Two-stage grinding of material for the production of a binder, in particular a cement.

Abstract

The present invention relates to a device 10 for grinding a mineral material, wherein the device comprises a first grinding device 20 and a second grinding device 30 downstream of the first grinding device 20, wherein the first grinding device 20 is used to achieve a fineness of 2500 to 5000 cm⁻¹ 2 / g is designed according to Blaine, wherein the second grinding device 30 has an energy input of at least 100 kW / m 3 exhibits.

Description

[0001] The invention relates to a process for two-stage grinding and for producing a binder, in particular a cement, wherein the second stage of grinding with high energy input makes it possible to increase the reactivity.

[0002] DE 10 2017 114 831 A1 discloses a process for processing fly ash as well as a plant and a process for producing cement.

[0003] From DE 10 2017 115 994 A1 a two-stage grinding circuit and a method for producing a ground product by means of a two-stage grinding are known.

[0004] DE 10 2017 117 985 A1 discloses a process and a plant for producing cement.

[0005] A process for processing fly ash is known from DE 10 2019 008 945 B4.

[0006] DE 19 501 616 A1 discloses a grinding process and a plant for comminuting ground material.

[0007] Methods for mechanical activation are also known.

[0008] WO 2017 / 008 863 A1 discloses a method and a plant arrangement for processing and activating a raw material.

[0009] EP 3 909 682 A1 discloses a method and a roller mill for thermomechanically activating a clay mixture.

[0010] DE 10 2015 106 109 A1 discloses a process for the tribochemical activation of binders and additives.

[0011] DE 10 2017 114 831 A1 discloses a process for processing fly ash and a process for producing cement.

[0012] The mechanical activation of clays is known from the subsequently published DE 10 2023 106 210.

[0013] The mechanical activation of clays is known from the subsequently published DE 10 2023 106 217.

[0014] The combined mechanical and thermal activation of clays is known from the subsequently published DE 10 2023 106 221.

[0015] The subsequently published DE 10 2023 106 222 describes the color optimization during the mechanical activation of clays.

[0016] The object of the invention is to provide a grinding process for a binder which enables optimized product quality.

[0017] This object is achieved by the device having the features specified in claim 1 and by the method having the features specified in claim 11. Advantageous further developments emerge from the subclaims, the following description, and the drawing.

[0018] The device according to the invention is used for grinding a mineral material, in particular for the production of cement. Examples of these mineral materials are clinker, gypsum, activated clays, sand, old cement brick, slag, and the like. The device comprises a first grinding device and a second grinding device downstream of the first grinding device. The mineral material to be ground thus first passes through the first grinding device and then the second grinding device. The first grinding device is designed to achieve a fineness of 2500 to 5000 cm 2 / g according to Blaine. This corresponds to a fineness that is approximately equal to the fineness of the individual components in conventional cements. The second grinding device has an energy input of at least 100 kW / m 3This corresponds to a comparatively high energy input of a micromill and exceeds the usual amount of energy input. The goal is to achieve a particularly advantageous property of the binder, which in turn makes it possible to increase the proportion of substitutes and thus conserve valuable primary raw materials.

[0019] In a further embodiment of the invention, the second grinding device is an agitated ball mill. The agitated ball mill is particularly preferably operated in a continuous flow, i.e., continuous mode. This makes high energy inputs technically easy to implement, and also allows for simple throughput and series connection with a continuous first grinding device.

[0020] In a further embodiment of the invention, the second grinding device has an energy input of at least 250 kW / m 3This further enhances the effect, which in particular allows for an increase in the proportion of substitutes.

[0021] In a further embodiment of the invention, the first grinding device is a vertical roller mill or a high-pressure roller mill. These types have proven effective in grinding precursors into finished cement.

[0022] In a further embodiment of the invention, the first grinding device has a grinding circuit with a size separation device. This means that the coarse material to be ground is ground in the first grinding device and then transferred to the size separation device. There, the material to be ground is separated into a coarse fraction and a fine fraction, the coarse fraction is fed to the first grinding device for further comminution, and the fine fraction is then fed to the second grinding device. This makes it easier to achieve a higher degree of fineness in the first grinding device. The size separation device is preferably a classifier. In this case, the classifier can also be integrated directly into a housing with the first grinding device.

[0023] In a further embodiment of the invention, the device comprises two second grinding devices connected in parallel. This allows, on the one hand, to increase the throughput. Alternatively, the two parallel second grinding devices can be used specifically to produce two different product qualities. For example, and preferably, the two parallel second grinding devices are stirred ball mills, and the two parallel second grinding devices are filled with different balls.

[0024] In a further embodiment of the invention, the ratio of the grinding energy input between the first grinding device and the second grinding device is at most 2:1. For example, the first grinding device can input a grinding energy of 2 MW, the second grinding device 1 MW, which corresponds to a ratio of 2:1. Likewise, with the same total energy, the first grinding device could input 1.5 MW and the second grinding device 1.5 MW, which then corresponds to a ratio of 1:1. Since the first stage in the first grinding device already produces comminution to an approximately suitable fineness, the energy input in the second grinding device is largely used for product optimization, which in turn makes it possible to increase the substitute content.

[0025] In a further embodiment of the invention, a reactant feed is arranged between the first grinding device and the second grinding device. Thus, additional material can be added to the mineral material comminuted in the first grinding device, particularly if it already has the required fineness. This can, for example, be one of the precursors selected from the group comprising fly ash, calcined clay, clay, granulated blast furnace slag, limestone, natural and naturally tempered pozzolanic slate, and silicate dust. If the first grinding device has a size separation device, the additional material can also, for example and preferably, be applied to the size separation device.

[0026] In a further aspect, the invention relates to a method for producing a binder from at least one first precursor by grinding. Typically, the individual components of a cement are mixed prior to grinding and ground together, thereby intimately mixing them. The material is first ground in a first grinding device to a first ground material with a fineness of 2500 to 5000 cm 2 / g according to Blaine. The first grinding material is fed into a second grinding device. The material is milled in the second grinding device with an energy input of at least 100 kW / m 3 ground into a second material. The very intensive grinding in the second step of an already comparatively fine material has a positive effect, improving its binding properties. This makes it possible, for example, to increase the substitute content in cement and thus conserve valuable primary raw materials.

[0027] In a further embodiment of the invention, a second precursor is added to the first millbase. The second precursor is preferably selected from the group comprising fly ash, calcined clay, clay, granulated blast furnace slag, limestone, natural and naturally tempered pozzolana slate, and silicate dust.

[0028] In a further embodiment of the invention, the second grinding material is ground to a fineness of 5000 to 15000 cm 2 / g according to Blaine. The second grinding material is preferably ground to a fineness of 7000 to 15000 cm 2 / g according to Blaine. It is particularly preferred that the second grinding material be ground to a fineness of 7500 to 15000 cm 2 / g ground according to Blaine.

[0029] In a further embodiment of the invention, the precursor product or products is or are selected from the group comprising clinker, gypsum, activated clays, slag, for example granulated blast furnace slag, sand, old cement brick.

[0030] In a further embodiment of the invention, the material is milled in the second milling device with an energy input of at least 250 kW / m 3 ground into a second grind.

[0031] The device according to the invention is explained in more detail below using an embodiment shown in the drawing. Fig. 1 exemplary embodiment

[0032] In Fig. 1 shows an exemplary embodiment of a device 10 according to the invention. A first precursor 51, for example clinker, is fed to a first grinding device 20, for example a vertical roller mill, and ground to a fineness of 4000 cm 2 / g. The ground material is fed to a size separation device 40. The coarse fraction is fed again to the first grinding device 20. The fine fraction is provided with a second precursor 52, for example activated clay, and fed to a second grinding device 30. There, the material is milled with an energy input of 300 kW / m 3 to a fineness of 10000 cm 2 / g to obtain the finished product, a binding agent. Reference sign 10 Device 20 first grinding device 30 second grinding device 40 size separator 51 first intermediate product 52 second precursor QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 114 831 A1 [0002, 0011] DE 10 2017 115 994 A1

[0003] DE 10 2017 117 985 A1

[0004] DE 10 2019 008 945 B4

[0005] DE 19 501 616 A1

[0006] WO 2017 / 008 863 A1

[0008] EP 3 909 682 A1

[0009] DE 10 2015 106 109 A1

[0010] DE 10 2023 106 210

[0012] DE 10 2023 106 217

[0013] DE 10 2023 106 221

[0014] DE 10 2023 106 222

[0015]

Claims

[1] Device (10) for grinding a mineral material, wherein the device comprises a first grinding device (20) and a second grinding device (30) connected downstream of the first grinding device (20), wherein the first grinding device (20) is designed to achieve a fineness of 2500 to 5000 cm 2 / g according to Blaine, wherein the second grinding device (30) has an energy input of at least 100 kW / m 3 has. [2] Device (10) according to claim 1, characterized by that the second grinding device (30) is a stirred ball mill. [3] Device (10) according to one of the preceding claims, characterized by that the second grinding device (30) has an energy input of at least 250 kW / m 3 has. [4] Device (10) according to one of the preceding claims, characterized by that the first grinding device (20) is a vertical roller mill or a material bed roller mill. [5] Device according to one of the preceding claims, characterized by that the first grinding device (20) has a grinding circuit with a size separation device (40). [6] Device (10) according to claim 5, characterized by that the size separating device (40) is a sifter. [7] Device (10) according to one of the preceding claims, characterized by that the device (10) has two second grinding devices (30) connected in parallel. [8] Device (10) according to claim 7, characterized by that the two parallel-connected second grinding devices (30) are agitator ball mills, wherein the two parallel-connected second grinding devices (30) are filled with different balls. [9] Device (10) according to one of the preceding claims, characterized by that the ratio of the introduced grinding energy between the first grinding device (20) and the second grinding device (30) is at most 2:

1. [10] Device (10) according to one of the preceding claims, characterized by that an educt feed is arranged between the first grinding device (20) and the second grinding device (30). [11] Method for producing a binder from at least one first precursor (51) by grinding, wherein the material is first ground in a first grinding device (20) to a first ground material with a fineness of 2500 to 5000 cm 2 / g according to Blaine, wherein the first grinding material is introduced into a second grinding device (30), wherein the material in the second grinding device (30) is milled with an energy input of at least 100 kW / m 3 is ground into a second grind. [12] Method according to claim 11, characterized by that a second pre-product (51) is added to the first ground material. [13] Method according to one of claims 11 to 12, characterized by that the second grinding material is fined to a fineness of 5000 to 15000 cm2 / g is ground according to Blaine. [14] Method according to claim 13, characterized by that the second grinding material has a fineness of 7000 to 15000 cm 2 / g is ground according to Blaine. [15] Method according to one of claims 11 to 14, characterized by that the precursor product (51, 52) or the precursors (51, 52) are selected from the group comprising clinker, gypsum, activated clays, slag, for example granulated blast furnace slag, sand, old cement brick. [16] Method according to one of claims 11 to 15, characterized by that the material in the second grinding device (30) with an energy input of at least 250 kW / m 3 is ground into a second grind.

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