A device for preparing auxiliary cementitious material from multi-stage activated coal gangue

Abstract

This utility model discloses a device for preparing auxiliary cementitious materials from multi-stage activated coal gangue, comprising a hot flue gas system, a grinding unit, and a thermal activation unit. The hot flue gas system draws hot flue gas from the thermal activation unit and sends it to the grinding unit. The thermal activation unit includes an activation furnace for activating the coal gangue and a preheater for preheating the coal gangue. The grinding unit includes a grinder, a cyclone separator, and a first bag filter. After mechanical activation by the grinder, the coal gangue is separated by the cyclone separator and the first bag filter. Coarse particles enter the bottom of the activation furnace via the preheater, while fine particles directly enter the bottom of the activation furnace. This device for preparing auxiliary cementitious materials from multi-stage activated coal gangue can activate coal gangue, transforming it into an auxiliary cementitious material with pozzolanic properties, which can be used as a substitute for clinker.

Description

Technical Field

[0001] This utility model relates to the field of cement production, specifically to a device for preparing auxiliary cementitious materials from multi-stage activated coal gangue. Background Technology

[0002] The Cement Industry Energy Conservation and Carbon Reduction Special Action Plan proposes to encourage low clinker coefficient cement, because every ton reduction in clinker production can reduce CO2 emissions by about 0.85 tons.

[0003] GB / T29162-2012, "Classification of Coal Gangue," defines coal gangue as rock with a dry basis ash content >50%, generated during coal mine construction, development, mining, and coal washing. Currently, cement plants mainly utilize its silica-alumina components in raw meal blending, typically at a rate of 3-5%, resulting in limited processing capacity. If coal gangue were to replace 30% of clinker with auxiliary cementitious materials, CO2 emissions could be reduced by 2,550 tons per 10,000 tons of cement. Therefore, there is an urgent need to address how to increase the proportion of coal gangue in raw meal without compromising the mechanical and workability properties of cement. Utility Model Content

[0004] The purpose of this invention is to provide a device for preparing auxiliary cementitious materials from multi-stage activated coal gangue. This device can activate coal gangue to make it into an auxiliary cementitious material with pozzolanic properties, which can be used to replace clinker.

[0005] To achieve the above objectives, this utility model provides a device for preparing auxiliary cementitious materials from multi-stage activated coal gangue, including a hot flue gas system, a grinding unit, and a thermal activation unit. The hot flue gas system draws hot flue gas from the thermal activation unit and sends it into the grinding unit.

[0006] The thermal activation unit includes an activation furnace for activating coal gangue and a preheater for preheating coal gangue.

[0007] The grinding unit includes a grinder, a cyclone separator, and a first bag filter. After the coal gangue is mechanically activated by the grinder, it is separated by the cyclone separator and the first bag filter. Coarse particles enter the bottom of the activation furnace through the preheater, while fine particles enter the bottom of the activation furnace directly.

[0008] Preferably, the thermal activation unit further includes a sorting device connected to the outlet of the activation furnace to screen the activated products. Products with high density are sent into the air inlet pipe at the bottom of the activation furnace, while products with low density are sent into a rapid cooling device for cooling.

[0009] Preferably, the preheater includes at least two stages of cyclones, the primary cyclone includes multiple cyclones connected in parallel, and the remaining stages of cyclones are configured as multiple cyclones connected in series.

[0010] Preferably, the quenching equipment includes an equipment body and a cooling fan. The equipment body is provided with a cold air inlet, a product inlet and an outlet. The cooling fan is connected to the cold air inlet, the product inlet is connected to the sorting equipment, and the outlet is connected to the first filter.

[0011] Preferably, the solid obtained from the first filter is sent to the finished product warehouse to replace the clinker, and the gas filtered by the first filter is sent to the activation furnace.

[0012] Preferably, a cyclone dust collector is installed between the sorting equipment and the quenching equipment. The dust collection port of the cyclone dust collector is connected to the quenching equipment, and the outlet of the cyclone dust collector is connected to the inlet of the last stage cyclone.

[0013] Preferably, the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes a preheating boiler, a denitrification device, and a desulfurization device. The preheating boiler, denitrification device, and desulfurization device utilize waste heat, perform denitrification treatment, and desulfurization treatment on the exhaust gas discharged from the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue.

[0014] Preferably, the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes an end bag filter connected to the outlet of the desulfurization unit, and the dust filtered by the end bag filter is sent to the bottom of the activation furnace.

[0015] According to the above technical solution, the coal gangue of this utility model is mechanically activated by a grinding mill. Mechanical activation can increase the specific surface area of ​​the coal gangue and increase the defects on the surface of its particles, thereby improving the activity of the coal gangue.

[0016] Mechanically activated coal gangue is then sent to a thermal activation unit for thermal activation. Thermal activation can reduce the carbon content in the coal gangue, thus avoiding the impact of carbon in the coal gangue on the mechanical and workability properties of cement. On the other hand, it can remove the crystal water of clay minerals in the coal gangue, destroy the crystal structure, and give it pozzolanic properties.

[0017] After mechanical and thermal activation treatment, the silica and aluminum components of coal gangue are transformed into pozzolanic materials, such as amorphous SiO2 and Al2O3. During cement hydration, these materials can undergo secondary reactions with Ca(OH)2, a clinker hydration product, to generate CSH gel and other cementitious phases. CSH gel can compensate for the strength loss caused by reduced clinker content, ensuring the mechanical properties of cement. Therefore, pozzolanic materials can be used as a significant substitute for clinker. Studies have shown that coal gangue, after mechanical and thermal activation treatment, can replace 20-40% of the clinker.

[0018] Therefore, the equipment for preparing auxiliary cementitious materials using multi-stage activated coal gangue can turn coal gangue into auxiliary cementitious materials with pozzolanic activity, which can replace clinker and thus effectively reduce the amount of clinker used in cement.

[0019] The grinding unit primarily grinds coal gangue, achieving preliminary mechanical activation. During the crushing process, the organic matter and minerals in the coal gangue are separated due to differences in density or hardness. Generally, fine particles are enriched with softer organic matter, have lower ash content, and higher calorific value. Coarse particles contain more hard minerals, have higher ash content, and lower calorific value.

[0020] Two-stage dust collection devices are installed after the grinding unit. The primary stage uses a cyclone separator, and the final stage uses a first bag filter. The cyclone separator collects coarse particles, and the first bag filter collects fine particles.

[0021] After entering the grinding unit, the hot flue gas carries the solid particles from the grinding unit through pipelines into the cyclone separator 22 for separation. Inside the cyclone separator, fine coal gangue particles flow out of the outlet with the hot flue gas, while coarse coal gangue particles are collected and discharged through the dust collection port, thus achieving the separation of fine and coarse coal gangue particles. The hot flue gas containing fine particles is collected by the first bag filter. The collected fine coal gangue particles can be directly sent to the activation furnace, while the coarse coal gangue particles collected by the cyclone separator enter the preheater, are heated by the preheater, and then sent to the activation furnace.

[0022] The activation temperature of coal gangue generally does not exceed 850℃. Above this temperature, highly reactive clay-like substances will form inert mullite crystals, significantly reducing the activity of the coal gangue. Simultaneously, the activation temperature of coal gangue should not be lower than 600℃. Below this temperature, the activation efficiency of coal gangue is low, or the activation furnace cannot reliably activate the coal gangue. Therefore, thermal activation requires strict control of the temperature range between 650 and 800℃.

[0023] Fine-grained coal gangue has a large specific surface area, making it easier to heat up during contact with hot flue gas. However, coarse-grained coal gangue cannot be heated up in time during contact with hot flue gas. If coarse-grained coal gangue is fed into the activation furnace, it will cause temperature fluctuations in the activation furnace, affecting the stability of the activation process of coal gangue.

[0024] Before coarse coal gangue enters the activation furnace, it is preheated by a preheater so that the temperature of the coarse coal gangue entering the activation furnace is close to the temperature of the activation furnace 31, thus avoiding temperature fluctuations in the activation furnace and ensuring the activation effect of the activation furnace on the coal gangue.

[0025] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the following detailed description to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 This is a schematic diagram of a device for preparing auxiliary cementitious materials from multi-stage activated coal gangue;

[0028] Figure 2 This is a schematic diagram of a rapid cooling device.

[0029] Explanation of reference numerals in the attached figures

[0030] 31 Activation Furnace 21 Grinding Mill

[0031] 22 Cyclone 32 Sorting Equipment

[0032] 11 Air inlet duct 33 Rapid cooling equipment

[0033] 331 Equipment body; 332 Cooling fan

[0034] 3311 Cold air inlet; 3312 Product inlet

[0035] 3313 Export 4 First Filter

[0036] 341 Primary Cyclone Entrainer 342 Advanced Cyclone Entrainer

[0037] 320 Cyclone Dust Collector 5 Desulfurization Unit

[0038] 6. Terminal bag filter 23. First bag dust collector

[0039] 7. Denitrification unit; 8. Waste heat boiler

[0040] 333 Cooling Fan

[0041] 332 standby fan Detailed Implementation

[0042] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0043] In this utility model, unless otherwise stated, directional terms such as "one end," "the other end," and "bottom" in the terminology only represent the orientation of the term in its normal use or are common terms understood by those skilled in the art, and should not be regarded as a limitation on the term.

[0044] See Figure 1 The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue includes a hot flue gas system, a grinding unit, and a thermal activation unit. The hot flue gas system draws hot flue gas from the thermal activation unit and sends it into the grinding unit.

[0045] The thermal activation unit includes an activation furnace 31 for activating coal gangue and a preheater for preheating coal gangue.

[0046] The grinding unit includes a grinder 21, a cyclone separator 22, and a first bag dust collector 23. After the coal gangue is mechanically activated by the grinder 21, it is separated by the cyclone separator 22 and the first bag dust collector 23. The coarse particles enter the bottom of the activation furnace 31 through the preheater, while the fine particles enter the bottom of the activation furnace 31 directly.

[0047] Through the implementation of the above technical solution, coal gangue is mechanically activated by the grinding mill 21. Mechanical activation can increase the specific surface area of ​​coal gangue and increase the defects on the surface of its particles, thereby improving the activity of coal gangue.

[0048] Mechanically activated coal gangue is then sent to a thermal activation unit for thermal activation. Thermal activation can reduce the carbon content in the coal gangue, thus avoiding the impact of carbon in the coal gangue on the mechanical and workability properties of cement. On the other hand, it can remove the crystal water of clay minerals in the coal gangue, destroy the crystal structure, and give it pozzolanic properties.

[0049] After mechanical and thermal activation treatment, the silica and aluminum components of coal gangue are transformed into pozzolanic materials, such as amorphous SiO2 and Al2O3. During cement hydration, these materials can undergo secondary reactions with Ca(OH)2, a clinker hydration product, to generate CSH gel and other cementitious phases. CSH gel can compensate for the strength loss caused by reduced clinker content, ensuring the mechanical properties of cement. Therefore, pozzolanic materials can be used as a significant substitute for clinker. Studies have shown that coal gangue, after mechanical and thermal activation treatment, can replace 20-40% of the clinker.

[0050] Therefore, the equipment for preparing auxiliary cementitious materials using multi-stage activated coal gangue can turn coal gangue into auxiliary cementitious materials with pozzolanic activity, which can replace clinker and thus effectively reduce the amount of clinker used in cement.

[0051] The grinding unit primarily grinds coal gangue, achieving preliminary mechanical activation. During the crushing process, the organic matter and minerals in the coal gangue are separated due to differences in density or hardness. Generally, fine particles are enriched with softer organic matter, have lower ash content, and higher calorific value. Coarse particles contain more hard minerals, have higher ash content, and lower calorific value.

[0052] Two-stage dust collection devices are installed after the grinding unit. The primary stage uses a cyclone separator 22, and the final stage uses a first bag dust collector 23. The cyclone separator 22 collects coarse particles, and the first bag dust collector 23 collects fine particles.

[0053] After entering the grinding unit, the hot flue gas carries the solid particles from the grinding unit through pipelines into the cyclone separator 22 for separation. Inside the cyclone separator, fine coal gangue particles flow out of the outlet with the hot flue gas, while coarse coal gangue particles are collected and discharged through the dust collection port, thus achieving the separation of fine and coarse coal gangue particles. The hot flue gas containing fine particles is collected by the first bag filter 23. The collected fine coal gangue particles can be directly sent to the activation furnace 31, while the coarse coal gangue particles collected by the cyclone separator 22 enter the preheater, are heated by the preheater, and then sent to the activation furnace 31.

[0054] The activation temperature of coal gangue generally does not exceed 850℃. Above this temperature, highly reactive clay-like substances will form inert mullite crystals, significantly reducing the activity of the coal gangue. Simultaneously, the activation temperature of coal gangue should not be lower than 600℃. Below this temperature, the activation efficiency of coal gangue is low, or the activation furnace 31 cannot reliably activate the coal gangue. Therefore, thermal activation requires strict control of the temperature range between 650 and 800℃.

[0055] Fine-grained coal gangue has a large specific surface area, making it easier to heat up during contact with hot flue gas. However, coarse-grained coal gangue cannot be heated up in time during contact with hot flue gas. If coarse-grained coal gangue is fed into the activation furnace 31, it will cause temperature fluctuations in the activation furnace 31, affecting the stability of the activation process of coal gangue in the activation furnace 31.

[0056] Before coarse coal gangue enters the activation furnace 31, it is preheated by a preheater so that the temperature of the coarse coal gangue entering the activation furnace 31 is close to the temperature of the activation furnace 31, thus avoiding temperature fluctuations in the activation furnace 31 and ensuring the activation effect of the activation furnace 31 on the coal gangue.

[0057] In this embodiment, preferably, the thermal activation unit further includes a sorting device 32, which is connected to the outlet of the activation furnace 31 to screen the activated products. Products with high density are sent into the air inlet pipe 11 at the bottom of the activation furnace 31, while products with low density are sent into the rapid cooling device 33 for cooling.

[0058] The sorting equipment 32 uses gravity separation to screen the coal gangue product discharged from the activation furnace 31. The bulk density of the uncalcined and unactivated coal gangue is typically 1.4–1.8 g / cm³. 3 In most cases, the density of activated coal gangue decreases after calcination, typically ranging from 1.2 to 1.3 g / cm³. 3Based on the different densities of materials in different states, gravity separation is used to promptly separate incompletely activated materials from the product exiting the activation furnace 31 and return them to the activation furnace 31. After being separated, the incompletely activated materials are fed into the air inlet pipe 11 at the inlet of the activation furnace 31 via a feeding pipe. The air inlet pipe 11 contains hot flue gas that is being supplied to the activation furnace 31. The incompletely activated materials, along with the hot flue gas, enter the activation furnace 31 in this air inlet pipe 11 and continue to undergo high-temperature activation. This method of re-feeding the materials into the activation furnace 31 effectively increases the residence time of the incompletely activated materials within the furnace, thereby increasing the activation probability of the coal gangue.

[0059] The suspension calcination activation furnace 31 is adopted, and an internal spray structure can be designed to increase the dispersion of materials and improve the activation rate. The heat source inside the activation furnace 31 mainly comes from external heat sources and the heat generated by the spontaneous combustion of coal gangue.

[0060] Preferably, the cyclone dust collector 320 separates the coal gangue product separated by the sorting equipment 32 from the hot flue gas. The separated coal gangue product with lower density is collected through the dust collection port and sent to the quenching equipment 33 for cooling. The cooled coal gangue product is easier to transport and store. The separated hot flue gas then enters the preheater to preheat the coarse coal gangue particles in it.

[0061] In this embodiment, preferably, the preheater includes at least two stages of cyclones, the primary cyclone 341 includes a plurality of parallel cyclones 22, and the stage cyclones 22 are configured as a plurality of cyclones 22 connected in series.

[0062] The hot flue gas discharged from the outlet of the activation furnace 31 is separated by the cyclone dust collector 320 and enters the preheater through the advanced cyclone 342 to dry the coarse coal gangue in the preheater. The hot gas enters the preheater and gradually moves upward through the last stage cyclone until it is discharged from the outlet of the primary cyclone 341, while the coarse coal gangue enters from the inlet of the first cyclone 341 and gradually moves to the last stage cyclone, where it is finally collected and sent to the activation furnace 31.

[0063] By setting up a preheater with multiple cyclone separators connected in series and parallel, the concentration of dust at the outlet can be effectively reduced. After activation, the coal gangue product is quite fine, making it difficult for cyclones to collect under normal circumstances. If the amount of this discharged material is large, the content of fine coal gangue particles in the hot flue gas system will increase, raising the dust collection pressure of the first bag filter 23 and potentially increasing the processing load on the cement kiln system. Therefore, by progressively improving dust separation efficiency through multiple cyclone separators connected in series, the amount of discharged material can be effectively reduced.

[0064] Coarse-grained coal gangue typically contains more hard minerals, resulting in a higher SiO2 content in the ash. Because clay minerals are easily broken, they accumulate Al2O3, leading to higher SiO2 and Al2O3 content in the fine-grained ash of the hot flue gas. However, these fine particles are relatively difficult to collect, and if a large amount of fine powder is discharged from the system, it will inevitably reduce product activity. Therefore, the preheater is designed with a cyclone separator in series and parallel. The primary cyclone separator 341 is a high-efficiency cyclone separator, mainly collecting slightly finer dust to reduce system ash return, and is preferably designed as multiple high-efficiency cyclone separators in parallel. The advanced cyclone separator 342 mainly collects slightly coarser particles and also serves a heat exchange function; preferably, it is designed as multiple cyclone separators in series, which can increase heat exchange time and improve the preheating effect of the preheater while achieving the collection of slightly coarser particles.

[0065] In this embodiment, preferably, the quenching device 33 includes a device body 331 and a cooling fan 333. The device body 331 is provided with a cold air inlet 3311, a product inlet 3312 and an outlet 3313. The cooling fan 333 is connected to the cold air inlet 3311, the product inlet 3312 is connected to the sorting device 32, and the outlet 3313 is connected to the first filter 4.

[0066] The quenching device 33 adopts a double-sided air intake method to achieve the effect of "cold air carrying hot material" and prevent the material from "sticking to the wall". Two cold air inlets 3311 are set, located at two opposite positions on the main body of the device 331. After the coal gangue product enters the main body of the device 331 through the product inlet 3312, it is held by the cold air on both sides and moves upward with the cold air, and is finally discharged through the outlet 3313.

[0067] Meanwhile, a backup fan 332 is configured to be turned on when "material collapse" occurs inside the equipment body 331. After the material is cooled, it enters the first filter 4 for collection. The first filter 4 can be a bag filter or a multi-stage series-parallel cyclone separator. Finally, the collected activated coal gangue product is stored in the finished product warehouse.

[0068] In this embodiment, preferably, the solid obtained from the first filter 4 is sent to the finished product warehouse to replace the clinker, and the gas filtered by the first filter 4 is sent to the activation furnace 31.

[0069] The gas obtained after filtration by the first filter 4 is air that has already been heated by heat exchange with the high-temperature coal gangue product. Therefore, the hot air filtered by the first filter 4 can be sent into the activation furnace 31 to avoid affecting the temperature of the cremation furnace 31. On the other hand, the oxygen in the hot air can help combustion in the activation furnace 31. This hot air enters the activation furnace 31 through the air inlet pipe 11, and at the same time, it can send the incompletely activated material in the air inlet pipe 11 into the activation furnace 31.

[0070] The flue gas discharged from the outlet of the activation furnace 31 is separated, and the hot gas enters the preheater to heat the granular coal gangue. Finally, it is discharged from the outlet of the first cyclone 341.

[0071] The volatile components in the coal gangue will burn inside the primary cyclone separator, resulting in a high temperature at the outlet of the first cyclone separator 341, which is generally greater than 600°C. Preferably, a waste heat boiler 8 is added to utilize the waste heat from the exhaust gas discharged from the first cyclone separator 341 to achieve heat energy recovery.

[0072] Fuel-type nitrogen in coal gangue can generate fuel-type NOx. Therefore, the exhaust gas discharged from the first cyclone 341 will contain a certain amount of nitrogen oxides. In order to prevent nitrogen oxide emissions from exceeding the standard, a denitrification device 7 is added after the waste heat boiler to reduce the nitrogen oxide content in the exhaust gas.

[0073] The denitrification treated exhaust gas can be sent to the grinding unit through the hot flue gas system, or it can be directly sent to the desulfurization unit 8 and then to the exhaust gas discharge system.

[0074] In this embodiment, preferably, a cyclone dust collector 320 is provided between the sorting device 32 and the quenching device 33, the dust collection port of the cyclone dust collector 320 is connected to the quenching device 33, and the outlet of the cyclone dust collector 320 is connected to the inlet of the advanced cyclone duct 342.

[0075] The hot flue gas discharged from the outlet of the activation furnace 31 is separated by the cyclone dust collector 320 and enters the preheater through the advanced cyclone 342 to dry the coarse coal gangue in the preheater. The hot flue gas enters the preheater and gradually moves upward through the advanced cyclone 342 until it is discharged from the outlet of the primary cyclone 341, while the coarse coal gangue enters from the inlet of the first cyclone 341 and gradually moves to the last stage cyclone, where it is finally collected and sent to the activation furnace 31.

[0076] The cyclone dust collector 320 can collect the coal gangue products discharged from the outlet of the activation furnace 31. The coal gangue activation products collected by the cyclone dust collector 320 can be used as a substitute for clinker.

[0077] In this embodiment, preferably, the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes a waste heat boiler 8, a denitrification device 7, and a desulfurization device 5. The waste heat boiler 8, the denitrification device 7, and the desulfurization device 5 desulfurize the exhaust gas discharged from the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue.

[0078] Coal gangue contains certain sulfides. After the coal gangue is activated, the relevant sulfides volatilize to form SO2. In order to prevent SO2 from exceeding the standard, desulfurization treatment is also required after denitrification treatment of the waste gas to reduce the SO2 content in the waste gas so that the waste gas can meet the emission standards.

[0079] The volatile components in coal gangue will burn in the primary cyclone separator, resulting in a high temperature at the outlet of the first cyclone separator 341, which is generally greater than 600℃. By adding a waste heat boiler 8, the waste heat from the exhaust gas discharged from the first cyclone separator 341 can be utilized to achieve heat energy recovery.

[0080] Fuel-type nitrogen in coal gangue can generate fuel-type NOx. Therefore, the exhaust gas discharged from the first cyclone 341 will contain a certain amount of nitrogen oxides. In order to prevent nitrogen oxide emissions from exceeding the standard, a denitrification device 7 is added after the waste heat boiler to reduce the nitrogen oxide content in the exhaust gas.

[0081] In this embodiment, preferably, the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes an end bag filter 6 connected to the outlet of the desulfurization unit 5, and the dust filtered by the end bag filter 6 is sent to the bottom of the activation furnace.

[0082] After the exhaust gas is separated by the preheater, it still contains a certain amount of fine powder. This fine powder is collected by the end bag filter 6 and sent to the bottom of the activation furnace.

[0083] This method can reduce the discharge of fine powder. At the same time, because fine coal gangue has a high calorific value, after these fine coal gangue particles are collected and sent to the activation furnace 31, they can be burned in the activation furnace 31 to provide heat for the activation furnace 31.

[0084] If the cement kiln system is used to activate the coal gangue, the external heat source of the activation furnace 31 can be obtained by introducing tertiary air, the temperature of which is approximately 900-1100℃.

[0085] The grinding unit can utilize the raw material grinding system of the cement kiln system, and attention should be paid to washing the grinding mill during grinding. The desulfurization unit 5, denitrification unit 7, and other waste gas treatment equipment can utilize the relevant equipment for kiln tail waste gas treatment in the cement kiln system. The activated product can be preferentially transported to the cement mill system via bulk trucks or pneumatic conveying.

[0086] If the system operates independently, an external heat source can be obtained by adding a hot air furnace or other means. Since the coal gangue in the activation furnace 31 can generate a certain amount of heat through spontaneous combustion, it can basically maintain the internal thermal balance of the system. Therefore, the hot air furnace can be shut down after the internal thermal balance of the system is achieved.

[0087] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0088] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

[0089] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A device for preparing an auxiliary cementitious material from a multi-stage activated coal gangue, characterized by, It includes a hot flue gas system, a grinding unit, and a thermal activation unit. The hot flue gas system draws hot flue gas from the thermal activation unit and sends it into the grinding unit. The thermal activation unit includes an activation furnace (31) for activating coal gangue and a preheater for preheating coal gangue. The grinding unit includes a grinder (21), a cyclone separator (22), and a first bag dust collector (23). After the coal gangue is mechanically activated by the grinder (21), it is separated by the cyclone separator (22) and the first bag dust collector (23). Coarse particles enter the bottom of the activation furnace (31) through the preheater, while fine particles enter the bottom of the activation furnace (31) directly.

2. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 1, characterized in that, The thermal activation unit also includes a sorting device (32), which is connected to the outlet of the activation furnace (31) to screen the activated products. Products with high density are sent into the air inlet pipe (11) at the bottom of the activation furnace (31), and products with low density are sent into the quenching device (33) for cooling.

3. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 2, characterized in that, The preheater includes at least two stages of cyclones, with the primary cyclone (341) comprising multiple cyclones connected in parallel and the advanced cyclone (342) comprising multiple cyclones connected in series.

4. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 2, characterized in that, The quenching equipment (33) includes an equipment body (331) and a cooling fan (333). The equipment body (331) is provided with a cold air inlet (3311), a product inlet (3312) and an outlet (3313). The cooling fan (333) is connected to the cold air inlet (3311), the product inlet (3312) is connected to the sorting equipment (32), and the outlet (3313) is connected to the first filter (4).

5. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 4, characterized in that, The solid obtained from the first filter (4) is sent to the finished product warehouse to replace the clinker, and the gas filtered by the first filter (4) is sent to the activation furnace (31).

6. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 3, characterized in that, A cyclone dust collector (320) is provided between the sorting device (32) and the quenching device (33). The dust collection port of the cyclone dust collector (320) is connected to the quenching device (33), and the outlet of the cyclone dust collector (320) is connected to the inlet of the high-grade cyclone (342).

7. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 1, characterized in that, The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes a waste heat boiler (8), a denitrification device (7), and a desulfurization device (5). The waste heat boiler (8), the denitrification device (7), and the desulfurization device (5) utilize waste heat, perform denitrification treatment, and perform desulfurization treatment on the exhaust gas discharged from the equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue.

8. The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue according to claim 1, characterized in that, The equipment for preparing auxiliary cementitious materials from multi-stage activated coal gangue also includes an end bag filter (6) connected to the outlet of the desulfurization unit (5), and the dust filtered by the end bag filter (6) is sent to the bottom of the activation furnace.

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