Electric heating rotary kiln

Abstract

According to the electric heating rotary kiln, different working conditions are divided according to the detection temperatures of a first temperature detector and a second temperature detector, the heating temperatures of a main heating coil, an auxiliary heating coil and a heat preservation heating coil and the air volume of an air supply device are adaptively adjusted, and the purposes that the initial supply amount of high-temperature gas is sufficient; the technical effects of reducing heating wire loss, reducing the probability of high-temperature fusing caused by temperature rise, reducing system energy consumption, preventing a large amount of gas with the temperature lower than 1050 DEG C from entering the rotary kiln to affect spodumene transformation, ensuring production continuity and the like are achieved, the efficient, energy-saving and adjustable electric heating rotary kiln is built, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of spodumene roasting, specifically to an electrically heated rotary kiln. Background Technology

[0002] In industrial production, spodumene concentrate is mainly used as the raw material for lithium extraction by the sulfuric acid process. Spodumene undergoes a transformation roasting process to transform the high-density, chemically stable α-spodumene into the low-density, loosely structured β-spodumene that can react with acids and bases. Through acid roasting, the lithium element in spodumene is converted from lithium oxide to lithium sulfate.

[0003] Currently, spodumene roasting primarily uses natural gas or coal gas as fuel. The fuel combustion heats the air inside a rotary kiln, calcining the spodumene to achieve crystal transformation or reaction with concentrated sulfuric acid. However, this production method also has many problems. First, fuel combustion consumes non-renewable resources and produces large amounts of carbon dioxide and other gases, negatively impacting the environment. Second, complete combustion of the fuel within the kiln is difficult to guarantee, resulting in unstable temperatures in the roasting zone, leading to poor spodumene transformation and acidification, ultimately affecting the lithium extraction efficiency of the entire production line.

[0004] In addition, existing electrically heated rotary kilns mainly use the thermal effect of electric current or the principle of electromagnetic induction to heat the air inside the kiln at high temperatures. The lithium spodumene material inside the kiln is roasted by high-temperature air. Although carbon emissions are reduced to some extent, there are still problems such as high energy consumption of the heating method and unsatisfactory energy consumption regulation effect, the rotary kiln cylinder being subjected to long-term direct high-temperature heating during rotation, which cannot guarantee the strength of the cylinder, and high losses of heating coils. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, the present invention provides an electrically heated rotary kiln.

[0006] The specific technical solution is as follows: it includes a rotary kiln body, an electric heating generator, a main heating coil, an auxiliary heating coil, a heat preservation heating coil, a first thermometer, a second thermometer, an air supply device, and an electrical control device.

[0007] The electric heating generator includes a high-temperature gas output zone, a generator body, and a heat exchange gas inlet zone; the high-temperature gas output zone extends into the rotary kiln; the generator body is provided with two temperature measuring holes, the first temperature measuring hole is located at half the axial length of the generator body, and the second temperature measuring hole is located at one-quarter of the axial length of the generator body near the rotary kiln, and the first thermometer and the second thermometer are respectively inserted into the first temperature measuring hole and the second temperature measuring hole to measure the gas temperature inside the generator; the heat exchange gas inlet zone is connected to the air outlet of the air supply device.

[0008] The electrical control device includes a main heating controller, an auxiliary heating controller, a heat preservation heating controller, a main controller, and an electrical control cabinet. The main heating controller is connected to the main heating coil, the auxiliary heating controller is connected to the auxiliary heating coil, the first thermometer, and the air supply device, and the heat preservation heating controller is connected to the heat preservation heating coil, the second thermometer, and the air supply device. The main heating controller, the auxiliary heating controller, and the heat preservation heating controller are connected to the electrical control cabinet through the main controller. The electrical control cabinet provides electrical circuit protection for the entire electrically heated rotary kiln.

[0009] The main heating coil, auxiliary heating coil, and heat preservation heating coil are fixedly installed on the inner wall of the generator body and arranged sequentially along the gas flow direction. The generator body is correspondingly set as the main heating zone, auxiliary heating zone, and heat preservation heating zone.

[0010] At the start of the roasting process, the electrical control device simultaneously activates the main heating coil, auxiliary heating coil, and heat preservation heating coil, setting the heating temperature to 400℃ to heat the gas inside the generator body. When the first and second thermometers show a temperature of 350℃, the main heating coil temperature is adjusted to 350℃, and the auxiliary heating coil and heat preservation heating coil temperature is adjusted to 300℃. The air supply device is then activated, which blows gas into the generator body through the heat exchange gas inlet zone. The newly introduced gas drives the already heated 350℃ high-temperature gas inside the generator body into the rotary kiln body through the high-temperature gas outlet zone, roasting the spodumene inside the kiln.

[0011] The electric heating rotary kiln adjusts its heating supply according to the operating conditions via an electronic control device.

[0012] Furthermore, the turns ratio of the main heating coil, auxiliary heating coil, and heat preservation heating coil is 4:2:1. By rationally configuring the turns ratio of the heating coils, both the supply of high-temperature gas and the energy consumption of the system are guaranteed.

[0013] Furthermore, an insulation layer is installed on the outside of the electric heating generator to keep the internal gas warm and reduce heat loss.

[0014] In addition, to prevent a decrease in heating efficiency, when the first thermometer shows a temperature below 350℃, indicating that the gas temperature heated from the main heating zone is insufficient for spodumene roasting, the auxiliary heating controller adjusts the auxiliary heating coil temperature to 350℃ to further heat the gas entering the auxiliary heating zone, ensuring that the gas temperature entering the rotary kiln from the electric heater meets the requirements for spodumene roasting. Simultaneously, the airflow from the air supply device is reduced to increase the gas residence time in the main heating zone without increasing the main heating coil temperature, thus ensuring the heating effect of the main heating zone. Through continuous heating by the main and auxiliary heating coils, when the first thermometer shows a temperature above 350℃, the auxiliary heating controller adjusts the auxiliary heating coil temperature to 300℃ and increases the airflow from the air supply device.

[0015] When the second thermometer shows a temperature below 350℃, it indicates that the gas temperature entering the rotary kiln does not meet the requirements for spodumene conversion roasting. The insulation heating controller adjusts the insulation heating coil temperature to 350℃ to further heat the gas entering the insulation heating zone and increase its temperature; it also shuts off the air supply device to prevent a large amount of gas below 350℃ from entering the rotary kiln. Through continuous heating by the main heating coil and the insulation heating coil, when the second thermometer shows a temperature above 350℃, the insulation heating controller adjusts the insulation heating coil temperature to 300℃ and turns on the air supply device.

[0016] When the main heating coil suddenly fails due to prolonged high-temperature heating, the circuit breaker in the electrical control cabinet disconnects the main heating coil circuit. The main controller instructs the auxiliary heating controller and the heat preservation heating controller to adjust the heating temperature of the auxiliary heating coil and the heat preservation heating coil to 400℃, which serves as a temporary "main heating coil". The air volume of the air supply device is reduced. The main heating coil will be repaired or replaced when the production line is scheduled to stop or be repaired, thus ensuring the continuity of production.

[0017] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0018] 1. The electrically heated rotary kiln disclosed in this utility model first sets a high temperature through the main heating coil, auxiliary heating coil, and heat preservation heating coil, while simultaneously heating the air inside the main body of the generator to ensure a sufficient initial supply of high-temperature gas required for the rotary kiln's calcination. Once the temperature meets the calcination requirements, the heating temperatures of the auxiliary heating coil and the heat preservation heating coil are actively reduced. Compared to existing electrically heated kilns, this method ensures that the calcination requirements are met while reducing the wear and tear on the coils themselves due to continuous high-temperature heating, extending their service life, and reducing system energy consumption.

[0019] 2. The electrically heated rotary kiln disclosed in this utility model adaptively adjusts the heating temperatures of the main heating coil, auxiliary heating coil, and heat preservation heating coil, as well as the air volume of the air supply device, based on the temperatures detected by the first and second thermometers. Compared to continuous high-temperature constant-temperature heating, the heating method of this utility model ensures a sufficient initial supply of high-temperature gas while reducing system energy consumption. It also reduces the wear and tear on the heating coils caused by continuous high temperatures during subsequent production and lowers the probability of high-temperature melting of the main heating coil due to temperature increases. Furthermore, it avoids the large-scale entry of gases below the reaction temperature into the rotary kiln, which could affect spodumene roasting, thus ensuring continuous production. This results in a highly efficient, energy-saving, and adjustable electrically heated rotary kiln, reducing production costs and improving production efficiency. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the electrically heated rotary kiln of this utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the electrical control device of this utility model;

[0022] Figure 3 This is a schematic diagram showing the circuit connection relationship between the various components of the electronic control device of this utility model;

[0023] Figure 4 This is a schematic diagram of the main body of the generator of this utility model;

[0024] Figure 5 This is a schematic cross-sectional view of the generator body of this utility model.

[0025] Wherein: 1-Rotary kiln body; 2-Electric heating generator; 21-High temperature gas output zone; 22-Generator body; 221-First temperature measuring hole; 222-Second temperature measuring hole; 23-Heat exchange gas inlet zone; 3-Electrical control device; 31-Insulation heating controller; 32-Second thermometer; 33-Auxiliary heating controller; 34-First thermometer; 35-Main heating controller; 36-General controller; 37-Electrical control cabinet; 4-Air supply device; 5-Fixed bracket; 61-Main heating coil; 62-Auxiliary heating coil; 63-Insulation heating coil; 7-Insulation layer. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be further described below with reference to the accompanying drawings. The following description presents a preferred embodiment of several possible embodiments of this utility model, intended to provide a basic understanding of the utility model, but is not intended to identify the key or decisive elements of this utility model or to limit the scope of protection sought.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the implementation of the present invention is not limited thereto.

[0029] See appendix Figure 1-4This embodiment provides an electrically heated rotary kiln, including a rotary kiln body 1, an electric heater 2, a main heating coil 61, an auxiliary heating coil 62, a heat preservation heating coil 63, a first thermometer 34, a second thermometer 32, an air supply device 4, and an electrical control device 3.

[0030] The electric heating generator 2 includes a high-temperature gas output zone 21, a generator body 22, and a heat exchange gas inlet zone 23; the high-temperature gas output zone 21 extends into the rotary kiln body 1; the generator body 22 is provided with two temperature measuring holes, the first temperature measuring hole 221 is located at half the axial length of the generator body 22, and the second temperature measuring hole 222 is located at one-quarter of the axial length of the generator body 22 near the rotary kiln body 1; the first thermometer 34 and the second thermometer 32 are respectively inserted into the first temperature measuring hole 221 and the second temperature measuring hole 222 to measure the gas temperature inside the generator body 22; the heat exchange gas inlet zone 23 is connected to the air outlet of the air supply device 4.

[0031] The electrical control device 3 includes a main heating controller 35, an auxiliary heating controller 33, a heat preservation heating controller 31, a main controller 36, and an electrical control cabinet 37. The main heating controller 35 is connected to the main heating coil 61, the auxiliary heating controller 33 is connected to the auxiliary heating coil 62, the first thermometer 34, and the air supply device 4, and the heat preservation heating controller 31 is connected to the heat preservation heating coil 63, the second thermometer 32, and the air supply device 4. The main heating controller 35, the auxiliary heating controller 33, and the heat preservation heating controller 31 are connected to the electrical control cabinet 37 through the main controller 36. The electrical control cabinet 37 provides circuit protection for the entire electrically heated rotary kiln.

[0032] The main heating coil 61, auxiliary heating coil 62 and heat preservation heating coil 63 are fixedly installed on the inner wall of the generator body 22 and arranged sequentially along the gas flow direction. The generator body 22 is correspondingly set as the main heating zone, auxiliary heating zone and heat preservation heating zone.

[0033] At the start of the roasting process, the electrical control device 3 first simultaneously activates the main heating coil 61, the auxiliary heating coil 62, and the heat preservation heating coil 63, setting the heating temperature to 400℃. The gas inside the generator body 22 is heated using the current heating effect. When the first thermometer 34 and the second thermometer 32 show a temperature of 350℃, the heating temperature of the main heating coil 61 is adjusted to 350℃, and the heating temperatures of the auxiliary heating coil 62 and the heat preservation heating coil 63 are adjusted to 300℃. The air supply device 4 is then activated. The air supply device 4 blows gas into the generator body 22 through the hot gas inlet zone 23. The newly entered gas drives the high-temperature gas already heated to 350℃ inside the generator body 22 into the rotary kiln body 1 along the high-temperature gas outlet zone, roasting the spodumene inside the kiln.

[0034] The electric heating conversion roasting system adjusts the heating supply according to the operating conditions through the electric control device 3.

[0035] More specifically, the turns ratio of the main heating coil 61, the auxiliary heating coil 62, and the heat preservation heating coil 63 is 4:2:1. By rationally configuring the turns ratio of the heating coils, both the supply of high-temperature gas and the energy consumption of the system are guaranteed.

[0036] More specifically, see Appendix Figure 5 The electric heating generator 2 is equipped with an insulation layer 7 to reduce the loss of heat from the internal gas.

[0037] In addition, to prevent a decrease in heating efficiency, when the first thermometer 34 displays a temperature below 350°C, it indicates that the gas temperature heated from the main heating zone cannot meet the requirements for spodumene roasting. The auxiliary heating controller 33 adjusts the heating temperature of the auxiliary heating coil 62 to 350°C to further heat the gas entering the auxiliary heating zone, ensuring that the gas temperature entering the rotary kiln body 1 from the electric heater 2 meets the requirements for spodumene roasting. At the same time, the air volume of the air supply device 4 is reduced, and the air volume is denoted as q2m. 3 / min, without increasing the heating temperature of the main heating coil, increases the residence time of the gas in the main heating zone to ensure the heating effect of the main heating zone. Through continuous heating by the main heating coil 61 and the auxiliary heating coil 62, when the first thermometer 34 displays a detected temperature greater than 350℃, the auxiliary heating controller 33 adjusts the heating temperature of the auxiliary heating coil 62 to 300℃ and increases the air volume of the air supply device 4, which is recorded as q3m. 3 / min.

[0038] Furthermore, the relationship between the air volume and its magnitude is q1m 3 / min>q3m 3 / min>q2m 3 / min.

[0039] When the second thermometer 32 displays a temperature below 350℃, it indicates that the gas temperature about to enter the rotary kiln body 1 does not meet the requirements for spodumene roasting. The insulation heating controller 31 adjusts the heating temperature of the insulation heating coil 63 to 350℃ to further heat the gas entering the insulation heating zone and increase its temperature; and shuts off the air supply device 4 to prevent a large amount of gas with a temperature below 350℃ from entering the rotary kiln body 1. Through continuous heating by the main heating coil 61 and the insulation heating coil 63, when the second thermometer 32 displays a temperature above 350℃, the insulation heating controller 31 adjusts the heating temperature of the insulation heating coil to 300℃ and turns on the air supply device 4, setting the airflow to q4m. 3 / min.

[0040] Furthermore, the relationship between air volume and its magnitude is q1m 3 / min>q4m 3 / min.

[0041] When the main heating coil suddenly malfunctions due to prolonged high-temperature heating, the circuit breaker in the electrical control cabinet 37 disconnects the main heating coil 61 circuit. The main controller in the electrical control cabinet 37 then instructs the auxiliary heating controller 33 and the insulation heating controller 31 to adjust the heating temperature of the auxiliary heating coil 62 and the insulation heating coil 61 to 400℃, acting as a temporary "main heating coil." The airflow of the air supply device 4 is reduced, and the airflow is set to q5m³. 3 The main heating coil 61 will be repaired or replaced only after the production line has scheduled a shutdown for maintenance, ensuring continuous production.

[0042] Furthermore, the relationship between air volume and its magnitude is q1m 3 / min>q5m 3 / min.

[0043] In this document, the directional terms such as front, back, top, and bottom are defined based on the position of the components in the accompanying drawings and their relative positions to each other, solely for the purpose of clarity and convenience in expressing the technical solution. It should be understood that these are relative concepts and can vary depending on different methods of use and placement; the use of these directional terms should not limit the scope of protection claimed in this application.

[0044] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An electrically heated rotary kiln, characterized in that: It includes a rotary kiln body (1), an electric heating generator (2), a main heating coil (61), an auxiliary heating coil (62), a heat preservation heating coil (63), a first thermometer (34), a second thermometer (32), an air supply device (4), and an electrical control device (3); The electric heating generator (2) includes a high-temperature gas output zone (21), a generator body (22), and a heat exchange gas inlet zone (23); the high-temperature gas output zone (21) extends into the rotary kiln body (1); the generator body (22) is provided with two temperature measuring holes, the first temperature measuring hole (221) is located at half the axial length of the generator body (22), and the second temperature measuring hole (222) is located at one-quarter of the axial length of the generator body (22) near the rotary kiln body (1); the first thermometer (34) and the second thermometer (32) are respectively inserted into the first temperature measuring hole (221) and the second temperature measuring hole (222) to measure the gas temperature inside the generator body (22); the heat exchange gas inlet zone (23) is connected to the air outlet of the air supply device (4); The main heating coil (61), auxiliary heating coil (62) and heat preservation heating coil (63) are fixedly installed on the inner wall of the generator body (22) and arranged in sequence along the gas flow direction. The generator body (22) is correspondingly set as the main heating zone, auxiliary heating zone and heat preservation heating zone.

2. The electrically heated rotary kiln according to claim 1, characterized in that: The electrical control device (3) includes a main heating controller (35), an auxiliary heating controller (33), a heat preservation heating controller (31), a main controller (36), and an electrical control cabinet (37). The main heating controller (35) is connected to the main heating coil (61), the auxiliary heating controller (33) is connected to the auxiliary heating coil (62), the first thermometer (34), and the air supply device (4), and the heat preservation heating controller (31) is connected to the heat preservation heating coil (63), the second thermometer (32), and the air supply device (4). The main heating controller (35), the auxiliary heating controller (33), and the heat preservation heating controller (31) are connected to the electrical control cabinet (37) through the main controller (36). The electrical control cabinet (37) provides circuit protection for the entire electric heating system.

3. The electrically heated rotary kiln according to claim 1, characterized in that: The turns ratio of the main heating coil (61), auxiliary heating coil (62), and heat preservation heating coil (63) is 4:2:

1. By rationally configuring the turns ratio of the heating coils, the supply of high-temperature gas is guaranteed and the energy consumption of the system is optimized.

4. The electrically heated rotary kiln according to claim 1 or 2, characterized in that: An insulation layer (7) is provided on the outside of the electric heating generator (2) to reduce the heat loss of the internal gas.

5. The electrically heated rotary kiln according to claim 1, characterized in that: When the first thermometer (34) shows that the detected temperature is below 350°C, the auxiliary heating controller (33) adjusts the auxiliary heating coil (62) to heat the temperature to 350°C, further heating the gas entering the auxiliary heating zone and increasing the gas temperature; at the same time, the air volume of the air supply device (4) is reduced.

6. The electrically heated rotary kiln according to claim 5, characterized in that: When the second thermometer (32) shows that the detected temperature is below 350°C, it indicates that the gas temperature about to enter the rotary kiln body (1) cannot meet the requirements of spodumene roasting. The heat preservation and heating controller (31) adjusts the heat preservation and heating coil (63) to 350°C to further heat the gas entering the heat preservation and heating zone and increase the gas temperature; and shuts off the air supply device (4).

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