Ceramic granule calcination rotary kiln and ceramic granule production method

Abstract

The application discloses a ceramic granule calcination rotary kiln, which comprises a kiln body, a refractory layer is arranged on the inner wall of the kiln body from the kiln head to the kiln tail, the kiln body is sequentially provided with a material blocking check area and a rapid calcination area from the material inlet end to the material outlet section, the material blocking check area is provided with a material inlet side and a material inlet neck, a material blocking boss is arranged in the middle of the material blocking check area, the rapid calcination area is provided with three or more than three arched high parts with curved surface structures along the circumferential direction of the kiln body, and a material outlet neck is arranged at the material outlet section of the rapid calcination area. The application further discloses a method for producing ceramic granules by using the above ceramic granule calcination rotary kiln. The ceramic granule is produced by using the above rotary kiln, so that the internal gas releasing substances of the ceramic granule are orderly released, the ceramic granules with different pore structures are obtained, the liquid phase amount of the surface of the ceramic granule is improved, the porcelainization degree of the surface of the ceramic granule is improved, the water absorption rate is reduced, and the surface strength is improved.

Description

Technical Field

[0001] This invention belongs to the field of rotary kiln and ceramsite calcination technology, and particularly relates to a rotary kiln for ceramsite calcination and a method for producing ceramsite. Background Technology

[0002] Currently, domestically, ceramsite preparation is primarily carried out using plug-in variable-diameter twin-cylinder rotary kilns or single-cylinder long kilns (φ3.5m-65m). These rotary kilns integrate material drying, pelletizing, preheating, calcination, and cooling into a single process. Their advantages lie in their high degree of integration, but their disadvantages include low fuel utilization, high heat loss due to the long kiln body, low output due to low kiln filling rate, large footprint, and a limited variety of ceramsite products. The UK has designed a three-lobed kiln with a high-temperature internal lining made of nickel-cadmium alloy and a three-lobed cross-section, while the external castable refractory uses alumina fiber. This three-lobed rotary kiln is more energy-efficient and environmentally friendly than traditional rotary kilns. However, due to its complex structure and difficult manufacturing process, coupled with uneven thickness of the internal castable refractory, significant thermal stress concentration occurs under high-temperature operation, severely impacting its service life.

[0003] Chinese patent (CN 109539777 A) discloses a rotary kiln, in which the inner wall of the kiln cylinder is lined with a layer of refractory bricks. The refractory brick layer has at least three lifting structures formed by arched protrusions along the axial direction of the cylinder and projecting inwards. These arched protrusions extend beyond the surface of the refractory brick layer on their sides. This patent describes a quasi-trilobal rotary structure constructed along the axial direction within the kiln. The arched lifting structures built with refractory bricks are prone to high wear under material impact, and may even detach, especially when the material is highly viscous or forms rings or snowballs, posing a significant safety risk. Furthermore, the lifting structure has expansion joints, which can easily become blocked when firing large quantities of material, losing their expansion function and further increasing the likelihood of the arched structure detaching. In particular, when installing the material turning cylinder, there is always a corner at the connection between the turning cylinder and the inner wall of the cylinder, which cannot achieve a smooth transition. Therefore, in the actual production process, this part is prone to material accumulation problems and is also prone to crushing the ceramsite, resulting in poor molding quality and high breakage rate.

[0004] Chinese invention (CN103575095B) discloses a waterfall-type rotary kiln, in which at least three material agitation cylinders are installed on the inner wall of the kiln body, extending along the axial direction of the kiln body and arranged in a ring along its cross-section. Each material agitation cylinder is composed of multiple two-section closed cylinders spliced ​​together along the axial direction of the kiln body, with a hollow center and a semi-circular cross-section. This material lifting structure can lift the material to a certain height and then let it fall, improving the heat exchange efficiency of the material. However, when the material agitation cylinders are installed on the inner wall of the rotary kiln body, there is always a corner at the connection between the agitation cylinder and the inner wall of the kiln body, which cannot achieve a smooth transition. Therefore, in the actual production process, this part is prone to material accumulation problems and is also prone to crushing the ceramsite, resulting in poor molding quality and a high breakage rate.

[0005] Chinese invention (CN 113834320 A) discloses a rotary kiln for calcining ceramsite. The inner wall of the kiln cylinder has multiple axially extending grooves evenly distributed around the cylinder, and multiple axially extending protrusions also evenly distributed around the cylinder. Both the protrusions and grooves have arc-shaped cross-sections, and they are alternately arranged with smooth transitions between adjacent protrusions and grooves. The depth of the grooves is much greater than the height of the protrusions, and the arc angle of the groove cross-section is much greater than that of the protrusion cross-section. In this patent, the kiln cylinder is entirely composed of grooves or protrusions, which limits the kiln's rotation speed, resulting in a longer residence time of the ceramsite raw material. This leads to high energy consumption and low thermal efficiency. Furthermore, the lack of buffer material in the grooves results in a high particle breakage rate, especially when the ceramsite raw material first enters the grooves from the kiln tail, where the prolonged residence time further increases the particle breakage rate. The increased dust in the kiln tail flue gas also poses challenges for subsequent processing. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a rotary kiln for calcining ceramsite and a method for producing ceramsite.

[0007] This invention is implemented as follows: a rotary kiln for calcining ceramsite includes a kiln body, the inner wall of which is provided with a refractory layer from the kiln head to the kiln tail. The kiln body is characterized by comprising a material-blocking check zone and a rapid calcining zone sequentially from the feed inlet to the discharge section. A feed inlet narrowing is provided on the feed inlet side of the material-blocking check zone, and a material-blocking protrusion is provided in the middle of the material-blocking check zone. The rapid calcining zone has three or more arched sections with curved surfaces along the circumference of the kiln body; and a discharge narrowing is provided in the discharge section of the rapid calcining zone.

[0008] Preferably, a temperature measuring device is provided on the outer wall of the kiln body that moves horizontally along the kiln body.

[0009] Preferably, the temperature measuring device is an infrared thermometer.

[0010] Preferably, both the inlet and outlet constrictions are provided with inward guide slopes.

[0011] Preferably, the feed inlet end of the arch height section is provided with a guide slope.

[0012] Preferably, the cross-sectional shape of the retaining boss is trapezoidal.

[0013] Preferably, the height of the retaining boss is no greater than 1 / 2 of the height of the arch.

[0014] Preferably, the curve change of the arch height is y=x n A function of , where n is any real number, n > 0.

[0015] The present invention also discloses a method for producing ceramsite, which uses the above-mentioned rotary kiln for ceramsite roasting. An SNCR high-temperature denitrification device is set at the center of the feed end of the rotary kiln. The temperature of the denitrification nozzle of the SNCR high-temperature denitrification device is ≥750℃. The SNCR high-temperature denitrification device is set at the center of the kiln and extends into the kiln tail. Then the rotary kiln is turned on for firing.

[0016] Preferably, the rotational speed of the rotary kiln is 0.5-5 r / min.

[0017] Advantages and technical effects of the present invention: The present invention, by adopting the above technical solution, has the following advantages: 1. By increasing the design of the ceramsite backflow prevention zone, backflow is prevented while the orderly release of gas-generating substances inside the ceramsite is achieved, resulting in ceramsite with different pore structures and bulk densities; at the same time, the breakage rate of ceramsite is reduced.

[0018] 2. The design of the rapid calcination zone improves heat exchange efficiency and filling rate, as well as enhances the erosion resistance of the refractory material. Rapid calcination in this zone increases the amount of liquid phase on the surface of the ceramsite, improves the vitrification degree of the ceramsite surface, reduces water absorption, and increases surface strength.

[0019] Therefore, by optimizing the internal structure design of the rotary kiln, the production of ceramsite is made more efficient and faster, thus improving the productivity of ceramsite. The internal structure design of the ceramsite kiln and its production method of this invention have high application and promotion value, and have broad market prospects in the field of ceramic production. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 yes Figure 1 Sectional view of AA; Figure 3 yes Figure 1 BB section view.

[0021] In the diagram: 1. Kiln body; 101. Material blocking check zone; 111. Material blocking boss; 102. Rapid roasting zone; 103. Feed inlet narrowing; 104. Arch height; 105. Discharge narrowing; 106. Guide slope; 2. Refractory layer; 3. Temperature measuring device. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] Please see Figures 1 to 3 A rotary kiln for calcining ceramsite includes a kiln body 1, with a refractory layer 2 on the inner wall of the kiln body extending from the kiln head (discharge end) to the kiln tail (feed end). The kiln body, from the feed end to the discharge section, consists of a material-blocking check zone 101 and a rapid calcining zone 102. A material-blocking protrusion 111 is provided in the middle of the material-blocking check zone. The cross-sectional shape of the material-blocking protrusion is trapezoidal, and its height is no greater than half the height of the arch section to avoid excessive height. The material-blocking check zone 101 prevents material backflow and provides a sealing function, while also extending the residence time of the material at the kiln tail. This results in a slower heating of the same amount of material per unit time, preventing the ceramsite from directly rushing to the kiln head, thus satisfying the calcination time of the ceramsite blanks and ensuring the quality of the ceramsite. A feed inlet narrowing 103 is provided on the feed inlet side of the material-blocking check zone to reduce ceramsite breakage.

[0024] The rapid firing zone has three or more arched sections 104 with curved surfaces along the circumference of the kiln body. Preferably, the curve of the arched section changes as y=x. n The function is given by , where n is any real number, n > 0; in this embodiment, there are four; rapid calcination zone, the function of the rapid calcination zone is mainly to achieve rapid calcination, rapid heat exchange, and vitrification of the surface of the ceramsite in the thermoplastic state. When entering the rapid calcination zone, facing the high temperature brought by the torch flame, the surface of the ceramsite quickly forms a micro-molten liquid phase, sealing the gas inside the ceramsite. The gas inside will produce a certain uniform expansion, so that the volume of the ceramsite begins to expand instantaneously or slightly. After the ceramsite enters the burner and cools down, the surface of the ceramsite forms a vitrified state, which is beneficial to reduce water absorption and improve surface strength. The interior forms a homogeneous porous structure, reducing the bulk density of the ceramsite; the discharge section of the rapid calcination zone is provided with a discharge constriction 105, which has the function of collecting the ceramsite.

[0025] Preferably, a temperature measuring device 3, which moves horizontally along the kiln body, is installed on the outer wall of the kiln. Preferably, the temperature measuring device is a CS400 rotary kiln thermal imaging system, which continuously monitors the kiln to image each brick in real time, thereby preventing high costs due to downtime and extending equipment uptime. The CS400 rotary kiln thermal imaging system is designed for harsh kiln environments and is an integrated solution. This equipment can monitor the rotary kiln and detect abnormal hot spots, helping your team avoid high costs and unplanned downtime due to kiln damage; it constantly monitors the kiln body, scanning the outer wall and providing real-time feedback on the temperature changes of the entire kiln. If the temperature is higher than the safe temperature, it indicates damage to the refractory material inside the kiln, requiring timely repair; if the temperature is lower, it indicates under-firing, requiring adjustment of the firing temperature.

[0026] Preferably, the feed inlet, the discharge inlet, and the arch height are all provided with inward guide slopes 106 to prevent the ceramsite from breaking during the conveying process, and at the same time to guide the flow.

[0027] This invention also discloses a method for producing ceramsite, which uses the above-mentioned rotary kiln for ceramsite calcination. An SNCR high-temperature denitrification device is set at the center of the feed end of the rotary kiln. The temperature of the denitrification nozzle of the SNCR high-temperature denitrification device is ≥750℃. The SNCR high-temperature denitrification device is set at the center of the kiln and extends into the kiln tail. Then the rotary kiln is turned on for firing. Preferably, the rotation speed of the rotary kiln is 0.5-5 r / min.

[0028] In summary, by optimizing the internal structure design of the rotary kiln, high efficiency and speed in the production of ceramsite have been achieved, thus improving the productivity of ceramsite. The internal structure design of the ceramsite kiln and its production method of this invention have high application and promotion value, and have broad market prospects in the field of ceramic production.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotary kiln for firing ceramsite, comprising a kiln body, wherein the inner wall of the kiln body is provided with a refractory layer from the kiln head to the kiln tail, characterized in that: The kiln body consists of a material-blocking check zone and a rapid roasting zone, extending from the feed inlet to the discharge section. A feed inlet narrowing is located on the feed inlet side of the material-blocking check zone, and a material-blocking protrusion is located in the middle of the material-blocking check zone. The rapid roasting zone has three or more arched sections with curved surfaces along the circumference of the kiln body. A discharge narrowing is located at the discharge section of the rapid roasting zone. A temperature measuring device that moves horizontally along the kiln body is located on the outer wall of the kiln body. The cross-sectional shape of the retaining boss is trapezoidal; The height of the retaining boss is no greater than 1 / 2 of the height of the arch.

2. The rotary kiln for calcining ceramsite according to claim 1, characterized in that: The temperature measuring device is a CS400 rotary kiln thermal imaging system.

3. The rotary kiln for calcining ceramsite according to claim 1, characterized in that: Both the inlet and outlet constrictions are equipped with inward guide slopes.

4. The rotary kiln for calcining ceramsite according to claim 1, characterized in that: The material inlet end of the arch section is provided with a guide slope.

5. The rotary kiln for calcining ceramsite according to claim 1, characterized in that: The curve of the arch height section changes as y=x n A function of , where n is any real number, n > 0.

6. A method for producing ceramsite, characterized in that: The production of ceramsite is carried out using the rotary kiln for calcining ceramsite according to any one of claims 1 to 5. An SNCR high-temperature denitrification device is set at the center of the feed end of the rotary kiln. The temperature of the denitrification nozzle of the SNCR high-temperature denitrification device is ≥750℃. The SNCR high-temperature denitrification device is set at the center of the kiln and extends into the kiln tail. Then the rotary kiln is turned on for firing.

7. The method for producing ceramsite according to claim 6, characterized in that: The rotational speed of the rotary kiln is 0.5-5 r / min.

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