beyond the load-bearing surface 201. The flushing opening 408 is also designed here as a radially aligned pipe connection flange. The flushing port 408 is located diametrically opposite the drain port. The flushing opening 408 can support the emptying of the working chamber by means of a liquid flow directed onto the emptying opening 404 . The flushing opening 408 is also closed by a suitable fitting during operation.

In addition to the upper radial and axial bearing in the bearing and drive device 106, the rotor 204 can also be mounted in the base plate 200 via a radial floating bearing. For this purpose, the rotor shaft has a bearing journal at the lower end, which is mounted in the movable bearing. Changes in the length of the rotor 204 can be compensated for by shifting the floating bearing on the bearing journal.

figure 5 shows a sectional view through a vertical ball mill 100 according to an embodiment. The ball mill 100 essentially corresponds to the ball mill in 4 . In contrast, here the base plate 200 covers the pit 406 at least partially. The base plate 200 has the at least one emptying opening 404 here. If the fitting is opened, the contents of the working space flow out through the drain opening 404 .

In one embodiment, the base plate 200 has a plurality of drainage openings 404 . The drain openings 404 are distributed over the base plate 200 arranged. The multiple purge ports 404 together have an increased total cross-sectional area, thereby purging is rapid.

In one exemplary embodiment, a transport system 500 for conveying the contents of the workspace out of the pit 406 is arranged in the pit 406 . For example, the conveyor system 500 can be designed as a conveyor belt or screw conveyor. The transport system 500 has a delivery head that is sufficient to transport the contents into transport containers parked at ground level. However, the transport container can also be arranged under the mill so that no conveying device is required.

6 6 shows a flow diagram of a method 600 for servicing a vertical ball mill according to an embodiment. Using method 600, a ball mill configured specifically for pre-milling minerals may be serviced. The method 600 comprises a step 602 of separating, a step 606 of arranging and a step 610 of relocating.

The vertical ball mill has a downwardly hanging rotor which is supported axially and radially at an upper end. Furthermore, the vertical ball mill has a self-supporting stator which radially encloses the rotor and is unloaded by the weight of the rotor. The rotor has a lateral surface which is oriented tangentially to the rotor and approximates a cylindrical shape within a shape tolerance. Further, the vertical ball mill has a base plate that supports a weight of the stator. The stator is composed of at least two stator segments which can be separated from one another and are cantilevered in the separate state and can be displaced relative to one another. Each of the stator segments has, on at least one side edge of the wall running from an upper edge of a wall forming the lateral surface to a lower edge of the wall, a sealing surface for sealing on the respective other stator segment. Furthermore, each of the stator segments has on the lower edge a footprint dimensioned appropriately for the load for sealing to the base plate. The stator segment loads with the base orthogonally standing on a load-bearing surface of the base plate within an angular tolerance.

In step 602 of separating, the stator is separated into the stator segments, with the stator being separated at the sealing surfaces. Mechanical connections between adjacent stator segments can be released for this purpose.

In step 606 of placing, auxiliary devices are placed under the stator segment. The auxiliary devices can be positioned and configured in such a way that the entire stator segment can bear a load on the auxiliary devices and can be displaced with them.

In step 610 of shifting, the stator segment and the auxiliary devices are shifted laterally using a shifting device. At least one of the stator segments is in this case displaced essentially horizontally, while its weight preferably still weighs on the foundation of the ball mill via the auxiliary devices.

The ball mill with the stator opened in the manner described can then be easily serviced. In particular, the working space is easily accessible so that it can be cleaned and/or wearing parts can be replaced.

In one embodiment, the method 600 includes a step 604 of lifting and a step 608 of setting down. In the lifting step 604, at least one of the stator segments is lifted using lifting devices, whereby the stator segment is lifted off the base plate. Raising the stator segment by a few millimeters or a few centimeters can suffice. The lifting can be done in particular with the help of hydraulic lifting devices, which support stop elements on the respective stator segment from below. In step 608 of setting down, the stator segment is set down on the auxiliaries.

The design of the stator of the ball mill described here, which stands on the base plate and thus indirectly weighs on the foundation, thus makes it possible for the stator to be opened easily and preferably also by less trained personnel and/or under adverse conditions, in order to then service the ball mill to be able to With the configuration described above, maintenance can be performed in a shorter period of time. Since the mill can then be used again more quickly in the production process, productivity is increased.

7 shows a spatial representation of a closed vertical ball mill 100 according to an embodiment. The ball mill 100 essentially corresponds to the ball mill in 1 . In addition to this, the ball mill 100 on the frame 108 and on the stator 102 has working platforms 700 in several tiers one above the other. The work platforms 700 are secured all around by railings. The Stator segments 112 and the frame 108 have work platforms 700 on two floors. The frame 108 also includes work platforms 700 on two floors above. The ball mill 100 thus extends over four floors.

The work platforms 700 of a stator segment 112 are connected to one another via a ladder 702 . The ladder 702 is attached to the anti-tipper 132, which is permanently installed here. The ladder 702 has a safety cage. The anti-tilt support 132 is connected to both work platforms 700 or to a support structure of the work platforms 700 and is aligned essentially parallel to the longitudinal axis of the stator 102 . The anti-tipper 132 is spaced apart from the stator segment 112 by the work platforms 132 . Due to the permanently installed anti-tilt support 132 , the stator 102 has only two stop elements 124 in the area of the sealing flanges 114 . The third stop element 124 is arranged at the lower end of the anti-tilt support 132 . The sealing flanges 114 are easily accessible for maintenance work over their full length via the work platforms 700 of the stator 102 .

The work platforms 700 on the frame 108 are accessible via a stair tower 704 . The stair tower is located next to the frame 108. On the third floor, the frame 108 has a maintenance cabin 706 from which protected access to the coupling between the bearing and drive device 106 and the rotor and the release device is possible. The maintenance cabin 706 is surrounded by work platforms 700 all around. The work platform 700 of the fourth floor is essentially arranged on a roof area of the maintenance cabin 706 and extends around the storage and drive device 106 . The storage and drive device 106 has a single electric motor 107 here.

The frame 108 is designed as a framework construction. The frame 108 on the side of the stair tower 704 is designed as a three-dimensional framework and has six uprights in two parallel rows. On the lower two floors of the frame 108 work platforms 700 are arranged on the beams of the truss connecting the uprights. The work platforms 700 of the stator are also accessible from the work platforms 700 of the frame 108 when the ball mill 100 is in the closed state. On the side opposite the stair tower 704, the frame 108 is designed as a flat truss with three uprights in a row.

8 shows a spatial representation of an open vertical ball mill 100 according to an embodiment. The ball mill 100 corresponds to im Essentially the ball mill in 7 . The rotor is not shown here for reasons of clarity. Here, the stator segments 112 are shown separated from one another and shifted laterally. Contrary to what is shown in the Figures 1 to 6 the base plate 200 is here raised above a surrounding floor area. The sloping bottom 402 is designed as a sloping end face of a truncated cylinder that protrudes beyond the load-bearing surface 201, ie protrudes into the interior of the stator 102 when the ball mill 100 is closed.

The auxiliary devices 134 each have a frame 800 which connects all three stop elements 124 of a stator segment 112 and fixes their relative positions. On the frame 800, the auxiliary devices 134 can simply be lifted, for example with an indoor crane, and moved to a storage location. After separating the stator segments 112 , the stator segments 112 have been lifted at the stop elements 124 in order to detach them from the base plate 200 . The auxiliary devices 134 with their frame 800 have been arranged between the stop elements 124 and the displacement device 126 . The stator segments 112 have then been lowered onto the auxiliaries 134 . The auxiliary devices 134 have their own drive 802 . Using the drive 802, the auxiliary devices 134 with the stator segments 112 mounted thereon have been moved laterally along the displacement device 126 into the maintenance positions.

9 shows a spatial representation of a stator segment 112 of a vertical ball mill according to an embodiment. The stator segment 112 essentially corresponds to one of the stator segments in FIG figures 7 and 8th . The stator segment 112 has in contrast to the stator segments in the Figures 1 to 5 only one stiffening rib 117 on the outside. The stiffening rib 117 is arranged in a lower area of the lateral surface 104 above the axial stiffening ribs 119 of the stop elements 124 .

The work platforms 700 run all the way around the lateral surface 104 . On an inside, that is to say on a side facing lateral surface 104 , work platforms 700 have a cutout in the shape of a semicircular arc for stator segment 112 . The working platforms 700 are angular on an outside, ie on a side facing away from the lateral surface 104 . The working platforms 700 have the railing and a coaming 900 along all outer edges. The coaming 900 stands upwards over a floor surface of the work platforms 700 and prevents objects from falling.

The work platforms 700 have a cutout in the area of the sealing flange 114 . The sealing flange 114 is therefore not interrupted by the work platforms 700 . In the area of the cutout, the working platforms 700 on one side of the stator segment 112 extend beyond a plane of the sealing surface 118 or the sealing flange 114 . As a result, the sealing flange 114 is accessible from both sides and the stator segment 112 can be connected to the other stator segment, not shown here, in an ergonomic working position.

The ladder 702 is arranged on one side of the anti-tilt support 132 and has a passage through the safety cage at the level of the two work platforms 700 . The railing is interrupted in the area of the hatches.

10 shows a spatial representation of a work platform 700 of a vertical ball mill according to an embodiment. The work platform 700 essentially corresponds to one of the work platforms in 7 . The work platform 700 is rectangular. The working platform 700 has two outer sides like the working platforms in 9 a coaming 900 projecting beyond the floor area and a railing. The work platform 700 has a support structure below the floor surface. In particular, the bottom surface is reinforced by ribs. The ribs have attachment holes on two inner sides of the work platform 700 for attaching the work platform 700 to the ball mill.

At each of the four corners, the working platform 700 has a lifting bracket 1000 sunk into the floor area. The working platform 700 can be quickly and easily assembled and disassembled with the indoor crane using the lifting brackets 1000.

11 shows a spatial representation of a displacement device 126 of a vertical ball mill 100 according to an embodiment. The displacement device 126 essentially corresponds to the displacement device in FIG 8 . The displacement device 126 is placed on the rails 130 . The auxiliary devices 134 are arranged between the stop elements 124 and the rails 130 . The frame 800 is essentially V-shaped and connects the auxiliary devices 134 arranged on the stop elements 124 commonality. The two auxiliary devices 134 arranged on the stator segment 112 each have an electric drive 802 .

12 shows a detailed illustration of a stand flange 120 of a vertical ball mill 100 according to an exemplary embodiment. The stand flange 120 rests on the base plate 200. The base plate 200 corresponds to the representation in FIG 8 . The base flange 120 and the load bearing surface 201 have grooves 1200 arranged in a uniform grid. The slots 1200 in the load-bearing surface 201 are designed as T-slots in order to accommodate T-slot screws (not shown here) for screwing the stator 102 to the base plate 200 . When loosened, the T-slot screws can be removed from the side of the T-slots and the slots 1200 of the stationary flange 120 and thus do not represent an obstacle when the stator segments 112 are moved sideways.

13 shows a detailed view of a sealing flange 114 of a vertical ball mill 100 according to an embodiment. The ball mill 100 is closed here. The sealing flanges 114 of the stator segments 112 connected to one another are pressed together here by pivotable clamps 1300 . The clamps 1300 have an essentially U-shaped base body 1302 and enclose both sealing flanges 114 from the outside. On one of the stator segments 112, hinges 1304 are arranged on the outside, on which the clamps 1300 are mounted in a horizontally pivotable manner. The base bodies 1302 each have at least one threaded bore 1306 in which a screw spindle 1308 for pressing the sealing flanges 114 together is rotatably mounted.

In one exemplary embodiment, the sealing flanges 114 are connected to one another by pivotable clamping jaws 1310 . The clamping jaws 1310 are mounted on the hinges 1304 so that they can be pivoted horizontally. The jaws 1310 have a tapered, vertical slot 1312 on. The slot 1312 is wider at its wider end than both sealing flanges 114 together. At the narrower end, the slot 1312 is narrower than the sealing flanges 114. The sealing flanges 114 are inserted into the slot 1312 as the jaws 1310 pivot. When the side surfaces of the slot 1312 abut the sealing flanges 114, the clamping jaw 1310 can be wedged on the sealing flanges 114, for example by hammer blows. To release a clamping jaw 1310, for example, a wedge can be driven between the clamping jaws 1310 and the lateral surface 104 in order to push the clamping jaws 1310 off the sealing flanges 114.

Finally, it should be noted that terms such as "comprising,""comprising," etc. do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Any reference signs in the claims should not be construed as limiting.

Reference list:

100

ball mill

102

stator

104

lateral surface

106

Storage and drive equipment

107

electric motors

108

frame

110

foundation

112

stator segment

114

sealing flange

116

Wall

117

tangential stiffening ribs

118

sealing surface

119

axial stiffening ribs

120

stand flange

121

through holes

122

floor space

124

stop element

126

relocation facility

128

sliding distance

130

rail

132

Anti-tipper

134

auxiliary facility

200

base plate

201

load bearing surface

202

pulling device

204

rotor

205

rotor shaft

206

inside

208

rib

210

braking surface

212

disc

213

breakthroughs

214

drag surface

215

spokes

216

coupling

218

release device

220

coupling device

222

bars

400

emptying device

402

sloping floor

404

discharge opening

406

pit

408

flushing port

500

transport system

600

Method of maintaining a vertical ball mill

602

step of separation

604

step of lifting

606

arranging step

608

step of weaning

610

relocation step

700

working platform

702

Director

704

stair tower

706

maintenance cabin

800

Frame

802

drive

900

coaming

1000

lifting tab

1200

groove

1300

ferrule

1302

body

1304

hinge

1306

threaded hole

1308

screw spindle

1310

jaws

1312

slot

Claims (15)

1. Vertical ball mill (100), in particular for pre-grinding material to be ground, such as minerals, comprising:

   a rotor (204) that is axially and radially mounted at an upper end and hangs downwards,

   a stator (102) which radially surrounds the rotor (204), is not loaded by a weight of the rotor (204), stands in a self-supporting manner, and has a lateral surface (104) that is oriented tangentially to the rotor (204) and is approximately cylindrical, within a shape tolerance, and

   a base plate (200) that supports a weight of the stator (102),

   wherein the stator (102) is composed of at least two stator segments (112) which may be separated from one another, stand unsupported in the separated state, and may be moved relative to one another,

   wherein each of the stator segments (112) comprises, on at least one side edge of the wall (116), extending from a top edge of a wall (116) forming the lateral surface (104) to a bottom edge of the wall (116), a sealing surface (118) for sealing to the other stator segment (112) in each case, and, on the bottom edge, a standing surface (122) which is dimensioned appropriately for the load and is intended for sealing to the base plate (200),

   wherein the stator segment (112) weighs, in a standing manner, on the base plate (200) with the standing surface (122), in a manner orthogonal within an angular tolerance on a load-bearing surface (201) of the base plate (200).
2. Ball mill (100) according to claim 1,

   in which a plurality of vertically mutually spaced, horizontal, annular segment-shaped ribs (208) are arranged on an inner face (206) of the walls (116), which ribs form inwardly protruding annular brake surfaces (210) on the assembled stator (102), and

   in which the rotor (204) comprises a plurality of vertically mutually spaced, horizontal discs (212), each having an outside annular entraining surface (214), wherein the ribs (208) and the discs (212) are arranged alternately in the vertical direction, and the brake surfaces (210) and the entraining surfaces (214) overlap, at least in part, in the horizontal direction.
3. Ball mill (100) according to either of the preceding claims,
   in which the stator segments (112) each comprise stop elements (124) on an outer face, for lifting and moving the relevant stator segment (112).
4. Ball mill (100) according to claim 3,
   in which the stator segments (112) each comprise stop elements (124) in the region of the bottom edge of the wall (116), which stop elements are configured in particular for fixing hydraulic jacks.
5. Ball mill according to either of claims 3 to 4,
   in which the stop elements (124) define corner points of a virtual horizontal polygon, in particular triangle, the geometrical centre point of which is located on a vertical axis through a centre of gravity of the standing stator segment (112).
6. Ball mill (100) according to any of claims 3 to 5,

   comprising a shifting device (126) for lateral shifting of the mutually separated stator segments (112),

   wherein the shifting device (126) comprises movable auxiliary devices (134) which are designed to be arranged between the stop elements (124) and rails (130) arranged on the ground and extending in parallel, when the stator segment (112) is raised, and to be moved along the rails (130), together with the stator segment (112), when the stator segment (112) is deposited thereon, and

   in which, optionally, the shifting device (126) comprises at least one tilt support (132) for supporting a stop element (124), vertically spaced apart from the standing surface (122), on at least one of the rails (130), in order to prevent tilting of the stator segment (112) during lifting and shifting.
7. Ball mill (100) according to claim 6, in which the rails (130) are recessed into a foundation (110) of the ball mill (100) and, optionally, may be covered by covering devices when not in use.
8. Ball mill (100) according to any of the preceding claims, comprising an emptying device (400) for emptying the ball mill (100), and
   in which, optionally, the emptying device (400) comprises an oblique base (402) within the load-bearing surface (201) of the base plate (200), wherein one of the stator segments (112) comprises an emptying opening (404) of the emptying device (400) in the region of a bottom point of the oblique base (402).
9. Ball mill (100) according to claim 8, in which one of the stator segments (112) comprises a rinsing opening (408) of the emptying device (400) in the region of a top point of the oblique base (402).
10. Ball mill (100) according to any of the preceding claims,

    comprising a frame (108) that is separated from the stator (102),

    wherein supports of the frame (108) are supported on a foundation (110) of the ball mill (100) so as to be laterally spaced apart from the stator (102), and at least one crossbeam of the frame (108) interconnects the supports above the stator (102), wherein a bearing and drive device (106) of the rotor (204) is supported on the crossbeam.
11. Ball mill (100) according to any of the preceding claims,

    comprising a disengagement device (218) for laterally disengaging the rotor (204) that may be decoupled from an upper coupling (216),

    wherein the disengagement device (218) comprises at least one rail (130) and a coupling device (220), wherein the coupling device (220) is designed to be connected to the rotor (204) in the region of the coupling (216), to be lowered onto the rail (130) together with the rotor (204), and to be moved along the rail (130) together with the rotor (204).
12. Ball mill (100) according to claim 10 and claim 11, in which the frame (108) comprises a maintenance cab (706) in the region of the coupling (216).
13. Self-supporting standing stator segment (112) for a vertical ball mill (100) according to any of claims 1 to 12, comprising:

    a wall (116) that is approximately in a shape of a cylinder segment, within a shape tolerance,

    at least one sealing surface (118) that is arranged on a side edge of the wall (116) extending from a top edge of the wall (116) to a bottom edge of the wall (116) and is intended for sealing to another stator segment (112), and

    a standing surface (122) that is arranged on the bottom edge and is dimensioned appropriately for the load, and by means of which the stator segment (112) may be erected on a load-bearing surface (201) of a base plate (200) of the ball mill (100), so as to be orthogonal within an angular tolerance,

    wherein a stator (102) that stands in a self-supporting manner and comprises a lateral surface (104) that is formed by the walls (116) and is approximately cylindrical, within a shape tolerance, may be composed of a plurality of stator segments (112), which stator, in an assembled state, may stand in a loading manner on the base plate (200) for supporting a weight of the stator (102).
14. Method (600) for maintaining a vertical ball mill (100), in particular for pre-grinding material to be ground, such as minerals,

    wherein the vertical ball mill (100) comprises a rotor (204) that is axially and radially mounted at an upper end and hangs downwards, a stator (102) which radially surrounds the rotor (204), is not loaded by a weight of the rotor (204), stands in a self-supporting manner, and has a lateral surface (104) that is oriented tangentially to the rotor (204) and is approximately cylindrical, within a shape tolerance, and a base plate (200) that supports a weight of the stator (102),

    wherein the stator (102) is composed of at least two stator segments (112) which may be separated from one another, stand unsupported in the separated state, and may be moved relative to one another,

    wherein each of the stator segments (112) comprises, on at least one side edge of the wall (116), extending from a top edge of a wall (116) forming the lateral surface (104) to a bottom edge of the wall (116), a sealing surface (118) for sealing to the other stator segment (112) in each case, and, on the bottom edge, a standing surface (122) which is dimensioned appropriately for the load and is intended for sealing to the base plate (200),

    wherein the stator segment (112) weighs, in a standing manner, on the base plate (200) with the standing surface (122), in a manner orthogonal within an angular tolerance on a load-bearing surface (201) of the base plate (200),

    wherein the method (600) comprises:

    separating (602) the stator (102) into the stator segments (112), wherein a stator (102) is separated at the sealing surfaces (118),

    arranging (606) auxiliary devices (134) under at least one of the stator segments (112), and

    lateral shifting (610) of the stator segment (112) and of the auxiliary devices (134) using a shifting device (126).
15. Method (600) according to claim 14, in which the stator segment (112) may be lifted from the base plate (200), using lifting devices, and deposited on the auxiliary devices (134) using the lifting devices.

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