CALIMINATION SYSTEM AND PROCESS FOR LOW-CARBON CEMENT CLINKER

Abstract

SYSTEM AND METHOD FOR CALCINATING LOW-CARBON CEMENT CLINKER The present invention relates to a device and method for calcining low-carbon cement clinker. The calcination device comprises: a kaolin calcination unit including a preheater and a decomposition kiln; the preheater is equipped with a feed port and a discharge port; the decomposition kiln is equipped with a fuel addition port and a raw material inlet; and a cement calcination unit configured for calcining and generating cement clinker. Figure for abstract: Figure 1

Description

Title of the invention: SYSTEM AND METHOD FOR CALIMINATING LOW-CARBON CEMENT CLINKER technical field

[0001] The present invention relates to the technical field of cement manufacturing, and in particular a calcination system and process for low carbon cement clinker. PREVIOUS ART

[0002] The main carbon dioxide emissions in cementitious material production processes are generated by the decomposition of carbonate minerals during clinker calcination, which accounts for 60% or more of the carbon dioxide emissions of an entire production process. Therefore, the main measures currently being adopted by the cement industry consist of developing alternative raw materials and technologies for saving energy and reducing consumption in production processes, as well as reducing the quantities of clinker used in cement and overall energy consumption. Summary of the invention

[0003] In this regard, the present invention provides a calcination system and method for low carbon cement clinker, in order to solve the problems of using large quantities of clinker in cement and high energy consumption.

[0004] In a first aspect, the invention provides a calcination system for low-carbon cement clinker. The calcination system comprises:

[0005] a kaolin calcination unit comprising a preheater and a decomposition furnace, in which

[0006] The preheater is equipped with a multi-stage cyclone cylinder; the preheater is equipped with a supply port and a discharge port;

[0007] The decomposition furnace is equipped with a fuel supply port and a raw material inlet; the raw material inlet is connected to the discharge port; activated kaolin is generated by the decomposition furnace via calcination; and

[0008] the decomposition furnace has a calcination temperature of 700°C to 850°C and a calcination time of 0 h to 1.5 h, and the calcination atmosphere in the decomposition furnace is an oxygen-enriched atmosphere or a CO-reducing atmosphere; and

[0009] a cement calcination assembly configured to generate cement clinker via calcination, wherein activated kaolin is added to the discharge side of the cement calcination process according to a predetermined ratio of activated kaolin to cement clinker.

[0010] The beneficial effects are as follows: in examples of the invention, kaolin is added based on a ratio of raw cement material, so that the amount of carbon-containing raw materials used in clinker production and the carbon emissions from the clinker can be reduced, and the hydration rate of the cement clinker adjusted. Furthermore, the kaolin can be calcined and activated, and at the same time, the calcined kaolin can be added to the discharge of the entire cement calcination system. For example, by collaboratively cooling the discharge port at the head of a rotary kiln or at the material inlet of a grate cooler, it is possible to save on the total energy consumed and reduce the carbon in the calcination system. In addition, the layered aluminosilicate structure in the kaolin is dehydrated and decomposed at high temperature, and a structural reorganization is achieved.Six-coordinated aluminum ions are transformed into four-coordinated activated alumina, which exhibits higher chemical reaction activity. Some silicon-oxygen bonds in the layered structure are broken, resulting in the formation of island-like active silicon oxide, further enhancing material activity. Furthermore, by increasing specific surface areas and changing the average diameter and hole size, the surface area of ​​the material expands, and its internal structure becomes more porous, thus improving contact areas with other substances and reaction efficiency. Consequently, the active sites on the surface and structure of the cement clinker can be increased, and the performance of the final cement product can be significantly improved.For example, cohesive strength can be increased, durability improved, or other physical or chemical properties can be adjusted.

[0011] In an optional embodiment, the preheater is equipped with a three-stage cyclone cylinder comprising a first cyclone cylinder, a second cyclone cylinder and a third cyclone cylinder.

[0012] The first cyclone cylinder is provided with a first air inlet cylinder and two first cyclones arranged parallel to a tail termination of the first air inlet cylinder. The first air inlet cylinder is provided with a first air inlet and the supply port. The top of the first cyclone is provided with a first exhaust port. The base of the first cyclone is provided with a first discharge port.

[0013] The second cyclone cylinder is equipped with a second air inlet cylinder and a second cyclone connected to a tail termination of the second air inlet cylinder. The second air inlet cylinder is equipped with a second inlet of air and a pair of return ports. The top of the second cyclone has a second exhaust port. The base of the second cyclone has a second discharge port.

[0014] The pair of return ports is connected to the first two discharge ports respectively. The second exhaust port is connected to the first air inlet. The second discharge port constitutes the discharge port of the preheater.

[0015] The third cyclone cylinder is equipped with a third air inlet cylinder and a third cyclone. One end of the third air inlet cylinder communicates with a flue gas outlet from the decomposition furnace. The other end of the third air inlet cylinder is connected to the third cyclone. The top of the third cyclone is equipped with a third exhaust port. The base of the third cyclone is equipped with a third discharge port.

[0016] The third exhaust port is connected to the second air inlet. The waste is discharged through the third discharge port.

[0017] In a first embodiment, the decomposition furnace has a calcination temperature of 750°C and a calcination time of 1 h, and the calcination atmosphere in the decomposition furnace is an oxygen-enriched atmosphere.

[0018] In the first embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 10% of activated kaolin to the final product.

[0019] In a second embodiment, an area of ​​the second exhaust port of the second cyclone is 1.4 m2 to 1.6 m2, and a height of an external cylinder of the second cyclone is 1.9 m to 2.1 m; and the decomposition furnace is provided with two fuel addition ports and a single raw material inlet, and the fuel addition ports are located on one side of the raw material inlet.

[0020] In the second embodiment, the calcination temperature is 700°C to 850°C, the calcination time is 1 h, and the calcination atmosphere in the decomposition furnace is a CO atmosphere.

[0021] In the second embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 15% of activated kaolin to the final product.

[0022] In a third embodiment, a CO-reducing tube is additionally arranged between the second air inlet and the third exhaust port of the third cyclone. The decomposition furnace is provided with three fuel addition ports and three raw material inlets. The fuel addition ports are oriented facing the opposite side of the raw material inlets. The addition ports Fuel tanks are located upstream of the raw material inlets in the direction of the airflow.

[0023] In the third embodiment, the calcination temperature is 750°C, the calcination time is 1.5 h, and the calcination atmosphere is a CO atmosphere.

[0024] In the third embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 20% of activated kaolin to the final product.

[0025] In a fourth embodiment, an air inlet of the decomposition furnace is connected to an extension tube. A distal end of the extension tube of the air inlet is connected to an inlet tube. A tail end of the inlet tube is trumpet-shaped.

[0026] The inlet tube is symmetrically equipped with two raw material inlets. A proximal end of the inlet tube's extension tube is equipped with two fuel ports. A third raw material inlet and a third fuel port are located on the extension tube. The angle between the direction of feed of the third raw material inlet and the third fuel port and the direction of the inlet tube's extension is a right angle. The inlet tube is arranged between the preheater and the decomposition furnace.

[0027] In the fourth embodiment, the calcination temperature is 750°C, the calcination time is 0.5 h to 1.5 h, and the calcination atmosphere is a CO 165 ppm atmosphere.

[0028] In the fourth embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 5% of activated kaolin to the final product.

[0029] In a second aspect, the invention further provides a calcination process for low-carbon cement clinker. The calcination process comprises:

[0030] drying and grinding of a cement and kaolin base material separately, and obtaining a raw cement material and a raw kaolin material;

[0031] adding raw cement material to a cement calcination set for calcination, and generation of cement clinker;

[0032] introduction of raw kaolin material into a kaolin calcination unit for calcination and activation, and generation of activated kaolin;

[0033] adding activated kaolin to the discharge side of the cement calcination assembly according to a predetermined ratio of activated kaolin to cement clinker; and

[0034] cooling of a mixture of cement clinker and activated kaolin by a grid cooler, and obtaining cement clinker containing kaolin.

[0035] In an optional embodiment, the grinding of kaolin includes:

[0036] control, during the grinding of kaolin, of the fineness of the kaolin powder after grinding so that it is 75 qm to 85 qm and sieving of the residues of 4% to 6%.

[0037] In an optional embodiment, the addition of activated kaolin to the discharge side of the cement calcination assembly includes:

[0038] addition of activated kaolin into the discharge port of the cement calcination assembly or into a material inlet of the grid cooler. BRIEF DESCRIPTION OF THE FIGURES

[0039] In order to illustrate more clearly the technical solutions of the specific embodiments of the invention or in the related art, the accompanying figures required for the description of the specific embodiments or the related art are briefly described below. Of course, the accompanying figures in the following description constitute several embodiments of the invention, and a person skilled in the art can create other figures from these accompanying figures without creative effort.

[0040] The [Fig. 1] is a schematic structural diagram of a preheater and decomposition furnace of an example of the invention;

[0041] The [Fig.2] is a schematic structural diagram of a first cyclone cylinder of an example of the invention;

[0042] The [Fig.3] is a schematic structural diagram of a second cyclone cylinder of an example of the invention;

[0043] The [Fig.4] is a schematic structural diagram of a third cyclone cylinder of an example of the invention;

[0044] The [Fig.5] is a schematic structural diagram of a decomposition furnace of example 4 of the invention;

[0045] Description of reference numbers:

[0046] 1, preheater;

[0047] 11, first cyclone cylinder; 111, first air intake cylinder; 1111, first air inlet; 1112, supply port; 112, first cyclone; 1121, first exhaust port; 1122, first discharge port;

[0048] 12, second cyclone cylinder; 121, second air intake cylinder; 1211, second air inlet; 1212, return port; 122, second cyclone; 1221, second exhaust port; 1222, second discharge port;

[0049] 13, third cyclone cylinder; 131, third air intake cylinder; 132, third cyclone; 1321, third exhaust port; 1322, third discharge port;

[0050] 2, decomposition furnace; 21, extension tube; 22, inlet tube; 23, inlet of raw material; 24, fuel addition port. DETAILED DESCRIPTION

[0051] In order to clarify the objectives, technical solutions, and advantages of the examples of the invention, the technical solutions of the examples of the invention are clarified and fully described below in conjunction with the accompanying figures of the examples of the invention. Of course, the examples described are only examples and not all examples of the invention. Based on the examples of the invention, all other examples obtained by a person skilled in the art without creative effort are covered by the scope of protection of the present invention.

[0052] In the description of the present invention, it shall be understood that the orientation or position links denoted by the terms "central," "upper / top," "lower / base," "left," "right," "vertical," "horizontal," "internal," "external," etc., are based on the orientation or position links shown in the Figures and are intended solely to facilitate and simplify the description of the invention, and not to indicate or imply that the device or reference element must have a particular orientation and be constructed or operated in a particular direction; consequently, they cannot be deemed to limit the invention. Furthermore, the terms "first," "second," and "third" are used solely for descriptive purposes and are not deemed to indicate or imply any relative importance.

[0053] In the description of the present invention, it should be explained that, except where clearly specified and defined otherwise, the terms "mounted," "connect," and "connected" are to be interpreted broadly. They may refer, for example, to a fixed connection, a removable connection, or an integral / one-piece connection; a mechanical or electrical connection; a direct connection; an indirect connection via an intermediate support; an internal connection of two elements; a wireless or wired connection. A person skilled in the art can understand the specific meaning of these terms in the context of the present invention based on the particular circumstances.

[0054] Furthermore, the technical features involved in the different embodiments of the invention described below can be combined mutually as long as they do not generate mutual contradiction.

[0055] The main carbon dioxide emissions in cementitious material production processes are generated by the decomposition of carbonate minerals during clinker calcination, which accounts for 60% or more of the carbon dioxide emissions of an entire production process. Therefore, the main measures currently being adopted by the cement industry consist of developing alternative raw materials and energy-saving and emission-reduction technologies. consumption of production processes, as well as reduction of the quantities of clinker used in cement and energy consumption.

[0056] In this regard, the present invention provides a calcination system and method for low carbon cement clinker, in order to solve the problems of using large quantities of clinker in cement and high energy consumption.

[0057] With reference to FIGS. 1-5, examples of the invention are described below.

[0058] In a first aspect, the invention provides a calcination system for low-carbon cement clinker. The calcination system comprises a kaolin calcination unit and a cement calcination unit.

[0059] Specifically, in one example of the invention, the kaolin calcination assembly comprises a preheater 1 and a decomposition furnace 2.

[0060] Furthermore, the preheater 1 is equipped with a multi-stage cyclone cylinder; the preheater 1 has a feed port 1112, a discharge port, and a discharge port. Raw material powder is added from the feed port 1112, and the newly added cold raw material comes into contact with the hot combustion gases of the decomposition furnace 2. By direct heat exchange, the raw material is gradually heated, and during this time, the combustion gas is gradually cooled, so that heat is gradually recovered. In a multi-stage cyclone system, the raw material can pass through the plurality of cyclones sequentially, and the temperature of the raw material can increase once the raw material passes through a cyclone stage.Simultaneously, the temperature of the combustion gases can gradually decrease until the material enters the decomposition furnace 2 via the discharge port. Through the waste port, large and heavy particles of the raw material can be returned to a grinding system for further grinding. After regrinding, the raw material powder can be added back into the preheater 1 via the feed port 1112.

[0061] Furthermore, the decomposition furnace 2 is equipped with a fuel supply port 24 and a raw material inlet 23. The raw material inlet 23 is connected to the discharge port. Activated kaolin is generated by the decomposition furnace 2 via calcination. The decomposition furnace 2 has a calcination temperature of 700°C to 850°C and a calcination time of 0 h to 1.5 h. The calcination atmosphere in the decomposition furnace 2 is an oxygen-enriched atmosphere or a CO-reducing atmosphere.

[0062] Furthermore, the cement calcination unit may be a rotary kiln. The cement calcination unit is configured to generate cement clinker via calcination. Activated kaolin is added to the discharge side of the cement calcination unit. according to a predetermined ratio of activated kaolin to cement clinker. The predetermined ratio can be 5%, 10%, 15%, 20%, etc., for example.

[0063] In the examples of the invention, kaolin is added based on a ratio of raw cement material, so that the amount of carbon-containing raw materials used in clinker production and the carbon emissions from the clinker can be reduced, and the hydration rate of the cement clinker adjusted. Furthermore, the kaolin can be calcined and activated, and at the same time, the calcined kaolin can be added to the discharge side of the cement calcination assembly. For example, by collaboratively cooling the discharge port at the head of a rotary kiln or at the material inlet of a grate cooler, it is possible to save on the total energy consumed and reduce the carbon in the calcination system. In addition, the layered aluminosilicate structure in the kaolin is dehydrated and decomposed at high temperature, and a structural reorganization is achieved.Six-coordinated aluminum ions are transformed into four-coordinated activated alumina, which exhibits higher chemical reaction activity. Some silicon-oxygen bonds in the layered structure are broken, resulting in the formation of island-like active silicon oxide, further enhancing material activity. Furthermore, by increasing specific surface areas and changing the average diameter and hole size, the surface area of ​​the material expands, and its internal structure becomes more porous, thus improving contact areas with other substances and reaction efficiency. Consequently, the active sites on the surface and structure of the cement clinker can be increased, and the performance of the final cement product can be significantly improved.For example, cohesive strength can be increased, durability improved, or other physical or chemical properties can be adjusted.

[0064] Furthermore, in an optional embodiment, the preheater 1 is equipped with a three-stage cyclone cylinder comprising a first cyclone cylinder 11, a second cyclone cylinder 12 and a third cyclone cylinder 13.

[0065] In an example of the invention, the first cyclone cylinder 11 is provided with a first air inlet cylinder 111 and two first cyclones 112 arranged in parallel to a tail termination of the first air inlet cylinder 111. The first air inlet cylinder 111 is provided with a first air inlet 1111 and the supply port 1112. The top of the first cyclone 112 is provided with a first exhaust port 1121. The base of the first cyclone 112 is provided with a first discharge port 1122.

[0066] In addition, the second cyclone cylinder 12 is provided with a second air inlet cylinder 121 and a second cyclone 122 connected to a tail termination of the second air inlet cylinder 121. The second air inlet cylinder 121 is provided with a second air inlet 1211 and a pair of return ports 1212. The top of the second cyclone 122 is provided with a second exhaust port 1221. The base of the second cyclone 122 is provided with a second discharge port 1222.

[0067] Regarding the connection method of the second cyclone cylinder 12, the pair of return ports 1212 is connected to the first two discharge ports 1122 respectively. The second exhaust port 1221 is connected to the first air inlet 1111, and the second discharge port 1222 constitutes the discharge port of the preheater 1.

[0068] In addition, the third cyclone cylinder 13 is provided with a third air inlet cylinder 131 and a third cyclone 132. One end of the third air inlet cylinder 131 communicates with a flue gas outlet of the decomposition furnace 2, and the other end of the third air inlet cylinder 131 is connected to the third cyclone 132. The top of the third cyclone 132 is provided with a third exhaust port 1321. The base of the third cyclone 132 is provided with a third discharge port 1322. The third discharge port 1322 constitutes the waste port of the preheater 1.

[0069] Regarding the connection method of the third cyclone cylinder 13, the third exhaust port 1321 is connected to the second air inlet 1211, and the waste is discharged through the third discharge port 1322.

[0070] In order to illustrate the invention and to better understand the technical solutions and advantages, the invention is described in detail by examples and Figures, and the invention is not limited by the following examples. Example 1:

[0071] In a first embodiment, the decomposition furnace 2 has a calcination temperature of 750°C and a calcination time of 1 h, and the calcination atmosphere in the decomposition furnace 2 is an oxygen-enriched atmosphere. The chemical composition of kaolin is shown in Table 1. [Table 1] Raw material: CaO, SiO2, Al2O3, Fe2O3, MgO, SO3, K2O, Na2O. Losses: Kaolin 1.83, 64.25, 14.58, 4.20, 1.83, 2.20, 2.76, 0.21, 8.14

[0072] Table 1 Chemical composition of kaolin

[0073] In the first embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 10% of activated kaolin to the final product.

[0074] An addition position is located at a material inlet of a grid cooler. In accordance with GB / T 17671-2021 "Test process for cement mortar (ISO process)", the flexural and compressive strength of the cement clinker produced containing kaolin at 3 days, 7 days and 28 days are measured; the results are shown in Table 2. [Table 2] Curing time (days) Strength (MPa) O2 concentration (%) 5 10 20 30 3 Flexure 8.7 9.0 9.5 9.8 Compression 29.1 32.2 34.3 34.5 7 Flexure 9.8 10.4 10.2 10.9 Compression 35.0 38.2 39.5 40.0 28 Flexure 11.9 12.2 12.5 12.5 Compression 45.3 47.6 48.7 49.3

[0075] Table 2 Results of resistance measurements of cement clinker containing calcined kaolin in a eutrophic atmosphere. Example 2:

[0076] In a second embodiment, an area of ​​the second exhaust port 1221 of the second cyclone 122 is 1.4 m² to 1.6 m², and a height of an external cylinder of the second cyclone 122 is 1.9 m to 2.1 m. The decomposition furnace 2 is provided with two fuel addition ports 24 and a single raw material inlet 23. The fuel addition ports 24 are located on one side of the raw material inlet 23. In the second embodiment, the calcination temperature is 700°C to 850°C, the calcination time is 1 h, and the calcination atmosphere in Decomposition furnace 2 is a CO atmosphere. The chemical composition of kaolin is shown in Table 3. [Table 3] Raw material CaO SiO2 AI2O3 Fe2O3 MgO so3 k2o Na2O Losses Kaolin 1.65 62.15 15.36 4.36 2.05 1.68 2.14 0.36 10.25

[0077] Table 3 Chemical composition of kaolin

[0078] In the second embodiment, activated kaolin is added to the cement calcination assembly at a mass ratio of 15% of activated kaolin to the final product. An addition point is located at a discharge port of the kiln head. In accordance with GB / T 17671-2021 "Test process for cement mortar" (ISO process) », the flexural and compressive strength of the cement clinker produced containing kaolin at 3 days, 7 days and 28 days are measured, the results are shown in Table 4. [Table 4] Curing time (days) Strength (MPa) Calcination temperature (°C) 700 750 800 850 3 Flexural strength 10.1 9.8 10.0 10.2 Compression 32.7 32.3 34.5 34.1 7 Flexural strength 10.9 11.7 10.8 11.2 Compression 39.1 39.8 41.7 37.3 28 Flexural strength 12.9 12.9 13.3 13.4 Compression 46.3 49.6 50.4 49.4

[0079] Table 4 Results of resistance measurements of cement clinker containing calcined kaolin at different temperatures Example 3:

[0080] In a third embodiment, compared with the first two examples, the size of each cyclone cylinder stage is increased. A CO-reducing tube is additionally arranged between the second air inlet 1211 and the third exhaust port 1321 of the third cyclone 132. The decomposition furnace 2 is provided with three fuel addition ports 24 and three raw material inlets 23. The fuel addition ports 24 are oriented facing the opposite side of the raw material inlets 23. The fuel addition ports 24 are located upstream of the raw material inlets 23 in the direction of the airflow.

[0081] In the third embodiment, the calcination temperature is 750°C, the calcination time is 1.5 h, and the calcination atmosphere is a CO atmosphere. The chemical composition of kaolin is shown in Table 5. [Table 5] Raw material CaO SiO2 A12O3 Fe2O3 MgO SO3 k2o Na2O Losses Kaolin 2.24 65.17 13.28 4.15 1.95 2.36 2.55 0.18 8.12

[0082] Table 5 Chemical composition of kaolin

[0083] In the third embodiment, activated kaolin is added to the cement calcination process at a mass ratio of 20% of activated kaolin to the final product. An addition point is located at a discharge port of the kiln head. In accordance with GB / T 17671-2021 "Test procedure for cement mortar (ISO procedure)," the flexural and compressive strength of the cement clinker is determined. Products containing kaolin were measured at 3 days, 7 days, and 28 days; the results are shown in Table 6. [Table 6] Curing time (days) Strength (MPa) CO concentration (ppm) 100 165 200 400 3 Flexural strength 8.9 9.1 8.5 8.4 Compression 29.2 28.9 26.8 26.2 7 Flexural strength 9.6 9.7 9.4 9.3 Compression 34.5 33.7 31.5 30.1 28 Flexural strength 11.5 12.5 11.3 10.9 Compression 46.7 48.2 44.2 41.2

[0084] Table 6 Results of resistance measurements of cement clinker containing calcined kaolin in a reducing atmosphere Example 4:

[0085] In a fourth embodiment, an air inlet of the decomposition furnace 2 is connected to an extension tube 21. A distal end of the extension tube 21 of the air inlet is connected to an inlet tube 22. A tail end of the inlet tube 22 is trumpet-shaped. The inlet tube 22 is symmetrically provided with two raw material inlets 23. A proximal end of the extension tube 21 of the inlet tube 22 is provided with two fuel addition ports 24. A third raw material inlet 23 and a third fuel addition port 24 are located on the extension tube 21. An included angle between the direction of feed of the third raw material inlet 23 and the third fuel addition port 24 and the direction of extension of the feed tube is a right angle. The feed tube is arranged between the preheater 1 and the decomposition furnace 2.

[0086] In the fourth embodiment, the calcination temperature is 750°C, the calcination time is 0.5 h to 1.5 h, and the calcination atmosphere is a CO₂ atmosphere at 165 ppm. The chemical composition of kaolin is shown in Table 7. [Table 7] Raw material: CaO, SiO2, Al2O3, Fe2O3, MgO, SO3, K2O, Na2O. Losses: Kaolin 3.25, 61.57, 16.28, 3.98, 1.66, 1.79, 2.48, 0.28, 8.71

[0087] Table 7 Chemical composition of kaolin

[0088] In the fourth embodiment, the activated kaolin is added to the set of cement calcination according to a mass ratio of 5% of activated kaolin to the product final. An addition position is located at a material inlet of the grid cooler. In accordance with GB / T 17671-2021 "Test procedure for cement mortar (ISO procedure)", the flexural and compressive strength of the cement clinker produced containing kaolin at 3 days, 7 days and 28 days are measured; the results are shown in Table 8. [Table 8] Curing time (days) Strength (MPa) Time (h) 0.5 1 1.5 3 Flexure 8.8 9.2 9.5 Compression 31.5 33.7 34.3 7 Flexure 9.5 10.5 10.9 Compression 36.7 39.2 40.5 28 Flexure 10.8 12.1 12.5 Compression 46.5 48.2 50.3

[0089] Table 8 Results of measurements of the resistances of kaolin-containing cement clinker at different calcination times

[0090] In a second aspect, the invention further provides a calcination process for low-carbon cement clinker. The calcination process comprises the following steps:

[0091] SI, drying and grinding of a cement and kaolin base material separately, and obtaining a raw cement material and a raw kaolin material;

[0092] S2, addition of raw cement material to a cement calcination set for calcination, and generation of cement clinker;

[0093] S3, introduction of raw kaolin material into a calcination unit kaolin for calcination and activation, and generation of activated kaolin;

[0094] S4, addition of activated kaolin to the discharge side of the calcination assembly cement according to a predetermined ratio of activated kaolin to cement clinker; and

[0095] S5, cooling of a mixture of cement clinker and kaolin activated by a grate cooler, and obtaining cement clinker containing kaolin.

[0096] Furthermore, in an optional embodiment, the kaolin grinding step includes the following step:

[0097] control, during the grinding of the kaolin, of the fineness of the kaolin powder after grinding so that it is 75 qm to 85 qm and sieving of the residues of 4% to 6%.

[0098] Furthermore, in an optional embodiment, the step in which the activated kaolin is added to the discharge side of the cement calcination assembly includes the following step:

[0099] addition of activated kaolin into the discharge port of the cement calcination assembly or into a material inlet of the grid cooler.

[0100] Although the examples of the invention are described in relation to the Figures, a person skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and said modifications and variations are all covered by the scope defined in the supplementary claims.

Claims

Demands

1. Calcination device for low carbon cement clinker, comprising: a kaolin calcination unit including a preheater (1) and a decomposition kiln (2), wherein the preheater (1) is provided with a multi-stage cyclone cylinder; the preheater (1) is provided with a feed port (1112) and a discharge port; the decomposition kiln (2) is provided with a fuel addition port (24) and a raw material inlet (23); the raw material inlet (23) is connected to the discharge port; the decomposition kiln (2) is used for calcination and to generate activated kaolin; and the decomposition furnace (2) is configured to be suitable for calcination at a temperature of 700°C to 850°C, with a calcination time of 0 h to 1.5 h, and the calcination atmosphere being an oxygen-enriched atmosphere or a CO-reducing atmosphere;and a cement calcination set configured to generate cement clinker via calcination, wherein the cement calcination set includes a discharge side, the discharge side being used to add activated kaolin at a predetermined ratio of activated kaolin to the cement clinker.

2. A calcination device according to claim 1, wherein the preheater (1) is provided with a three-stage cyclone cylinder comprising a first cyclone cylinder (11), a second cyclone cylinder (12) and a third cyclone cylinder (13); the first cyclone cylinder (11) is provided with a first air inlet cylinder (111) and two first cyclones (112) arranged in parallel to a tail termination of the first air inlet cylinder (111), and the first air inlet cylinder (111) is provided with a first air inlet (1111) and the feed port (1112); and the top of the first cyclone (112) is provided with a first exhaust port (1121), and the base of the first cyclone (112) is provided with a first discharge port (1122); the second cyclone cylinder (12) is equipped with a second air inlet cylinder (121) and a second cyclone (122) connected to a tail termination of the second air inlet cylinder (121); and the second air inlet cylinder (121) is provided with a second air inlet (1211) and a pair of return ports (1212), the top of the second cyclone (122) is provided with a second exhaust port (1221), and the base of the second cyclone (122) is provided with a second discharge port (1222); the pair of return ports (1212) is connected to the first two discharge ports (1122) respectively; and the second exhaust port (1221) is connected to the first air inlet (1111), and the second discharge port (1222) constitutes the discharge port of the preheater (1); the third cyclone cylinder (13) is equipped with a third air inlet cylinder (131) and a third cyclone (132);One termination of the third air inlet cylinder (131) communicates with a fume outlet of the decomposition furnace (2), and the other termination of the third air inlet cylinder (131) is connected to the third cyclone (132); and the top of the third cyclone (132) is provided with a third exhaust port (1321), and the base of the third cyclone (132) is provided with a third discharge port (1322); and the third exhaust port (1321) is connected to the second air inlet (1211), and the waste is discharged through the third discharge port (1322).

3. Calcination device according to claim 2, wherein the decomposition furnace (2) is configured to be suitable for calcination at a temperature of 750°C, with a calcination time of 1 h, and the calcination atmosphere being an oxygen-enriched atmosphere.

4. Calcination device according to claim 3, wherein the cement calcination assembly is configured to add activated kaolin which represents a mass ratio of 10% to the final product.

5. A calcination device according to claim 2, wherein an area of ​​the second exhaust port (1221) of the second cyclone (122) is 1.4 m² to 1.6 m², and a height of an outer cylinder of the second cyclone (122) is 1.9 m to 2.1 m; and the decomposition furnace (2) is provided with two fuel addition ports (24) and a single raw material inlet (23), and the addition ports fuel (24) are located on one side of the raw material inlet (23).

6. Calcination device according to claim 5, wherein the decomposition furnace (2) is configured to be suitable for calcination at a temperature of 700°C to 850°C, with a calcination time of 1 h, and the calcination atmosphere being a CO atmosphere.

7. Calcination device according to claim 6, wherein the cement calcination assembly is configured to add activated kaolin which represents a mass ratio of 15% to the final product.

8. Calcination device according to claim 2, wherein a CO reducing tube is further arranged between the second air inlet (1211) and the third exhaust port (1321) of the third cyclone (132); and the decomposition furnace (2) is provided with three fuel addition ports (24) and three raw material inlets (23), the fuel addition ports (24) are oriented facing the opposite side of the raw material inlets (23), and the fuel addition ports (24) are located upstream of the raw material inlets (23) in the direction of the airflow.

9. Calcination device according to claim 8, wherein the decomposition furnace (2) is configured to be suitable for calcination at a temperature of 750°C, with a calcination time of 1.5 h, and the calcination atmosphere being a CO atmosphere.

10. Calcination device according to claim 9, wherein the cement calcination assembly is configured to add activated kaolin which represents a mass ratio of 20% to the final product.

11. A calcination device according to claim 2, wherein an air inlet of the decomposition furnace (2) is connected to an extension tube (21), a distal end of the extension tube (21) of the air inlet is connected to an inlet tube (22), and a tail end of the inlet tube (22) is trumpet-shaped; the inlet tube (22) is symmetrically provided with two raw material inlets (23), a proximal end of the extension tube (21) of the inlet tube (22) is provided with two fuel addition ports (24), a third raw material inlet (23) and a third fuel addition port (24) are located on the tube. extension (21), and an angle included between the direction of feed of the third raw material inlet (23) and the third fuel addition port (24) and the direction of extension of the feed tube is a right angle; and the feed tube is arranged between the preheater (1) and the decomposition furnace (2).

12. Calcination device according to claim 11, wherein the decomposition furnace (2) is configured to be suitable for calcination at a calcination temperature of 750°C, with the calcination time of 0.5 h to 1.5 h, and the calcination atmosphere being a CO 165 ppm atmosphere.

13. Calcination device according to claim 12, wherein the cement calcination assembly is configured to add activated kaolin which represents a mass ratio of 5% to the final product.

14. A calcination process for low-carbon cement clinker, comprising: drying and grinding a cement and kaolin base material separately, and obtaining a cement raw material and a kaolin raw material; adding the cement raw material to a cement calcination set for calcination, and generating cement clinker; introducing the kaolin raw material into a kaolin calcination set for calcination and activation, and generating activated kaolin; adding the activated kaolin to the discharge side of the cement calcination set according to a predetermined ratio of activated kaolin to cement clinker; and cooling a mixture of cement clinker and activated kaolin by a grid chiller, and obtaining cement clinker containing kaolin.

15. Calcination process according to claim 14, wherein the grinding of the kaolin includes: checking, during the grinding of the kaolin, the fineness of the kaolin powder after grinding so that it is from 75 qm to 85 qm and sieving the residues from 4% to 6%.

16. A calcination process according to claim 14 or 15, wherein the addition of activated kaolin to the discharge side of the cement calcination assembly comprises: addition of activated kaolin in the discharge port of the cement calcination unit or in a material inlet of the grid cooler.

Images