System and method for suspension calcination of kaolin

Abstract

The invention discloses a kaolin suspension calcining system and method.The kaolin suspension calcining system comprises a preheating mechanism, a suspension calcining furnace, a kiln tail cyclone separator and a rotary kiln, the preheating mechanism comprises a first-stage preheater, a second-stage preheater and a bag type dust collector, and the bag type dust collector is communicated with an air outlet of the first-stage preheater through a pipeline; the suspension calcining furnace is respectively communicated with a feed opening of the second-stage preheater and a feed opening of the bag type dust collector, the top of the kiln tail high-temperature cyclone separator is communicated with the waste heat recovery boiler, the waste heat recovery boiler is communicated with gas inlets of the first-stage preheater and the second-stage preheater, a discharge opening of the suspension calcining furnace is communicated with a feed opening of the rotary kiln, and a discharge opening of the bag type dust collector is communicated with a discharge opening of the rotary kiln. The rotary kiln processes the material to form calcined kaolin. The kaolin suspension calcining system provided by the invention has the advantages of good preheating and calcining effects and low production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of kaolin calcination, and particularly relates to a suspension calcination kaolin system and method. Background Art

[0002] Kaolin calcination mostly uses a single rotary kiln or vertical calcination furnace, which has problems such as high energy consumption (thermal efficiency ≤ 40%), uneven calcination resulting in whiteness fluctuations, and residual product impurities. The preheating system is limited by the properties of the material, resulting in insufficient recovery of flue gas waste heat; for the calcination and modification of kaolin, the recrystallization process requires a certain amount of time, and simple suspension calcination cannot achieve a calcination time of dozens of minutes, and the whiteness improvement of the calcined material is limited. In the current kaolin calcination production process, the traditional rotary kiln has high energy consumption, the new suspension calcination process has poor whitening effect, the number of stages of the raw material preheating system is limited, and the production cost is high. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, an embodiment of the present invention provides a suspension calcination kaolin system, which has the advantages of good preheating and calcination effects and low production cost.

[0004] According to the suspension calcination kaolin system of the embodiment of the present invention, the suspension calcination kaolin system includes a preheating mechanism and a suspension calcination furnace. The preheating mechanism includes a primary preheater, a secondary preheater, and a bag filter. The feed inlet of the primary preheater is connected to the air outlet of the secondary preheater through a pipeline. Kaolin raw material powder enters the feed inlet of the primary preheater through a pipeline and exchanges heat with the hot air flow from the secondary preheater. The discharge opening of the primary preheater is connected to the feed inlet of the secondary preheater. The kaolin raw material powder leaves from the discharge opening of the secondary preheater to obtain preheated material. The bag filter is connected to the air outlet of the primary preheater through a pipeline to purify the flue gas. The suspension calcination furnace is respectively connected to the discharge opening of the secondary preheater and the discharge opening of the bag filter to receive the preheated material. The discharge outlet of the suspension calcination furnace is connected to the high-temperature cyclone separator at the kiln tail. The top of the high-temperature cyclone separator at the kiln tail is connected to a waste heat recovery boiler to recover the heat of the flue gas. The waste heat recovery boiler is connected to the gas inlets of the primary preheater and the secondary preheater. The discharge outlet of the high-temperature cyclone separator at the kiln tail is connected to a rotary kiln. The rotary kiln processes the material to form calcined kaolin. The rotary kiln transports the calcined kaolin to the finished product warehouse through a pneumatic conveying device. The rotary kiln transports high-temperature gas to the suspension calcination furnace through a pipeline.

[0005] The advantages brought by the independent claims of the suspension calcination kaolin system according to the embodiments of the present invention. Through the secondary preheater with a high solid-gas ratio and the waste heat recovery boiler for recovering the waste heat of the calcination flue gas, this application solves the problem of frequent blockage of the suspension preheating mechanism, achieves low-temperature flue gas emissions, and significantly reduces energy consumption. At the same time, in the whitening and quality improvement step, the advantages of the rotary kiln in the whitening and quality improvement function are utilized to ensure the quality of the calcined finished product. The material completes decarbonization in the suspension calcination furnace, greatly reducing the heating load required by the rotary kiln, eliminating the need for a large amount of supplementary combustion, and reducing the required air volume at the same time. The expansion of the solid-gas ratio and throughput is realized. Compared with equipment of the same size, the throughput can be increased by 0.5 to 1.5 times.

[0006] In some embodiments, it further includes a tail gas treatment mechanism. The tail gas treatment mechanism is connected to the bag filter to receive the purified flue gas. The tail gas treatment mechanism includes a denitration device and a chimney. The denitration device is connected to the bag filter to denitrate the purified flue gas, and the outlet of the denitration device is connected to the chimney.

[0007] In some embodiments, it further includes a fine powder return furnace fan, and the fine powder return furnace fan supplies air to the pipeline between the discharge end of the bag filter and the suspension calcination furnace.

[0008] In some embodiments, the bottom of the suspension calcination furnace is connected to a first gas supplementary combustion device, and the first gas supplementary combustion device is used to supplement combustion to the suspension calcination furnace.

[0009] In some embodiments, it further includes a cooler, and the cooler is arranged between the rotary kiln and the pneumatic conveying device.

[0010] In some embodiments, it further includes an air supply fan, and the air supply fan is arranged on the discharge side of the cooler.

[0011] In some embodiments, a second gas supplementary combustion device is arranged at the kiln head of the rotary kiln, and the second gas supplementary combustion device is used to supplement combustion to the rotary kiln.

[0012] In some embodiments, it further includes a supplementary combustion air supply fan, and the supplementary combustion air supply fan is connected to the second gas supplementary combustion device to supply air.

[0013] In some embodiments, a second dust collector is arranged on the top of the finished product warehouse, and a packaging device is arranged at the bottom of the finished product warehouse.

[0014] According to the suspension calcination kaolin method of the embodiments of the present invention, the suspension calcination kaolin method includes the following steps:

[0015] Suspension preheating, the kaolin raw material powder is sent into the preheating mechanism for multi-stage preheating.

[0016] Suspension calcination: After preheating, the materials enter the suspension calcination furnace and enter the high-temperature cyclone separator at the kiln tail along with the upward airflow. The materials after calcination are sent into the rotary kiln, and the flue gas of the suspension calcination furnace is sent into the preheating mechanism;

[0017] Whitening: The materials form calcined kaolin after high-temperature treatment in the rotary kiln for a preset time, and the rotary kiln conveys high-temperature gas to the suspension calcination furnace;

[0018] Cooling: The cooler conveys air to the rotary kiln to reduce the temperature of the materials in the rotary kiln. The calcined kaolin continues to be cooled by the cooler to obtain finished powder, and the finished powder is transported to the finished product warehouse. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the suspension calcined kaolin system in the embodiment of the present invention.

[0020] Figure 2 It is a partial enlarged schematic diagram of the preheating mechanism of the suspension calcined kaolin system in the embodiment of the present invention.

[0021] Reference numerals: 1. Preheating mechanism; 11. Primary preheater; 110. Feed inlet; 111. Air outlet; 112. Discharge opening; 12. Secondary preheater; 120. Feed inlet; 121. Air outlet; 122. Discharge opening; 2. Suspension calcination furnace; 21. First gas supplementary combustion device; 22. High-temperature cyclone separator at the kiln tail; 3. Tail gas treatment mechanism; 31. Bag filter; 32. Denitration device; 33. Fine powder return furnace fan; 34. Chimney; 4. Rotary kiln; 41. Supplementary combustion air supply fan; 42. Second gas supplementary combustion device; 5. Cooler; 51. Air supply fan; 52. Finished product conveying fan; 6. Finished product warehouse; 61. Second dust collector; 62. Packaging device; 7. Waste heat recovery boiler. Detailed Description of the Embodiment

[0022] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0023] According to the suspension calcination kaolin system of the embodiments of the present invention, the suspension calcination kaolin system includes a preheating mechanism 1 and a suspension calcination furnace 2. The preheating mechanism 1 includes a primary preheater 11, a secondary preheater 12 and a bag filter 31. The feed inlet 110 of the primary preheater 11 is connected to the air outlet 121 of the secondary preheater 12 through a pipeline. The raw kaolin powder enters the feed inlet 110 of the primary preheater 11 through a pipeline and exchanges heat with the hot air flow from the secondary preheater 12. The discharge outlet 112 of the primary preheater 11 is connected to the feed inlet 120 of the secondary preheater 12. The raw kaolin powder leaves from the discharge outlet 122 of the secondary preheater 12 to obtain preheated material. The bag filter 31 is connected to the air outlet 111 of the primary preheater 11 through a pipeline to purify the flue gas. The suspension calcination furnace 2 is respectively connected to the discharge outlet 122 of the secondary preheater 12 and the discharge outlet of the bag filter 31 to receive the preheated material. The discharge outlet of the suspension calcination furnace 2 is connected to the high-temperature cyclone separator 22 at the kiln tail. The top of the high-temperature cyclone separator 22 at the kiln tail is connected to the waste heat recovery boiler to recover the heat of the flue gas. The waste heat recovery boiler is connected to the gas inlets of the primary preheater 11 and the secondary preheater 12. The discharge outlet of the high-temperature cyclone separator 22 at the kiln tail is connected to the rotary kiln 4. The rotary kiln 4 processes the material to form calcined kaolin. The rotary kiln 4 transports the calcined kaolin to the finished product warehouse 6 through a pneumatic conveying device. The pneumatic conveying device includes a finished product conveying fan 52. The rotary kiln 4 transports high-temperature gas to the suspension calcination furnace 2 through a pipeline. The primary preheater 11 and the secondary preheater 12 can be cyclones. The raw kaolin powder is dispersed and suspended in the hot air flow under the action of the hot air flow in the secondary preheater 12. In the primary preheater 11, the hot air flow exchanges heat with the raw kaolin powder. The heat transfer between the gas-solid phases enables the heat of the hot air flow to be absorbed by the raw kaolin powder, thereby initially increasing the temperature of the raw kaolin powder. After the temperature rise, the raw kaolin powder enters the secondary preheater 12 for further temperature rise. In the secondary preheater 12, the raw kaolin exchanges heat with the hot air flow to further increase the temperature. The hot air flow in the secondary preheater 12 comes from the suspension calcination furnace 2 and the rotary kiln 4. The hot air flow in the primary preheater 11 comes from the secondary preheater 12. By preheating the raw kaolin powder by making full use of the waste heat of the flue gas through two-stage preheating, the heat consumption of the suspension calcination furnace 2 can be reduced, the energy utilization rate of the system can be improved, and the raw kaolin powder can reach a more appropriate temperature range before entering the suspension calcination furnace 2, which is beneficial to the subsequent calcination reaction to proceed more evenly and fully. The bag filter 31 purifies the flue gas discharged from the primary preheater 11, reduces environmental pollution, and the collected dust can be recycled to reduce material loss and improve material utilization rate.

[0024] In some embodiments, a tail gas treatment mechanism 3 is further included. The tail gas treatment mechanism 3 is connected to the bag filter 31 to receive the purified flue gas. The tail gas treatment mechanism 3 includes a denitration device 32 and a chimney 34. The denitration device 32 is connected to the bag filter 31 to denitrate the purified flue gas, and the outlet of the denitration device 32 is connected to the chimney 34.

[0025] Specifically, the tail gas treatment mechanism 3 is connected to the bag filter 31 to receive the flue gas purified by the bag filter 31. The denitration device 32 is connected to the bag filter 31 to perform denitration treatment on the purified flue gas. The denitration device 32 can generally adopt technologies such as selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR). The denitration reducing agent (such as ammonia) reacts chemically with nitrogen oxides (NOx) in the flue gas to generate nitrogen and water, thereby effectively reducing the concentration of NOx in the flue gas. The outlet of the denitration device 32 is connected to the chimney 34, and the flue gas after denitration treatment is discharged into the atmosphere through the chimney 34, ensuring that the discharged flue gas meets environmental protection standards and reducing environmental pollution. The chimney 34 is used to discharge the flue gas after denitration treatment to ensure that the flue gas can be fully diffused at high altitude and reduce the impact on ground air quality. The dust collected by the bag filter 31 can be returned to the system for reuse, reducing material waste, improving resource utilization rate, and also reducing production costs. The flue gas purified by the bag filter 31 has a low dust content, and after entering the tail gas treatment mechanism 3, it causes less wear on the equipment. At the same time, the use of the denitration device 32 also reduces the corrosion of corrosive gases in the flue gas to the equipment, extends the service life of the equipment, and reduces equipment maintenance costs.

[0026] In some embodiments, a fine powder return blower 33 is further included. The fine powder return blower 33 blows air into the pipeline between the discharge end of the bag filter 31 and the suspension calciner 2.

[0027] Specifically, the fine powder return blower blowing air into the pipeline between the discharge end of the bag filter 31 and the suspension calciner 2 can smoothly transport the fine powder material collected by the bag filter 31 back to the suspension calciner 2 for re-calcination, making full use of the potential value of these fine powders, improving the material utilization rate of the entire system, reducing material waste, and reducing production costs. And the air flow sent by the fine powder return blower 33 can not only transport the fine powder, but also play a certain disturbing role in the suspension calciner 2, enabling the fine powder to be fully mixed with the high-temperature gas and materials in the furnace, further optimizing the calcination process, and improving the calcination efficiency and product quality. The air flow of the fine powder return blower 33 can effectively prevent the fine powder from accumulating and blocking in the pipeline, ensuring the continuity and stability of material transportation. By sending the fine powder back to the suspension calciner 2, the fine powder return blower 33 reduces the escape of fine powder in the system and reduces the dust concentration in the working environment.

[0028] In some embodiments, the bottom of the suspension calciner 2 is connected to the first gas supplementary combustion device 21, and the first gas supplementary combustion device 21 is used to supplement combustion to the suspension calciner 2.

[0029] Specifically, by supplementing combustion to the suspension calciner 2, the first gas supplementary combustion device 21 provides additional heat to ensure that the temperature inside the furnace reaches or is maintained within the ideal calcination temperature range. During the operation of the suspension calciner 2, the airflow and the kaolin raw material powder carry away heat, and additional heat is required to maintain or increase the temperature inside the furnace. During the production process, the temperature of the suspension calciner 2 may be affected by various factors, such as fluctuations in the calorific value of the raw materials and changes in the feed rate. The first gas supplementary combustion device 21 adjusts according to the need and timely supplements heat, so as to stabilize the temperature inside the furnace and ensure the stability of the calcination process. The first gas supplementary combustion device 21 can be a natural gas supplementary combustion device.

[0030] The stable heat provided by the supplementary combustion device can make the temperature distribution inside the suspension calciner 2 more uniform, avoid problems such as local overheating or insufficient calcination, thereby improving the quality of calcined kaolin and making it have a more uniform particle size distribution and better physical properties. The supplementary combustion device can adjust the heat according to the actual needs of the suspension calciner 2, avoid overheating or heat waste, and thus optimize the energy utilization efficiency.

[0031] In some embodiments, it further includes a cooler, and the cooler is arranged between the rotary kiln 4 and the pneumatic conveying device.

[0032] Specifically, the cooler is a single-cylinder cooler. The single-cylinder cooler drives the material to conduct sufficient heat exchange with the cold air through the rotation of the cylinder body, and can cool the high-temperature material coming out of the rotary kiln 4 to below 200°C. It can quickly reduce the material temperature and prevent the material from undergoing excessive reactions or sintering at high temperatures, thereby maintaining its good physical properties. While cooling the material, the single-cylinder cooler can recycle the heat carried by the material. The cooled hot air can be sent into the rotary kiln 4 as secondary circulating air to improve the thermal efficiency of the kiln. This waste heat recovery method not only reduces the system's demand for fresh energy but also reduces energy consumption.

[0033] In some embodiments, it further includes an air supply fan 51, and the air supply fan 51 is arranged on the discharge side of the cooler.

[0034] Specifically, the air supply fan 51 arranged on the discharge side of the cooler makes the air flow countercurrently to exchange heat with the material inside the cooler, further reducing the temperature of the material to make it reach the temperature range suitable for subsequent processing. The air supply fan 51 delivering cold air to the cooler can accelerate cooling and improve the cooling efficiency.

[0035] In some embodiments, a second gas supplementary combustion device 42 is provided at the kiln head of the rotary kiln 4, and the second gas supplementary combustion device 42 is used to supplement combustion to the rotary kiln 4.

[0036] Specifically, the second gas supplementary combustion device 42 may be a natural gas supplementary combustion device. By supplementing combustion to the rotary kiln 4, the second gas supplementary combustion device 42 provides additional heat to ensure that the temperature inside the kiln reaches or is maintained within the ideal calcination temperature range. The temperature of the rotary kiln 4 may be affected by various factors, such as fluctuations in the calorific value of the raw materials, changes in the feed rate, and the entry and exit of materials and flue gas. The second gas supplementary combustion device 42 can be adjusted as needed to timely supplement heat, thereby stabilizing the temperature inside the kiln and ensuring the stability of the calcination process. The stable heat provided by the second supplementary combustion device can make the temperature distribution inside the rotary kiln 4 more uniform, avoiding problems such as local overheating or insufficient calcination, thereby improving the quality of calcined kaolin, making it have a more uniform particle size distribution and better physical properties. The stable calcination temperature and sufficient calcination reaction contribute to improving the whiteness and purity of calcined kaolin, meeting the requirements of higher-quality products.

[0037] In some embodiments, a supplementary combustion air blower 41 is further included, and the supplementary combustion air blower 41 is connected to the second gas supplementary combustion device 42 to supply air.

[0038] Specifically, the supplementary combustion air blower 41 is connected to the second gas supplementary combustion device 42 to provide sufficient combustion-supporting air for the supplementary combustion device. Combustion-supporting air is an essential part of the gas combustion process, which can ensure full combustion of the gas and improve the combustion efficiency. The combustion-supporting air provided by the supplementary combustion air blower 41 can adjust the ratio of gas to air, optimize the combustion process, reduce incomplete combustion phenomena, and reduce pollutant emissions. The supplementary combustion air blower 41 can stabilize the combustion temperature by adjusting the air volume according to the temperature change inside the rotary kiln 4. When the temperature is too high, the air volume can be increased to lower the temperature; when the temperature is too low, the air volume can be reduced to raise the temperature. The supplementary combustion air blower 41 can adjust the air volume according to the actual needs of the rotary kiln 4, avoiding excessive air supply or insufficient air supply, thereby optimizing the energy utilization efficiency.

[0039] In some embodiments, a second dust collector 61 is provided at the top of the finished product warehouse 6, and a packaging device 62 is provided at the bottom of the finished product warehouse 6.

[0040] Specifically, the second dust collector 61 is used to purify the dust-containing gas in the finished product warehouse 6, reduce the dust generated during the storage and transportation of materials, and avoid direct emission into the atmosphere to cause environmental pollution. Thus, the equipment in the finished product warehouse 6 is protected from dust erosion, and the service life of the equipment is extended. At the same time, the diffusion of dust in the working environment is reduced, protecting the health of the staff. The packaging device 62 is used to package the calcined kaolin finished product for transportation and sales. The packaging device 62 can achieve automated operation, improve the packaging efficiency, reduce the errors and cumbersome processes of manual operation, reduce the labor intensity, and improve the work efficiency.

[0041] According to the method for suspension calcination of kaolin in an embodiment of the present invention, the method for suspension calcination of kaolin includes the following steps:

[0042] Suspension preheating: The raw kaolin powder is fed into the preheating mechanism 1 for multi-stage preheating.

[0043] Suspension calcination: After preheating, the material enters the suspension calcination furnace 2 and enters the high-temperature cyclone separator 22 at the kiln tail along with the upward air flow. After calcination is completed, the material is fed into the rotary kiln 4, and the flue gas of the suspension calcination furnace 2 is fed into the preheating mechanism 1.

[0044] Whitening: The material undergoes high-temperature treatment in the rotary kiln 4 for a preset time to form calcined kaolin, and the rotary kiln 4 conveys high-temperature gas to the suspension calcination furnace 2.

[0045] Cooling: The cooler conveys air to the rotary kiln 4 to reduce the temperature of the material in the rotary kiln 4. The calcined kaolin continues to be cooled by the cooler to obtain the finished powder, and the finished powder is transported to the finished product warehouse 6.

[0046] In the suspension preheating step, the raw kaolin powder is lifted to the top of the first preheater by a hoist. The raw kaolin powder enters the first preheater and is suspended under the action of the hot air flow of the second preheater. After heat exchange in the first preheater, the raw kaolin powder enters the second preheater from the cone of the first cyclone through a weight flap valve. The waste heat recovery boiler sends 700°C flue gas into the second preheater to perform secondary preheating on the raw kaolin powder to obtain the preheated material. The first preheater conveys 200°C hot air flow to the bag filter 31. The material collected by the bag filter 31 is discharged with air lock and discharged into the suspension calcination furnace 2 together with the material of the second cyclone. The purified flue gas can be sent to the grinding system for drying raw materials. When the mill in the grinding system is not operating, the purified flue gas is directly discharged from the chimney 34.

[0047] The preheated material is fed into the lower part of the suspension calciner 2 and calcined inside. The material in the furnace enters the high-temperature cyclone separator 22 at the kiln tail with the upward airflow for separation and collection. The collected material is discharged into the rotary kiln 4 through the airtight discharging at the cone part, and slowly moves towards the kiln head by means of the slope and rotation of the rotary kiln 4. After the material undergoes high-temperature heat preservation for a certain residence time in the kiln, finally, high-quality calcined kaolin meeting the requirements is formed. The heat required for calcination in the calciner is provided by the combustion of gas sprayed by the natural gas burner arranged at the bottom of the suspension calciner 2. The flue gas generated by the calcination in the calciner is separated by the high-temperature cyclone separator 22 at the kiln tail and discharged from the top and enters the second preheater to provide heat for preheating the raw material. The separated finished product enters the rotary kiln 4 for quality improvement and whitening. After passing through the rotary kiln 4, it enters the single-cylinder cooler, and the cooled finished powder is transported to the finished product warehouse 6 by the pneumatic conveying system for storage.

[0048] The clean air for cooling the cooler is stably provided by the configured fan. This path of gas is heated through heat exchange and then sent to the rotary kiln 4 to provide heat source for maintaining the heat preservation inside the rotary kiln 4. At the same time, the second gas supplementary combustion device 42 at the kiln head of the rotary kiln 4 serves as the backup heat supplement during heat preservation. This path of air is sent to the lower part of the suspension calciner 2 as the combustion air after passing through the rotary kiln 4, recovering the heat of the calcined finished product.

[0049] Example 1: A 300,000-ton / year calcined kaolin production line designed according to the above method. The raw material uses high-aluminum coal gangue with an internal water content of 15%. After raw material crushing and batching, raw material with a calorific value of about 400 kcal is obtained, pulverized to 45 μm, sent to the raw material warehouse, and transported to the suspension preheating system by the pneumatic conveying equipment. After suspension preheating in the second cyclone, the raw kaolin powder is preheated to 350 °C. The raw kaolin powder enters the bottom of the suspension calciner 2 and is heated by the high-temperature air of about 800 °C from the rotary kiln 4, ignited, and flows upward in a suspended state with the air to complete decarbonization. The first burner at the bottom of the suspension calciner 2 provides the remaining heat to keep the calcination temperature maintained at 1300 °C. The material completes decarbonization and modification in the calciner and leaves from the top of the suspension calciner 2 and enters the high-temperature cyclone separator 22 at the kiln tail to separate the calcined flue gas and the material. The flue gas enters the preheating system, and the material enters the rotary kiln 4 for heat preservation. In the rotary kiln 4, it contacts countercurrently with the air of about 750 °C from the single-cylinder cooler. The material gradually decreases to 1000 °C, and the air is further heated to 850 °C. The 850 °C air enters the suspension calciner 2, and the material enters the single-cylinder cooler and is cooled to 150 °C and transported to the finished product warehouse 6 by pneumatic conveying. Compared with the traditional rotary kiln process, the comprehensive energy consumption is reduced by more than 40%. The whiteness of the kaolin product is stable ≥ 90%. After secondary calcination for quality improvement, the product uniformity is significantly improved, and the overall calcination process time is shortened to about 1 hour.

[0050] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0051] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0052] In the present invention, unless otherwise clearly specified and defined, the terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection or communication with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0054] In the present invention, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0055] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A suspension calcined kaolin system, characterized in that: include: A preheating mechanism, the preheating mechanism comprises a primary preheater, a secondary preheater and a bag dust collector, the feed port of the primary preheater is connected with the air outlet of the secondary preheater through a pipeline, the kaolin raw material powder enters the feed port of the primary preheater through a pipeline and exchanges heat with the hot air flow from the secondary preheater, the discharge port of the primary preheater is connected with the feed port of the secondary preheater, the kaolin raw material powder leaves the discharge port of the secondary preheater to obtain the preheated material, and the bag dust collector is connected with the air outlet of the primary preheater through a pipeline to purify the flue gas; A suspension calcining furnace, wherein the suspension calcining furnace is respectively connected to the discharge port of the secondary preheater and the discharge port of the bag dust collector to receive the preheated material, the discharge port of the suspension calcining furnace is connected to the high-temperature cyclone separator at the end of the kiln, the top of the high-temperature cyclone separator at the end of the kiln is connected to a waste heat recovery boiler to recover the heat of flue gas, the waste heat recovery boiler is connected to the gas inlet of the primary preheater and the secondary preheater, the discharge port of the high-temperature cyclone separator at the end of the kiln is connected to a rotary kiln, the rotary kiln processes the material to form calcined kaolin, the rotary kiln transports the calcined kaolin to the finished product warehouse through a pneumatic conveying device, and the rotary kiln transports high-temperature gas to the suspension calcining furnace through a pipeline.

2. The suspension calcined kaolin system according to claim 1, characterized in that: It also includes an exhaust gas treatment mechanism, which is connected to the bag dust collector to receive the purified flue gas. The exhaust gas treatment mechanism includes a denitrification device and a chimney. The denitrification device is connected to the bag dust collector to denitrify the purified flue gas, and the outlet of the denitrification device is connected to the chimney.

3. The suspension calcined kaolin system according to claim 2, characterized in that: It also includes a fine powder return fan, which supplies air to the pipeline between the discharge end of the bag filter and the suspension calcining furnace.

4. The suspension calcined kaolin system according to claim 1, characterized in that: The bottom of the suspension calcining furnace is connected to a first gas supplementary combustion device, and the first gas supplementary combustion device is used for supplementary combustion to the suspension calcining furnace.

5. The suspension calcined kaolin system according to claim 1, characterized in that: The invention also comprises a cooler, which is arranged between the rotary kiln and the pneumatic conveying device.

6. The suspension calcined kaolin system according to claim 5, characterized in that: It also includes an air supply fan, which is arranged on the discharge side of the cooler.

7. The suspension calcined kaolin system according to claim 1, characterized in that: A second gas supplementary combustion device is arranged at the kiln head of the rotary kiln, and the second gas supplementary combustion device is used for supplementary combustion to the rotary kiln.

8. The suspension calcined kaolin system according to claim 7, characterized in that: It also includes a supplementary combustion air supply fan, which is connected to the second gas supplementary combustion device for supplying air.

9. The suspension calcined kaolin system according to claim 1, characterized in that: A second dust collector is arranged on the top of the finished product warehouse, and a sub-packaging device is arranged on the bottom of the finished product warehouse.

10. A method for suspension calcining kaolin, using the suspension calcining kaolin system according to claims 1 to 9, characterized in that: The following steps are involved: Suspension preheating, kaolin raw material powder is sent into the preheating mechanism for multi-stage preheating, Suspension calcination: after preheating, the material enters the suspension calcination furnace and follows the airflow from bottom to top into the high-temperature cyclone separator at the end of the kiln. After calcination, the material is sent to the rotary kiln, and the flue gas from the suspension calcination furnace is sent to the preheating mechanism. Whitening, the material is subjected to high temperature treatment for a preset time in the rotary kiln to form calcined kaolin, and the rotary kiln delivers high temperature gas to the suspension calcining furnace; Cooling: a cooler delivers air to the rotary kiln to lower the temperature of the material in the rotary kiln; the calcined kaolin is further cooled by the cooler to obtain a finished powder; and the finished powder is delivered to a finished product warehouse.

Images