Lithium concentrate slag fluidized combustion furnace

Abstract

The present disclosure belongs to the field of nuclear power technology, and specifically relates to a lithium slag fluidized combustion furnace. The lithium slag fluidized combustion furnace includes: a feed pipe, a combustion chamber, an ignition chamber, an ignition device, an air pipe, a water jacket, and an air outlet duct; the combustion chamber is a hollow chamber, the feed pipe passes through the upper end of the combustion chamber and extends into the combustion chamber, and the other end is connected to the feed device, and an air outlet duct is provided at the upper end of the combustion chamber; the water jacket is mounted on the outer wall of the combustion chamber, a water inlet is provided on the outer side of the upper end of the water jacket, and a water outlet is provided on the outer side of the lower end of the water jacket; the ignition chamber is a hollow chamber, the lower end of the combustion chamber is connected to the upper end of the ignition chamber, and the interior of the combustion chamber is connected to the interior of the ignition chamber; the ignition needle device is arranged in the ignition chamber, and an opening is provided at the lower end of the ignition chamber; the air outlet of the air pipe passes through the lower end side wall of the ignition chamber and is located in the ignition chamber, and is used to generate an airflow that spirals upward from the bottom to the top in the ignition chamber. In this way, the lithium slag can be continuously and fully burned, overcoming the disadvantage of its easy hardening during combustion.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and in particular relates to a lithium slag fluidized combustion furnace. Background Art

[0002] Lithium slag is the residue produced during the electrolysis of lithium metal using lithium chloride and potassium chloride solutions. It contains a wide range of components, including a large amount of elemental lithium metal and smaller amounts of potassium, sodium, and their oxides and carbides. According to production statistics, approximately 0.18 tons of lithium slag are produced for every ton of lithium metal and its products. If exposed to air, this slag can react with oxygen, nitrogen, and other gases in the air, releasing heat and even spontaneously combusting. This not only wastes lithium metal but also poses a significant safety hazard to nearby equipment, facilities, and personnel.

[0003] The current method for processing lithium slag is to first store it in paraffin oil, then transport it to a large hydrolysis tank and directly plunge it into water for hydrolysis and digestion. However, the reaction between the elemental metals in the slag and water produces a large amount of hydrogen, releasing a large amount of heat. The hydrogen has a reducing effect on the paraffin oil, producing unpleasant organic matter. At the same time, when the hydrogen content in the air is 4.1% to 74.2%, it will explode when it encounters a fire source. Therefore, the large amount of heat above the hydrolysis tank and the amount of hydrogen produced are very likely to cause explosions. All of these pose great risks to the processing of lithium slag, and the hydrolysis and digestion rate is still very slow. Even after certain improvements, the maximum digestion rate is 50kg / h (kilograms per hour).

[0004] To address safety hazards during the hydrolysis and digestion of lithium slag, prevent accidents, and increase the rate of hydrolysis and digestion, a novel hydrolysis process has been proposed. This process first crushes the lithium slag into fine particles, then fully and completely combusts them. The resulting oxides are then placed in water for hydrolysis and digestion. This new process eliminates hydrogen production during the hydrolysis process and allows for easy scalability of the combustion process, enabling efficient and safe digestion and hydrolysis of lithium slag. However, achieving complete combustion of the lithium slag becomes a key technical challenge. Summary of the Invention

[0005] In order to overcome the problems existing in the related art, a lithium slag fluidized combustion furnace is provided.

[0006] According to one aspect of an embodiment of the present disclosure, a lithium slag fluidized combustion furnace is provided, the lithium slag fluidized combustion furnace comprising: a feed pipe, a combustion chamber, an ignition chamber, an ignition device, an air pipe, a water jacket, and an air outlet pipe;

[0007] The combustion chamber is a hollow chamber, one end of the feed pipe passes through the upper end of the combustion chamber and extends into the combustion chamber, the other end of the feed pipe is connected to the lithium slag conveying pipe, the feed pipe is used to introduce the lithium slag to be processed into the combustion chamber, and an air outlet pipe is provided at the upper end of the combustion chamber, and when the air outlet pipe is opened, the fluid generated in the combustion chamber can be discharged;

[0008] The water jacket is mounted on the outer wall of the combustion chamber, a water inlet is arranged on the outer side of the upper end of the water jacket, and a water outlet is arranged on the outer side of the lower end of the water jacket;

[0009] The ignition chamber is a hollow chamber, the lower end of the combustion chamber is connected to the upper end of the ignition chamber, and the interior of the combustion chamber is connected to the interior of the ignition chamber;

[0010] The ignition needle device is disposed in the ignition chamber and is used to generate a flame in the ignition chamber;

[0011] The lower end of the ignition chamber is provided with an opening for discharging the residue after the lithium slag is burned;

[0012] The air outlet of the air pipe passes through the lower end side wall of the ignition chamber and is located in the ignition chamber, and is used to generate an airflow blowing from bottom to top in the ignition chamber.

[0013] In a possible implementation, the lithium slag fluidized combustion furnace further includes a venturi tube;

[0014] The venturi tube is radially arranged, and one end of the venturi tube is communicated with the lower end opening of the ignition chamber.

[0015] In a possible implementation, the combustion chamber is divided into an upper part and a lower part in order from top to bottom, and the inner diameter of the upper part of the combustion chamber is larger than the inner diameter of the lower part of the combustion chamber.

[0016] In a possible implementation, the upper portion and the lower portion are both cylinders, and the connecting portion between the upper portion and the lower portion is an inclined surface of an inverted frustum.

[0017] In a possible implementation, the aspect ratio of the lower portion of the combustion chamber is greater than 2, and the length of the lower portion of the combustion chamber is greater than the length of the upper portion of the combustion chamber.

[0018] In a possible implementation, a transparent window is opened on the side wall of the ignition chamber.

[0019] In a possible implementation, the lithium slag fluidized combustion furnace further includes: a controller and a temperature meter;

[0020] The controller is connected to the temperature meter and the feeding device respectively, and when the temperature value obtained from the temperature meter meets the preset temperature condition, the controller controls the feeding device to start conveying lithium slag to the combustion chamber;

[0021] When the temperature value obtained from the temperature meter does not meet the preset temperature condition, the controller controls the feeding device to not operate.

[0022] In a possible implementation, the lithium slag fluidized combustion furnace further includes: a solenoid valve, a pressure gauge, and a relay control device;

[0023] The solenoid valve is connected to the air outlet duct and is used to control the opening and closing of the air outlet duct;

[0024] The relay control device is connected to the solenoid valve, and when the relay control device is energized, it can open the solenoid valve and thus open the air outlet duct;

[0025] When the pressure in the combustion chamber reaches the set value of the pressure gauge electrical contact, the pressure gauge electrical contact enables the relay control device to be energized to open the solenoid valve, so that the combustion furnace continues to exhaust until the pressure in the combustion chamber is lower than the set value of the pressure gauge electrical contact.

[0026] The beneficial effects of the present disclosure are as follows: the lithium slag fluidized combustion furnace of the present disclosure utilizes the rising hot air flow generated by the flame of the ignition device to meet the falling lithium slag material, causing the material to burn and oxidize. At the same time, air is blown into the combustion chamber at a certain air intake through the air intake pipe of the ignition chamber to generate a spiral rising air flow, which not only has the function of supporting combustion, but also slows down the speed of the falling material, prolongs the residence time of the material in the combustion chamber, and can achieve continuous and sufficient combustion of the lithium slag material, overcomes the disadvantage of easy hardening during the combustion of the refined slag, and ultimately can significantly increase the safe digestion and hydrolysis rate of the treated refined slag. The gas generated by the combustion enters the subsequent purification treatment equipment, which is conducive to improving the treatment efficiency of the refined slag. In addition, the cooling water flows from top to bottom, which is opposite to the flow direction of the hot air flow, which is conducive to removing the large amount of heat generated by the combustion of the lithium slag in the combustion chamber, effectively preventing the combustion chamber and ignition from overheating and causing explosion, and reducing the temperature of the gas-solid mixture discharged from the flue gas outlet pipe, so that the gas-solid mixture gradually shrinks in volume under the cooling effect of the water jacket, which is conducive to flue gas discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a lithium slag fluidized combustion furnace according to an exemplary embodiment.

[0028] In the picture:

[0029] 1. Feed pipe; 2. Furnace top cover; 3. Pressure gauge; 4. Temperature gauge; 5. Upper cover; 6. Water inlet; 7. Furnace outer wall; 8. Furnace inner wall; 9. Bottom of the furnace; 10. Ignition device; 11. Gas burner; 12. Gas pipe; 13. Venturi tube; 14. Inner wall of the furnace; 15. Ignition chamber; 16. Transparent window; 17. Water outlet; 18. Water jacket; 19. Combustion chamber; 20. Air outlet duct; 21. Solenoid valve. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 FIG. 1 is a schematic diagram of a lithium slag fluidized combustion furnace according to an exemplary embodiment. Figure 1 As shown, the lithium slag fluidized combustion furnace includes: a feed pipe 1, a combustion chamber 19, an ignition chamber 15, an ignition device 10, an air pipe 12, a water jacket 18 and an air outlet pipe 20;

[0032] The combustion chamber 19 is a hollow chamber, one end of the feed pipe 1 passes through the furnace top cover 2 at the upper end of the combustion chamber 19 and extends into the combustion chamber 19, the other end of the feed pipe 1 is connected to a feed device, and the feed device can input the lithium slag to be processed into the combustion chamber 19 through the feed pipe 1 (it should be noted that any form of feed device can be selected as needed, and the present disclosure does not limit the specific structure of the feed device model, as long as the feed device can transport materials to the combustion chamber). An air outlet duct 20 is provided at the upper end of the combustion chamber 19, and when the air outlet duct 20 is opened, the fluid generated in the combustion chamber 19 can be discharged;

[0033] The top end of the water jacket 18 is covered with an upper cover 5, the bottom end of the water jacket 18 is provided with a jacket bottom 9, the water jacket 18 is sleeved on the furnace outer wall 7 of the combustion chamber 19, the outer side of the upper end of the water jacket 18 is provided with a water inlet 6, and the outer side of the lower end of the water jacket 18 is provided with a water outlet 17;

[0034] The ignition chamber 15 is a hollow chamber, the lower end of the combustion chamber 19 is connected to the upper end of the ignition chamber 15, and the interior of the combustion chamber 19 is connected to the interior of the ignition chamber 15;

[0035] In a possible implementation, the combustion chamber 19 is divided into an upper part and a lower part in order from top to bottom, and the inner diameter of the upper part of the combustion chamber 19 is greater than the inner diameter of the lower part of the combustion chamber 19.

[0036] The smaller inner diameter of the lower portion of the combustion chamber 19 reduces the amount of air required for fluidization of the material in the lower portion, while the larger inner diameter of the upper portion of the combustion chamber 19 provides sufficient buffer space for the rapid expansion of the heated air. As the hotter air flows upward, it gradually contracts in volume due to the cooling effect of the water jacket 18.

[0037] In one possible implementation, the upper and lower parts of the furnace inner wall 8 of the combustion chamber 19 are both cylindrical, the connecting part between the upper and lower parts is the inclined surface of an inverted cone, and the upper and lower parts of the combustion chamber 19 are both straight sections, which further facilitates the discharge of flue gas.

[0038] In one possible implementation, the lower portion of the combustion chamber has an aspect ratio greater than 2, and the length of the lower portion is greater than the length of the upper portion. This design reduces the amount of air required for fluidization of the material in the lower portion and provides the lithium slag with more time to burn.

[0039] The ignition needle 10 device is disposed in the ignition chamber 15 and is used to generate a flame in the ignition chamber 15. For example, the structural shape of the inner wall 14 of the ignition chamber 15 can be composed of a cylinder and an inverted cone, with the lower end being an outlet for the combustion products of the lithium slag. The inner diameter of the inner wall 14 of the ignition chamber 15 can be smaller than the minimum inner diameter of the furnace inner wall 8 of the combustion chamber 19. The ignition device 10 may include an ignition needle 10 and a gas burner 11. The needle tip of the ignition needle 10 penetrates the side wall of the ignition chamber 15 and extends into the ignition chamber 15. The gas burner 11 penetrates the side wall of the ignition chamber 15 and is located in the ignition chamber 15. The needle tip of the ignition needle 10 is at the edge of the gas burner 11. The distance between the two is required to ensure the reliability of ignition.

[0040] The lower end of the ignition chamber 15 is provided with an opening for guiding out the residue after the lithium slag is burned;

[0041] The air outlet of the air pipe 12 passes through the lower side wall of the ignition chamber 15 and is located in the ignition chamber 15 , and is used to generate an airflow that spirals upward from bottom to top in the ignition chamber 15 .

[0042] In one possible implementation, the lithium slag fluidized combustion furnace further includes a venturi tube 13; the venturi tube 13 is radially arranged, and one end of the venturi tube 13 (also referred to as the suction end of the venturi tube) is connected to the lower opening of the ignition chamber 15. The negative pressure generated within the venturi tube 13 allows the combustion products to automatically and smoothly fall without the need for additional driving equipment, and are transported to the next processing step.

[0043] In one possible implementation, the lithium slag fluidized combustion furnace further includes a pressure gauge 3 disposed in the combustion chamber 19 for detecting the gas pressure in the combustion chamber 19. The pressure gauge 3 can help a worker detect the pressure condition in the combustion chamber 19 in real time.

[0044] In one possible implementation, the lithium slag fluidized combustion furnace further includes: a solenoid valve 21; the solenoid valve 21 is disposed in the air outlet duct 20, and the solenoid valve 21 can control the opening or closing of the air outlet duct 20. The air outlet duct 20 can be opened and closed by the solenoid valve 21, thereby discharging the fluid (which can be a gas or a mixture of gas and solid) generated in the combustion chamber 19 as needed.

[0045] In a possible implementation, the lithium slag fluidized combustion furnace further includes a temperature meter 4, which is disposed in the combustion chamber 19 and is used to detect the temperature in the combustion chamber 19. In this way, the temperature in the combustion chamber 19 can be observed intuitively.

[0046] In a possible implementation, a transparent window 16 is provided on the side wall of the ignition chamber 15. For example, the transparent window 16 may be made of high-temperature resistant glass, through which a worker can observe whether the ignition device 10 has ignited successfully.

[0047] In one possible implementation, the inner sidewall of the bottom end of the ignition chamber is shaped like the side of an inverted truncated cone, and the air pipe is located on a radial cross-section of the bottom end sidewall of the ignition chamber. The airflow output by the air pipe is blown out along the direction of the cross-section and rotates along the inner sidewall of the bottom end of the ignition chamber to form an ascending spiral airflow. In this way, the airflow blown out by the air pipe can automatically form an ascending spiral airflow. The ascending spiral airflow can more fully stir the falling lithium slag, which is conducive to more complete combustion of the lithium slag in the combustion chamber.

[0048] In one possible implementation, the other end of the feed pipe is located in the middle of the combustion chamber. Because the particle size of lithium slag is in the millimeter range, upward airflow can easily blow the lithium slag out of the combustion chamber. Placing the other end of the feed pipe in the middle of the combustion chamber can effectively reduce the risk of falling lithium slag being blown out of the combustion chamber by the rising airflow within the combustion chamber, and further increase the time the lithium slag remains in the combustion chamber.

[0049] In a possible implementation, the lithium slag fluidized combustion furnace further includes: a controller, an electromagnetic valve, and a pressure gauge; the pressure gauge is disposed in the combustion chamber for detecting the gas pressure in the combustion chamber; the electromagnetic valve is disposed in the air outlet duct for controlling the opening or closing of the air outlet duct; the controller is connected to the controller and the pressure gauge, respectively, and when the pressure value obtained from the pressure gauge meets the preset pressure value condition, the controller continuously controls the electromagnetic valve to open, so that the air outlet duct can discharge the gas from the combustion chamber, until the pressure value obtained from the pressure gauge by the controller does not meet the preset pressure value condition. Wherein, the pressure value meeting the preset pressure value condition can be, for example, a pressure value greater than a preset pressure threshold, or a pressure value greater than or equal to a preset pressure threshold.

[0050] In this way, the present invention can close the air outlet duct when it detects that the pressure in the combustion chamber is within the normal range (less than or equal to the preset pressure threshold) through the above-mentioned cooperation of the controller, the electromagnetic valve and the pressure gauge, thereby further allowing the material to be fully burned in the combustion chamber, and open the air outlet duct in time when it detects that the pressure in the combustion chamber is too high, thereby effectively avoiding the explosion of the combustion chamber due to excessive pressure.

[0051] In a possible implementation, the lithium slag fluidized combustion furnace further includes: a controller;

[0052] The controller is connected to the temperature meter and the feeding device respectively. When the temperature value obtained from the temperature meter meets the preset temperature condition, the controller controls the feeding device to start conveying lithium slag to the combustion chamber; wherein, the temperature value meeting the preset temperature condition can be expressed as the temperature value being greater than the preset temperature threshold or the temperature value being greater than or equal to the preset temperature threshold.

[0053] When the temperature value obtained from the temperature meter does not meet the preset temperature condition, the controller controls the feeding device to not operate.

[0054] In this way, the present disclosure can discharge materials in time when the temperature in the combustion chamber is suitable for full combustion through the cooperation of the controller, the temperature meter and the feeding device, avoiding the phenomenon that materials cannot be fully burned due to the wrong addition of materials when the temperature is too low.

[0055] In one application example, the working process of the lithium slag fluidized combustion furnace is as follows:

[0056] First, cooling water flows in through the water inlet and out from the cooling water outlet. The flow rates of inflow and outflow are adjusted to form a water jacket with stable flow.

[0057] The gas enters the combustion chamber through the pipe of the gas burner, the ignition needle works, the gas burns and releases heat, and at the same time, air flows into the ignition chamber through the gas pipe at a certain flow rate, forming an upward spiral airflow.

[0058] When the controller detects from the thermometer that the temperature inside the combustion chamber has reached the combustion temperature of lithium slag, it controls the feed device to flow a gas-solid mixture of lithium slag and air into the combustion chamber through the feed pipe. Because the temperature inside the combustion chamber has reached the combustion temperature of lithium slag and the lithium slag is lightweight and fine-grained, it ignites very quickly after entering the combustion chamber. When the particles are completely burned, the mass of the combustion products is even greater. At this time, the rising air flow is insufficient to fluidize the oxidation products. The completely burned oxidation products quickly fall to the lower port of the ignition chamber and are transported by the Venturi to the next processing step.

[0059] During the combustion of lithium slag, a large amount of oil smoke and micro-sized solid particles will be generated. The mixture of gas and solid will flow out from the flue gas outlet pipe and enter the subsequent flue gas purification process.

[0060] The lithium slag fluidized combustion furnace also includes a solenoid valve, an electric contact pressure gauge, and a relay control device. When the pressure in the combustion chamber reaches the set value of the pressure gauge's electric contact, the relay control device activates, opening the solenoid valve to exhaust the furnace and ensure furnace safety. The exhaust pressure can be changed by adjusting the set value of the pressure gauge's electric contact.

[0061] The lithium slag fluidized combustion furnace utilizes the rising hot air flow generated by the high-temperature flame during gas combustion to meet the falling material, causing the material to burn and oxidize. At the same time, air is blown into the combustion chamber at a certain air intake volume through the tangential air intake pipe of the ignition chamber to generate a spiral rising air flow. This not only has the function of assisting combustion by gas, but also the generated spiral rising air flow can fully fluidize the material and slow down the speed of the material falling, thereby extending the residence time of the material in the combustion chamber, ultimately achieving continuous and complete combustion of the lithium slag material.

[0062] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technical improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A lithium slag fluidized combustion furnace, characterized in that: The lithium slag fluidized combustion furnace comprises: a feed pipe, a combustion chamber, an ignition chamber, an ignition device, an air pipe, a water jacket and an air outlet pipe; The combustion chamber is a hollow chamber, one end of the feed pipe passes through the upper end of the combustion chamber and extends into the combustion chamber, the other end of the feed pipe is connected to the lithium slag conveying pipe, the feed pipe is used to introduce the lithium slag to be processed into the combustion chamber, and an air outlet pipe is provided at the upper end of the combustion chamber, and when the air outlet pipe is opened, the fluid generated in the combustion chamber can be discharged; The water jacket is mounted on the outer wall of the combustion chamber, a water inlet is arranged on the outer side of the upper end of the water jacket, and a water outlet is arranged on the outer side of the lower end of the water jacket; The ignition chamber is a hollow chamber, the lower end of the combustion chamber is connected to the upper end of the ignition chamber, and the interior of the combustion chamber is connected to the interior of the ignition chamber; The ignition needle device is disposed in the ignition chamber and is used to generate a flame in the ignition chamber; The lower end of the ignition chamber is provided with an opening for discharging the residue after the lithium slag is burned; The air outlet of the air pipe passes through the lower side wall of the ignition chamber and is located in the ignition chamber. The inner side wall of the bottom end of the ignition chamber is shaped like the side of an inverted cone. The air pipe is located on a section of a radial cross section of the side wall of the bottom end of the ignition chamber. The airflow output by the air pipe is blown out along the direction of the section and rotates along the inner side wall of the bottom end of the ignition chamber to form an ascending spiral airflow. The lithium slag fluidized combustion furnace further includes a venturi tube; The venturi tube is radially arranged, and one end of the venturi tube is communicated with the lower end opening of the ignition chamber.

2. The lithium slag fluidized combustion furnace according to claim 1, characterized in that: The combustion chamber is divided into an upper part and a lower part in order from top to bottom, and the inner diameter of the upper part of the combustion chamber is larger than the inner diameter of the lower part of the combustion chamber.

3. The lithium slag fluidized combustion furnace according to claim 2, characterized in that: The upper part and the lower part are both cylindrical, and the connecting portion between the upper part and the lower part is an inclined surface of an inverted frustum.

4. The lithium slag fluidized combustion furnace according to claim 2, characterized in that: The aspect ratio of the lower part of the combustion chamber is greater than 2, and the length of the lower part of the combustion chamber is greater than the length of the upper part of the combustion chamber.

5. The lithium slag fluidized combustion furnace according to claim 1, characterized in that: A transparent window is provided on the side wall of the ignition chamber.

6. The lithium slag fluidized combustion furnace according to claim 1, characterized in that: The lithium slag fluidized combustion furnace also includes: a controller and a temperature meter; The controller is connected to the temperature meter and the feeding device respectively, and when the temperature value obtained from the temperature meter meets the preset temperature condition, the controller controls the feeding device to start conveying lithium slag to the combustion chamber; When the temperature value obtained from the temperature meter does not meet the preset temperature condition, the controller controls the feeding device to not operate.

7. The lithium slag fluidized combustion furnace according to claim 1, characterized in that: The lithium slag fluidized combustion furnace also includes: a solenoid valve, a pressure gauge and a relay control device; The solenoid valve is connected to the air outlet duct and is used to control the opening and closing of the air outlet duct; The relay control device is connected to the solenoid valve, and when the relay control device is energized, it can open the solenoid valve and thus open the air outlet duct; When the pressure in the combustion chamber reaches the set value of the pressure gauge electrical contact, the pressure gauge electrical contact enables the relay control device to be energized to open the solenoid valve, so that the combustion furnace continues to exhaust until the pressure in the combustion chamber is lower than the set value of the pressure gauge electrical contact.

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