EP2525911B1 - Method of, and apparatus for, the preliminary grinding and finishing of mineral and non-mineral materials - Google Patents

Description

Technical area

The invention relates to a method and a device for pre- and final-grinding of mineral and non-mineral materials, preferably hard and brittle materials such as e.g. Limestone, cement clinker, blastfurnace slag, old concrete or ashes, wherein the material to be crushed is placed in the forming, first roller gap between a driven lower, driven roller and an upper roller, wherein in the region of the apex of the lower, driven roller a quantity of material to processing material is applied as a thickness-adjustable material layer of the lower, driven roller, and the first roller gap is supplied, and wherein the upper roller is elastically adjusted to the lower, driven roller with adjustable contact force and dragged by frictional engagement with the material layer or its own Drive has.

State of the art

The pre-grinding and finish-grinding of preferably hard and brittle materials, e.g. Limestone, cement clinker, blastfurnace slag, old concrete or ashes, traditionally takes place in ball mills and more recently with increasing trend in vertical roller mills as well as in high-pressure roller mills.

From the DE 27 08 053 B2 is known as a high-pressure roller mill known as a high-pressure roller mill, in which the crushing of the material by a single compressive stress between two surfaces at pressures well above 50 MPa in the gap of two counter-rotating cylindrical rollers.

The disadvantage is that the high-pressure roller mill works with very high pressures, which are only conditionally adjustable and lead to a complex and very heavy machine design. In addition, the high-pressure roller mill has an unfavorable Throughput speed behavior. The throughput characteristic of the high-pressure roller mill is non-linear, ie, depending on the material properties and on the geometry of the stress surfaces, the throughput decreases sharply with increasing peripheral speed with a simultaneous increase in the specific energy requirement. Large throughputs are therefore only possible by broadening the grinding rollers with a proportional increase in pressing forces, but this is limited by machine technology.

To improve the operation as well as the energy utilization of vertical roller mills and high-pressure roller mills, it is out WO 99/54044 Known to inject the material to be crushed as a defined layer on a rotating plate belt in the gap formed between a hydro-pneumatically employed on the material layer roll and a moving plate belt horizontally and using specific compressive forces in the range of 6 to 30 MPa or 6000 up to 30000 kN / m ² to claim. Extensive research has shown that due to technical limitations, this principle can not replace either the vertical roller mill or the high-pressure roller mill.

First, the material injection of a prepared on a rotating slat strip material layer requires great technical effort, since the slat strip must be designed for the high compressive stresses in the stress zone, thereby controlling the wear of both the traction device and the plating as well as to limit noise pollution significant speed and throughput reductions must be accepted.

Second, material injection using a plate belt drawn over the driven lower roller results in high machine-related losses.

Thirdly, the arrangement of a grinding roller mounted hydro-pneumatically on the horizontally guided plate belt impairs the material feed, causing material jams and material overflows can come.

Fourth, an efficient pulverization up to a Blaine value of 5000 and higher, due to the high proportion of circulating material and its high proportion of air connection, taking into account the Mahlrollengeschwindigkeiten of up to 4 m / s and higher with the help of a single pressure roller is not fully feasible. The Blaine value is a standardized measure of the degree of fine grinding of cement and results from its specific surface area (cm ² / g). Standard portland cement CEM I 32.5 has a Blaine value of 3,000 to 3,500.

From the DE 38 23 929 A1 is a roller press with a drive roller and two smaller staggered idler rollers known. The material to be ground falls from the discharge-side end of a conveyor belt into the nip formed by the drive roller and the first idler roller. Alternatively, the material to be ground can also be conveyed into the nip by means of a downpipe. The compressed material to be ground is then mixed with recycled material and then the second nip, which is formed from the drive roller and the second idler roller, fed, whereby the product is ground to the desired product fineness. The grinding pressures are adjustable to values of between 50 and 600 MPa.

From the DE 28 30 864 A1 is a roller mill with a hard roller, a vertically offset play roller and a material application device known, wherein the defined by the centers of the two rolls line with the horizontal forms an angle of between 35 and 75 degrees. The discharge-side end of the crop-feeding device is located above the uppermost peripheral region of the lower-mounted fixed roller. A slider is used to adjust the height of the material layer, which is fed to the nip. The material application device can have at least one movable element which gives the material to be ground a component of movement in the direction of the roll movement, so that the material to be ground reaches the circumferential speed of the roller more quickly.

From the WO 00/56458 A1 is a multi-roll mill for grinding granular material having a driven roller and three non-driven rollers. Each of the grinding rollers is equipped with a hydraulic mechanism for applying individual grinding pressures. In addition, the mill has a supply that allows to adjust the layer height of the raw material, which is placed in the first nip. The non-driven rollers may be mechanically, hydraulically or electrically braked, wherein by means of the braking device, a shear stress in the grinding area can be generated.

From the DE 195 14 955 C2 For example, a multi-roll mill is known for grinding food and feed or other bulk goods having two fixed rollers and two grinding rollers associated with each fixed roller. The material to be ground is fed into the first grinding gap formed between the hard roll and the upper grinding roll and then fed to the second grinding gap formed between the hard roll and the lower grinding roll. The fixed rollers and the grinding rollers have a common drive mechanism 18th

From the EP 0 399 192 A1 For example, a roller press for grinding granular material is known which comprises two rollers, a crop hopper and a precompressor roller for compacting the feed prior to feeding to the nip. The rollers have their own drive and their own pressure generating mechanisms.

From the WO 2009/037356 A1 is a roller mill for pre and final grinding of mineral and non-mineral materials such. Example, limestone, cement clinker, granulated blastfurnace, or old concrete ashes, known in which the millbase from a crusher associated with the material feed container with a arranged at the outlet and in its speed continuously variable roller or Zellenradaufgeber as defined and laterally limited material layer with a predetermined thickness on the Top of the sideways driven driven lower roller fed, accelerated to roller speed and continuously transported in the formed gap with the offset above the driven roller arranged upper roller, hydropneumatically under application of specific compressive forces of 2 to 7.5 kN / mm claimed and then disagglomerated by a preferably fast-running impact rotor within the crusher. This results in a high energy utilization and a lower mechanical construction, maintenance and repair costs. It is possible to use it in a wide range for the comminution of different materials, and a linear throughput and speed behavior can be realized both in part-load operation and in high mass throughputs.

The object of the invention is to provide a method and associated apparatus for pre- and final grinding of mineral and non-mineral materials, such as e.g. Limestone, cement clinker, granulated blastfurnace, old concrete or ashes, with finenesses of a Blaine value of up to 5000 and higher, which is characterized by a high energy efficiency and low mechanical construction, maintenance and upkeep in one wide range for crushing different materials can be used and realized a linear throughput-speed behavior both in partial load operation and under conditions of high mass flow rates.

This object is achieved by a method according to claim 1 and an apparatus according to claim 6. The material to be shredded from a material feed container is given by means of a conveyor belt as laterally limited material web the first roller nip. Advantageous embodiments of the invention are specified in the subclaims.

The usually consisting of fresh and Umlaufgut regrind is from a crusher belonging to the material feed container as a defined and laterally limited material layer with a predetermined thickness via a conveyor belt with variable speed, the speed is preferably adapted to the peripheral speed of the driven lower roller in the Abandoned area of the vertex of the driven, lower roller. Knocker rollers, which are arranged in the region of the conveyor belt, thereby already provide for a first venting of the ground material. The material to be ground is continuously supplied from the driven lower roll to the first nip formed with the upper pressure roll disposed above the lower driven roll and subjected to hydropneumatic application of specific compressive forces of 1,000 to 3,500 kN / m ² . Due to the stress caused by the upper grinding roller, the material to be ground is repeatedly deaerated on the one hand and already pre-shredded on the other hand. The final comminution then takes place in the second grinding gap, which is formed with the lateral pressure roller and which is also claimed hydropneumatically using specific compressive forces of 1,000 to 5,000 kN / m ² . Subsequently, the ground material is deagglomerated by a preferably fast-running impact rotor within the crushing device. On the disagglomerator can be dispensed with if the new crushing z. B. is connected as Vormühle composite with a ball mill.

The device consists of three rollers, namely a lower, driven roller, an upper roller and a laterally staggered roller. The upper roller is arranged at 70 ° to 90 °, preferably 80 ° to 90 °, relative to the horizontal opposite to the direction of rotation of the lower roller and is at a pressure of up to 3,500 kN / m ² (corresponds to a value of up to approx. 3 to 5.5 kN / mm (force / gap length)) on the material-occupied load surface of the driven lower roller employed. The lateral roller is arranged at 45 ° to 60 °, preferably about 45 °, relative to the horizontal opposite to the direction of rotation of the lower roller and is at a pressure of up to about 5,000 kN / m ² (corresponds to a value of up to 7.5 kN / mm (force / gap length)) on the material occupied load surface of the driven lower roller employed. The upper and laterally offset rollers are connected to a hydro-pneumatic lever system for generating the grinding force. They can either be equipped with their own drive or be carried along by the lower roller. The claimed material, which emerges more or less agglomerated from the second roller gap, is finally fed to a directly downstream deagglomerator.

The material supply container is a vertical shaft which is above the beginning of a circulating conveyor belt. The top of the conveyor belt is bounded by two lateral, parallel plates. The side parts of the material feed container overlap slightly with the inside of these plates so that the material to be ground is fed into the area bounded by the plates. The outlet opening of the material feed container can be regulated by means of a height-adjustable lock. The material layer fed to the first nip is thereby bounded laterally and has a substantially rectangular cross section, i. a uniform strength. At the bottom of the plates elastic lips are provided, which rest against the conveyor belt.

Under the upper run of the conveyor belt several knocker rollers are arranged. By means of the knocker rollers, the material lying on the conveyor belt is vibrated, whereby the homogeneity and uniformity of the grinding material layer is improved and the material to be ground is deaerated.

In the first roller nip formed between the upper and lower rollers, the material to be ground is pressed onto the lower roller so that it adheres to the lower roller and inserted for further processing defined good bed is achieved. The required compressive force depends on the moisture and graininess of the material to be ground.

The pressure of the first roller gap is adjusted so that no vibrations occur in the lateral roller. Vibrations occur when the pressure in the first roll nip is too high.

Because the homogeneity and uniformity of the good bed is maintained even when fed into the second roller gap, the pressure in the second roller gap in the range of 0 to 10 kN / mm can be set arbitrarily and according to the desired size reduction.

Preferably, while maintaining a maximum possible material layer thickness of the material throughput is controlled by the roller gap via a stepless change in the peripheral speed of the driven roller.

In the case of the final grinding, the proportion of material with oversize size is preferably returned to the comminution process, the mass flow of the circulating product being kept constant by regulation of the fresh material fed to the grinding process.

Preferably, depending on the material properties and the desired comminution result, the grinding force transmitted with the upper and the lateral roll is controlled during the grinding process and can be set independently of one another.

Preferably, by means of the material feeding device, a mass flow proportional to the peripheral speed of the rollers is supplied with an approximately constant layer thickness in the apex region of the lower roller.

Preferably, the crushing device is supplied to the circulating material with added fresh material.

Preferably, the thickness of the material layer is continuously measured and visualized before its use in the roller gap during operation.

Preferably, the diameter ratio of the driven lower roll to the upper and side rolls is ≥ 1.5 and more preferably 2.0 to 3.0 (In Fig. 3 this diameter ratio is not met.)

Preferably, to generate the grinding force, the upper and side rollers are connected via lever systems with at least one hydraulic cylinder.

Preferably, on both sides of the end faces of the lower roller for lateral delimitation of the material layer exchangeable shelves are arranged. The shelves can be segmented.

Preferably, the stress surfaces of the rollers are wear-resistant and structured by build-up welding or mechanical machining.

The knocker rollers are n-square rollers, e.g. in cross-section triangular rollers which are mounted below the conveyor belt and are in mechanical contact with the conveyor belt of the material feeding device. The rotation of the n-shaped knocker rollers results in an n-fold knocking process per revolution, through which the conveyor belt is exposed to permanent vibrations. Due to the vibrations of the conveyor belt, the material layer located on the conveyor belt is compressed or vented.

The drive of the upper and the lateral roller serves to accelerate the start-up of the roller mill, especially in large and heavy equipment. It is thereby also possible to selectively run the pressure rollers during the grinding process slower than the hard roller, whereby the material to be ground in addition to the vertical roller pressure still undergoes a horizontal shear pressure component.

The solution according to the invention, which realizes these features, has numerous other advantages over the known high-pressure roller mill, belt roller mill and multi-roller mill. The advantages of the multi-roller mill according to the invention consist in procedural terms that both specific depending on the material and on the grinding task to be solved specific grinding forces can be set arbitrarily in two grinding stages and with the parameters of the specific grinding force and the material layer thickness the crushing result regardless of the roller speed can be set and kept constant. In the first grinding stage For example, forces of up to 3,500 kN / m ^{2 can be set,} and in the second grinding stage, grinding forces of up to 5,000 kN / m ² can be set. It has proved particularly in the Feinstmahlung up to Blaine values of 5,000 and higher of hard and brittle materials such as cement clinker and slag sandals advantageous to perform the stress using high specific grinding forces whenever a particularly high quality fines with high Air entrainment in the circuit with a sifter should be produced economically at the lowest possible circulating numbers.

From a technical point of view, the advantages of the shredding device according to the invention over that of the WO 2009/037356 A1 Known crushing device is that the additional grinding roller a better Feinstmahlung is made possible by the finished product quality can be achieved with Blaine values of up to 5,000 and higher.

Brief description of the drawings

• Fig. 1 die erfindungsgemäße Vorrichtung in schematischer Darstellung,
• Fig. 2 die Fördereinrichtung im Schnitt und
• Fig. 3 Details der Zuführung des Mahlguts von dem Förderband in den ersten Walzenspalt.

The invention will be explained in more detail with reference to exemplary embodiments. The accompanying drawings show:

• Fig. 1 the device according to the invention in a schematic representation,
• Fig. 2 the conveyor in section and
• Fig. 3 Details of the feeding of the ground material from the conveyor belt in the first nip.

Way (s) for carrying out the invention

FIG. 1 shows a schematic representation of the inventive crushing device consisting of a driven, lower roller 10, an upper roller 12, a laterally arranged rollers 14, and from a material feeding and discharging 18. The material feeding and discharging device 18 has a material bunker 20, a conveyor belt 22, a device 24 for adjusting the layer height of the ground material, and six knocker rollers 26.

The lower roller 10 is corresponding to the in FIG. 1 driven arrow shown. Above the driven, lower roller 10, the upper roller 12 is arranged. The lateral roller 14 is offset laterally attached at an angle of about 45 ° relative to the horizontal opposite to the direction of rotation of the lower roller 10. The upper and the lateral rollers 12, 14 are made hydropneumatically via a lever system 30 by means of a hydraulic cylinder against the lower roller 10. The upper and side rollers 12 and 14 are dragged frictionally through the material-loaded surface of the driven, lower roller 10 or may have its own drive. The diameter of the driven, lower roller 10 is twice as large as the diameter of the upper and the lateral roller 12, 14. In the region of the apex of the driven, lower roller 10, the material feeding and discharging device 18 is arranged. The ground material, which is in a level controlled container 20, passes as a defined layer of material 32 with a predetermined thickness on the conveyor belt 22. A first deaeration phase of the ground material is achieved by the stress with the conveyor belt arranged on the knocker rollers 26. The material to be ground is fed continuously and at a defined speed to the lower roller 10 and then to the first load or roller gap 34 formed by the rollers 10 and 12. In the first roller nip 34, the material to be ground is simultaneously deaerated and pre-shredded. The final crushing then takes place in the second roller nip 36, which is formed by the laterally arranged roller 14 and the driven, lower roller 10.

How to get in FIG. 2 detects, ends the lower end of the material feed container 20 between two plates 38, which define on the upper side of the conveyor belt 22, the area in which the material to be ground is transported. For flexible sealing of this area elastic lips 40 are provided at the lower end of the plates 38, which bear against the top of the conveyor belt 22.

The conveyor belt 22 is slightly inclined in the transport direction ( FIG. 3 ). At the front end of the conveyor belt 22, a plate 42 is attached, which bridges the distance between the conveyor belt 22 and lower roller 10, so that the homogeneity of the ground material is maintained, and the ground material can be introduced with a thickness in the first nip, transversely to the Transport direction is extremely uniform. The lateral plates 38 are continued to the front end of the plate 42. The surface of the driven, lower roller 10 is also bounded laterally by annular plates 44, wherein the upper roller 12 and also in FIG. 3 non-drawn lateral roller 14 extend within these annular plates 44. The material web is thereby laterally limited within the first and second roller gap 34, 36.

After the lateral roller 14, a scraper roller 46 is still provided, which cleans the surface of the lower roller 10 of adhering material. The scraper roller 46 rotates counter to the lower roller 10.

10

angetriebene untere Rolle

12

obere Rolle

14

seitliche Rolle

18

Materialaufgabeeinrichtung

20

Materialaufgabebehälter

22

Förderband

24

Einrichtung zur Einstellung der Schichtdicke des Mahlguts

26

Klopferrolle

30

Hebelsystem

32

Materialschicht

34

erster Rollenspalt

36

zweiter Rollenspalt

38

Platten

40

Dichtung

42

Blech

44

kreisringförmige Platten

46

Kratzerrolle

LIST OF REFERENCE NUMBERS

10

powered lower roller

12

upper roll

14

lateral role

18

Material feeder

20

Material feed container

22

conveyor belt

24

Device for adjusting the layer thickness of the ground material

26

Veteran role

30

lever system

32

material layer

34

first roll gap

36

second roll gap

38

plates

40

poetry

42

sheet

44

annular plates

46

scratches role

Claims (10)

1. Method for coarse grinding and fine grinding of mineral and non-mineral materials, preferably hard and brittle materials such as e.g. limestone, cement clinker, slag sand, old concrete or ashes,
   wherein the material to be comminuted is fed from a material feed container (20) via a conveyor belt (22) into the first roller gap (34) which forms between a lower driven roller (10) and an upper roller (12),
   wherein in the region of the vertex of the lower driven roller (10) a quantity of the material to be processed is fed as a material layer (32), the thickness of which can be adjusted, to the lower driven roller (10) and supplied to the first roller gap (34),
   wherein the upper roller (12) is elastically set against the lower driven roller (10) with an adjustable pressing force and dragged by friction fit with the material layer (32) or has a dedicated drive,
   wherein the speed of the conveyor belt (22) is adapted to the circumferential speed of the lower driven roller (10),
   wherein the ground material, after passing through the first roller gap (34), is supplied to a second roller gap (36) which is formed by the lower driven roller (10) and a roller arranged laterally offset (14), and
   wherein the roller arranged laterally offset (14) is likewise elastically set against the lower driven roller (10) with an adjustable pressing force and dragged by friction fit with the material layer (32) or has a dedicated drive,
   characterized in that
   the conveyor belt (22) is exposed to vibrations, by means of which the material layer (32) located on the conveyor belt (22) is vented,
   the material to be comminuted is fed via the conveyor belt (22) as a defined and laterally limited material layer with a predefined thickness into the first roller gap (34),
   the upper roller (12) is arranged at 70° to 90° relative to the horizontal counter to the rotational direction of the lower roller (10), and
   the roller arranged laterally offset (14) is arranged at 45° to 60° relative to the horizontal counter to the rotational direction of the lower roller (10).
2. Method according to claim 1, wherein the material to be comminuted is fed from a material feed container (20) by means of a conveyor belt (22) as a laterally limited material web to the first roller gap (34).
3. Method according to one of claims 1 to 2, wherein the upper roller and the lateral roller (12, 14) are additionally accelerated by their dedicated drive when the grinding device starts up or are moved during the grinding process at a different speed to the lower roller (10), with the result that an additional shearing force is exerted on the ground material due to the relative movement of the rollers (10, 12, 14).
4. Method according to one of the preceding claims, wherein the proportion of material with an excessive grain size is supplied to the comminution process again during a fine grinding, wherein the mass flow of the circulating material is kept constant by regulating the fresh material supplied to the grinding process.
5. Method according to one of the preceding claims, wherein the grinding forces transferred with the upper roller and the lateral roller (12, 14) are adjusted in a regulated manner as a function of the material properties and the desired comminution result during the grinding process.
6. Device for coarse grinding and fine grinding of mineral and non-mineral materials, preferably hard and brittle materials such as e.g. limestone, cement clinker, slag sand, old concrete or ashes,
   with a comminution device which has a lower driven roller (10) and an upper roller (12) which are mounted horizontally and arranged one above the other and form a first roller gap (34), wherein the lower driven roller (10) is driven at a grinding track speed,
   with a feed apparatus (18), with a material feed container (20) and a conveyor belt (22) which feeds the ground material onto the lower driven roller (10), wherein the speed of the conveyor belt (22) is adapted to the circumferential speed of the lower driven roller (10), and
   with a further roller arranged laterally offset (14) in addition to the upper roller (12), wherein the further roller arranged laterally offset (14) forms a second roller gap (36) with the lower driven roller (10) and which is likewise elastically set against the lower driven roller (10) with an adjustable pressing force and dragged by friction fit with the material layer (32) or has a dedicated drive,
   characterized in that
   beater rollers (26) are arranged below the conveyor belt (22), by means of which the material to be comminuted on the conveyor belt (22) is vented by vibrations,
   the upper roller (12) is arranged at 70° to 90° relative to the horizontal counter to the rotational direction of the lower roller (10), and
   the roller arranged laterally offset (14) is arranged at 45° to 60° relative to the horizontal counter to the rotational direction of the lower roller (10).
7. Device according to claim 6, with a conveyor belt (22), which feeds the material to be comminuted from a material feed container (20) as a laterally limited material web to the first roller gap (34).
8. Device according to one of claims 6 or 7, wherein the upper roller and the roller arranged laterally offset (12, 14) each have a dedicated drive.
9. Device according to one of claims 6 to 8, wherein the rollers (12, 14) are connected via a lever system (30) to at least one hydraulic cylinder in order to generate the grinding force.
10. Device according to claim 6, wherein a material feed and discharge apparatus arranged in the vertex region laterally offset relative to the lower driven roller (10) has a filling-level-controlled material feed container (20), a conveyor belt (22) arranged at the material outlet, an apparatus (24) for adjusting the layer thickness of the material layer (32) and a number of beater rollers (26) for venting the material layer (32).

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