A vertical electric heating roasting furnace device for metallurgical chemical solid waste pretreatment

Abstract

The utility model provides a kind of metallurgical chemical solid waste pretreatment vertical electric heating roasting furnace device, furnace body part includes cylinder, cylinder is divided into solid reduction area, oxidation-reduction zone, furnace charge preheating zone, the cylinder of solid reduction area and oxidation-reduction zone is surrounded by flat rectangular copper pipe, cylinder center is equipped with auxiliary induction bar.Power control and heating device adopt thyristor intermediate frequency power supply and connect with purple copper pipe, additionally set air supply and exhaust device, temperature control device and sealing device.The utility model replaces fossil fuel with electric heating, carbon emission reduction and environmental protection, temperature control is accurate, heat efficiency is high, and energy consumption cost can be saved.A set of equipment is applicable to different solid waste raw materials, and pretreatment products are obtained by different roasting methods, and the equipment is simple, investment is saved, process flow is short, and applicability is strong.The structure design makes heating uniform, sealing is good, can continuous production, and improves heat efficiency and production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of comprehensive utilization technology of metallurgical and chemical solid waste resources, and in particular to a vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste. Background Technology

[0002] In metallurgical engineering, whether in non-ferrous or ferrous metallurgy, or in hydrometallurgy or pyrometallurgy, pretreatment of raw materials is necessary before smelting to alter their physical and chemical structures. This facilitates subsequent smelting processes and helps achieve the desired smelting goals. Material pretreatment typically includes crushing, ball milling, pelletizing, and roasting, with high-temperature roasting being the most critical and essential step. Other steps primarily alter the physical appearance of the material to suit roasting, while roasting not only changes its physical structure but also its chemical composition, creating the necessary conditions for smelting.

[0003] For pyrometallurgical processes, single-oxide ores can be roasted or sintered in a single metallurgical roasting unit; sulfide ores require oxidative roasting for desulfurization before solid-state reduction roasting in another unit, or they can be directly fed into the smelting process, but this consumes more energy. In hydrometallurgical processes, the roasting stage is used to change the chemical structure of the materials, transforming them into soluble salts and insoluble compounds. Solid waste from the chemical industry mainly consists of waste catalysts with high utilization value. The purpose of roasting in these cases is similar to that in hydrometallurgical processes: to create conditions for the subsequent hydrometallurgical leaching process through high-temperature roasting pretreatment. Common roasting methods include sulfide roasting, sodium roasting, and chlorination roasting.

[0004] Traditional metallurgical roasting equipment, such as rotary kilns, vertical shaft furnaces, and fluidized bed furnaces, primarily uses fossil fuels (coal, natural gas, etc.) for heating. In recent years, in the non-ferrous metallurgical sector, where single-unit capacity requirements are not high, electrically heated rotary kilns have emerged as a replacement for traditional rotary kilns in solid-state reduction roasting of oxide ores. This represents significant progress in energy conservation and environmental protection, but it is only applicable to single oxide ores. However, the chemical composition of metallurgical and chemical solid waste is more complex, especially solid waste from non-ferrous metal smelting and spent catalysts from the chemical industry, which often contain oxides, sulfides, phosphides, etc., and the recovery and utilization value of valuable metal elements within them is high. Therefore, developing a roasting device and process for pre-treating such metallurgical and chemical solid waste resources has significant practical economic implications. Utility Model Content

[0005] The purpose of this utility model is to provide a vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste, so as to realize the entire process of oxidation (or sodiumization, chlorination, sulfidation) roasting and solid reduction roasting in one device, thereby effectively pretreatment of solid waste and high-value and efficient recovery of valuable metal elements in solid waste.

[0006] According to one objective of this utility model, this utility model provides a vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste, comprising:

[0007] The furnace body includes a cylinder, a charging device, and a discharging device. The cylinder is divided into three sections from bottom to top: a solid reduction zone, an oxidation-reduction zone, and a charge preheating zone. The cylinder in the solid reduction zone and the oxidation-reduction zone is surrounded by flat rectangular copper tubes. An auxiliary induction rod is provided at the center of the cylinder. The charging device is located on one side and the top of the cylinder, and the discharging device is located at the bottom of the cylinder.

[0008] The power control and heating device adopts a thyristor intermediate frequency power supply device, which is connected to the copper tube surrounding the cylinder.

[0009] Air supply and exhaust systems, including a furnace bottom air supply system and a furnace top exhaust system;

[0010] A temperature control device includes a temperature regulator and temperature sensors installed in each section of the cylinder. The temperature sensors are connected to the temperature regulator, and the temperature regulator is connected to the thyristor intermediate frequency power supply device.

[0011] Sealing devices, including furnace top seals and furnace bottom seals.

[0012] Furthermore, the feeding device includes a furnace top charging bell and a feeding inclined bridge trolley, and the unloading device includes a unloading hopper and an automatic unloading valve.

[0013] Furthermore, the cylinder is made of 310S stainless steel and is provided with an aluminum silicate refractory fiber felt insulation layer.

[0014] Furthermore, the auxiliary sensing rod is made of 310S stainless steel.

[0015] Furthermore, the auxiliary sensing rod is fixedly connected to the inside of the cylinder via a support rod, and the support rod and the auxiliary sensing rod are welded and fixed at a 90° angle.

[0016] Furthermore, the furnace bottom air supply system includes a blower, a ring-shaped main air duct, and several branch air ducts. The blower is connected to the ring-shaped main air duct, and one end of each of the branch air ducts is connected to the ring-shaped main air duct. The branch air ducts are inserted obliquely into the storage bin of the unloading device at an angle of 30°-45° to supply air.

[0017] Furthermore, the furnace top seal includes a dual-bell device, and the furnace bottom seal includes a nitrogen pipeline. The gate valves of the nitrogen pipeline and the air supply pipeline of the furnace bottom air supply system are interlocked. During oxidation roasting, the nitrogen pipeline is closed and the air supply pipeline is opened. During solid reduction, the air supply pipeline is closed and the nitrogen pipeline is opened.

[0018] Furthermore, the temperature control device collects signals through the temperature sensor, compares them with the temperature setpoint, and then controls the input power of the thyristor intermediate frequency power supply through the temperature regulator to achieve precise control of the furnace temperature between 400℃ and 1100℃.

[0019] Furthermore, the furnace body is a hollow cylindrical vertical structure.

[0020] Furthermore, the feeding device and the unloading device are connected to a PLC automatic control module.

[0021] This utility model's technical solution uses electric heating to replace fossil fuels, reducing carbon emissions and being environmentally friendly; it features precise temperature control, high thermal efficiency, and saves energy and costs; one set of equipment can obtain the required pre-treated products from different solid waste raw materials through different roasting methods; the equipment is simple, requires less investment, has a short process flow, and is highly applicable; its structural design ensures uniform heating, good sealing, and continuous production, thereby improving the equipment's thermal efficiency and production efficiency. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0024] Figure 2 This is an embodiment of the present utility model. Figure 1 Cross-sectional schematic diagram of BB;

[0025] Figure 3 This is an embodiment of the present utility model. Figure 1 A schematic diagram of the cross-sectional structure of AA.

[0026] Figure 4 This is a block diagram of the thyristor power supply and control structure according to an embodiment of the present invention;

[0027] In the diagram: 1. Cylinder; 2. Copper pipe; 3. Insulating column; 4. Auxiliary induction rod; 5. Support rod; 6. Furnace top charging bell; 7. Charging inclined bridge trolley; 8. Charging bin; 9. Discharge hopper; 10. Automatic discharge valve; 11. Discharge trolley; 12. Annular main air duct; 13. Branch air duct; 14. Fan; 15. Furnace top exhaust device; 16. Thyristor intermediate frequency power supply device; 17. Temperature sensor; 18. Nitrogen pipeline; 19. Nitrogen device; 20. Insulation layer. Detailed Implementation

[0028] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" 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; 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.

[0031] Example 1

[0032] like Figures 1-4 As shown, a vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste includes a furnace body, a feeding and unloading device, a power control and heating device, an air supply and exhaust device, a temperature control device, and a furnace body sealing device. These parts are connected sequentially to each other.

[0033] The furnace body is a hollow cylindrical vertical fixed structure, specifically including a cylinder 1. The cylinder 1 is divided into three sections from bottom to top: a solid reduction zone, an oxidation-reduction zone, and a furnace charge preheating zone. The cylinders of the solid reduction zone and the oxidation-reduction zone are surrounded by flat rectangular copper tubes 2 and connected to a thyristor intermediate frequency power supply device. The copper tubes 2 are cooled by water.

[0034] The cylinder 1 is connected by flanges in three sections: preheating, oxidation and reduction. It can be disassembled and assembled for easy maintenance. The cylinder 1 is made of 310S stainless steel and is insulated from the surrounding copper tube 2 by fixed insulating column 3 and the copper tube 2 is fixed. The outer side of the cylinder 1 is provided with a heat insulation layer 20 made of aluminum silicate refractory fiber felt.

[0035] A furnace core auxiliary induction heating device is connected to the center of the cylinder 1 (furnace core). The furnace core auxiliary induction heating device is an auxiliary induction rod 4, which is made of 310S stainless steel. The stainless steel rod is welded to 4-8 support rods 5 that are offset at a 90° angle. They are placed upright in the furnace core according to the reduction zone and the oxidation zone. The length of the support rods 5 is the same as the inner diameter of the cylinder 1 to accelerate the heating speed of the furnace core material and make the heat temperature distribution in the furnace uniform.

[0036] The feeding and unloading device includes a feeding device and an unloading device. The feeding device includes a furnace top bell 6, a feeding inclined bridge trolley 7 and a feeding bin 8. The bottom of the feeding inclined bridge trolley 7 is connected to the feeding bin 8, and the top of the feeding inclined bridge trolley 7 is located above the furnace top bell 6. The feeding inclined bridge trolley 7 pushes the material in the feeding bin 8 upward at a uniform speed and enters the furnace body through the furnace top bell 6. The furnace top bell 6 is controlled by the feeding control mechanism.

[0037] The unloading device includes a discharge hopper 9 and an automatic discharge valve 10. The automatic discharge valve 10 is located at the bottom of the discharge hopper 9, and a discharge cart 11 is located at the bottom of the discharge hopper 9 to transport the discharged material away. The feeding device and the unloading device are connected to a PLC automatic control module, which can automatically perform feeding and unloading operations according to the preset process conditions.

[0038] Power supply control and heating device: The power supply heating device adopts a thyristor intermediate frequency power supply device 16. This part is equipped with a power regulation and control system and a temperature regulation and control system. Through the furnace temperature feedback signal, the input power is controlled and adjusted to control the furnace temperature. The intermediate frequency power supply output is connected to the water-cooled short induction coil surrounding the cylinder.

[0039] In this embodiment, as Figure 4 The diagram shown is a typical block diagram of a thyristor power supply and control system. The functions of each part are as follows:

[0040] A rectifier uses devices such as silicon controlled rectifiers (SCRs) to convert three-phase AC power into DC power. The rectifier control circuit changes the DC output voltage, current and other parameters by adjusting the firing angle of the SCRs.

[0041] Filters filter the rectified DC to remove ripples in the voltage and current, making the DC smoother. Common forms include capacitor filtering, inductor filtering, or LC filtering.

[0042] The inverter converts the filtered DC power back into AC power that meets the load requirements (or may be a power supply with a specific frequency and waveform). The inverter control circuit is responsible for controlling the inverter process and determining the frequency, voltage, phase, etc. of the output AC power.

[0043] The copper tube, as the load in this embodiment, is the final power source, receiving electrical energy from the inverter to power it. The entire system achieves energy conversion and precise control through the coordinated operation of the rectification and inversion control circuits.

[0044] Air supply and exhaust system: Air is supplied from the main annular air duct 12 at the bottom of the furnace body, which is divided into four branch air ducts 13, which are inserted into the unloading hopper 9 of the unloading device at an angle of 30°-45°. The equipped fan 14 is a 4-72 type high-efficiency medium and low pressure centrifugal fan or any other type of medium and low pressure fan. The fan 14 is equipped with a frequency converter to control and adjust the air volume. The furnace top exhaust system 15 is a common centrifugal exhaust fan. The exhaust gas enters the desulfurization and dust removal device for treatment.

[0045] Temperature control device: Temperature signals are collected by temperature sensors 17 installed in the oxidation section, solid reduction section and preheating section of the cylinder 1 and transmitted to the temperature control and display screen. Among them, the temperature of the oxidation section and the reduction section are connected to the power regulation and control system of the silicon controlled rectifier intermediate frequency power supply device 16 through the temperature controller, and the furnace temperature is controlled and adjusted by controlling the input power.

[0046] Furnace body sealing device: The sealing device is divided into top charging seal and bottom unloading seal. The top seal is achieved by the double furnace top charging bell 6 in the furnace top charging device; the bottom seal is achieved by welding the bottom nitrogen pipeline 18 to the annular main air pipe 12 of the air supply device. The nitrogen pipeline gate valve and the air pipe gate valve are interlocked by an interlocking mechanism. The nitrogen pipeline 18 is connected to the nitrogen device 19, and nitrogen is supplied through the nitrogen device 19.

[0047] Specifically, when the double furnace top charging bell 6 is working, after the charging car finishes charging, the small bell located above is opened, the raw material falls into the large bell, and the small bell is closed; then the large bell is opened, the material falls into the preheating zone inside the furnace, and the large bell is closed; the above procedure is repeated, charging, opening the small bell, closing the small bell, and then opening the large bell and charging, with one bell always closed each time, to achieve a better furnace top sealing effect.

[0048] The working principle of the vertical electric heating roasting furnace device in this embodiment:

[0049] The heating power supply of the roasting furnace of this utility model adopts a silicon controlled rectifier medium frequency power supply device. Based on the principle of electromagnetic induction heating, the auxiliary induction heating rods of the furnace core and the oxidation and reduction sections of the furnace body are electromagnetically induction heated by electromagnetic induction coils, thereby generating high temperature to roast the solid waste pellets mixed with carbonaceous reducing agent. The roasting temperature can be adjusted and automatically controlled between 400℃ and 1100℃.

[0050] Working principle of temperature control device: The temperature sensor installed in the cylinder compares the temperature signal with the temperature set value. The temperature regulator superimposes the temperature difference signal onto the constant voltage or constant power control system in the intermediate frequency device. The precise temperature control is achieved by adjusting the input voltage or output power.

[0051] The main function of the air supply system at the bottom of the furnace is to provide the necessary oxygen to the material when it requires oxidative roasting (or sodium dephosphorization roasting, desulfurization roasting, etc.). The air supply system can be oxygen-enriched according to the oxygen demand of oxidative roasting. When oxidative roasting is completed and solid-state reduction roasting is to be carried out, the air supply system is shut off, and solid-state reduction roasting is carried out in a closed environment. The furnace top exhaust system is connected to the furnace top exhaust pipe by a furnace top exhaust fan. It is used to discharge the roasting flue gas after preheating the material in the preheating zone. The flue gas then enters the dust removal system of the roasting equipment for purification and is discharged after meeting the standards.

[0052] The sealing device of the roasting furnace serves the following purposes: during oxidative roasting, the nitrogen pipeline is closed and the blower pipeline is opened to supply air; during solid-state reduction, the blower is closed and the nitrogen pipeline is opened to fill with nitrogen for bottom sealing, so as to prevent oxygen in the air from entering the reduction section of the furnace and oxidizing the material that has completed solid-state reduction.

[0053] The feeding and unloading devices are interlocked by an interlocking mechanism. While the material is being discharged at the preset discharge time, the feeding trolley automatically feeds the material, achieving timed discharge and timed feeding, thus enabling continuous and uninterrupted production and improving the thermal efficiency and production efficiency of the equipment.

[0054] The application method of the vertical electric heating roasting furnace in the pretreatment of solid waste in metallurgy and chemical industries, as described in this embodiment, includes the following steps:

[0055] Metallurgical and chemical solid waste is tested, analyzed, classified, and stored.

[0056] Grind any type of solid waste (part with a particle size greater than 100 mesh). If the moisture content is ≥15%, dry it to ≤15% (preferably control H2O to 12%).

[0057] Based on the chemical composition of the material dried to H2O≦15%, determine the proportion of carbonaceous reducing agent (anthracite pulverized coal or coke powder) and the amount of binder to formulate pellets with a pellet size of Ф20-40mm.

[0058] Dry the prepared balls until the moisture content is ≤5% for later use.

[0059] After checking that all mechanical and electrical equipment is in good working order, lay a 20 cm thick layer of kindling wood at the bottom of the roasting furnace, then add a 30 cm thick layer of lump coal (20-40 mm) or coke. Then ignite the wood, turn on the blower of the air supply system to blow a small amount of air, and after the coal or coke turns red, turn on the power of the heating device, adjust the temperature to 600℃, increase the air supply appropriately, turn on the exhaust fan at the top of the furnace, and start the feeding device to load the prepared small balls of material.

[0060] After the cylinder is filled with material, proceed according to the different conditions of the small balls:

[0061] A. If the pellet material is mainly composed of metal oxides with low levels of sulfur and other substances, oxidative roasting is unnecessary, and solid-state reduction can be performed directly. In this case, adjust the temperature control to between 800-900℃, turn off the blower, open the nitrogen filling device at the bottom to seal the bottom, and carry out solid-state reduction roasting. The material will be discharged after roasting for 1.5-4 hours. The specific time depends on the metal oxide content of the material, and the content is directly proportional to the roasting time.

[0062] B. If the material requires both oxidative roasting for desulfurization and solid-state reduction, the blower should be turned on according to the sulfur content of the material, and sufficient air volume should be supplied according to the preset conditions for oxidative roasting for 1-2 hours, with the temperature of the reduction section controlled at 950℃. After the material in the bottom reduction section has completed oxidative roasting before the oxidation section, the air supply system should be turned off, the bottom seal opened, and solid-state reduction roasting should be carried out for 1.5-2 hours, thus completing the roasting cycle and discharging the material.

[0063] C. If the material does not require solid reduction, but only oxidation (or sodium oxidation, chlorination, sulfidation, etc.) roasting, the air supply system will supply air at the preset air volume. There is no need to shut down the air supply system or open the bottom sealing device. The roasting time is 2-4 hours.

[0064] After the roasting time is completed in any of the three material conditions mentioned above, the unloading and loading devices are turned on to perform the unloading and loading operations, and then the next roasting cycle begins. This process is repeated to achieve continuous production in three shifts around the clock.

[0065] Example 2

[0066] Pre-treatment of metallurgical dust and sludge from steel plants

[0067] This embodiment takes metallurgical dust and sludge (converter and electric furnace dust) from a steel plant as an example. The main chemical components of the dust and sludge mixture are shown in Table 1 below:

[0068]

[0069] According to the chemical composition in Table 1, the solid waste has a low sulfur content and its main component is iron oxide. The main purpose is to utilize and recover iron resources from the solid waste. Therefore, solid-state reduction roasting is directly carried out in the pretreatment process. The specific operation steps are as follows:

[0070] According to Table 1, 7% coke powder and 3% binder are added, i.e., dust:coke powder:binder = 100:7:3 (dry basis weight ratio), of which the fixed sulfur of coke powder is 82%.

[0071] The above formula is used to make pellets with a particle size of 20-40mm, and then dried until the moisture content (H2O) is less than 5% for later use.

[0072] After checking that the equipment is working properly, lay a 20 cm thick layer of kindling wood blocks at the bottom of the roasting furnace, then put in a 30 cm thick layer of smokeless coal. After lighting the wood blocks, blow a small amount of air. Once the coal is burning red-hot, start the feeding device to load in the spare small balls.

[0073] After the small balls are filled, gradually increase the air volume to the rated value, turn on the thyristor medium frequency electric heating device, adjust the temperature to 700℃, and after roasting for about 30 minutes, turn off the air supply system and turn on the nitrogen sealing device at the bottom of the furnace.

[0074] Adjust the furnace temperature to 900℃ and roast for 2 hours.

[0075] After roasting at 900℃ for 2 hours, the unloading device is turned on to discharge the material, while the unloading interlocking mechanism is used to feed the material. The solid reduction roasting cycle is 3 hours. The material is discharged and fed in succession to achieve continuous and uninterrupted production.

[0076] Example 3

[0077] Pretreatment of waste residue from rare earth hydrometallurgical processes in Baotou

[0078] Taking the waste residue from the rare earth hydrometallurgical process in Baotou as an example for pretreatment, its main chemical composition is shown in Table 2 below:

[0079]

[0080] According to the composition in Table 2, the main pretreatment for roasting is oxidative roasting for desulfurization and solid-state reduction roasting of Fe2O3. The specific operation steps are as follows:

[0081] The waste residue is dried until H2O < 15% (preferably 12%).

[0082] Based on the Fe2O3 content in the chemical composition table, the ratio of waste residue: reducing agent: binder is determined to be 100:3:3.5, where the fixed carbon content of pulverized coal is 70% and the binder is an organic binder.

[0083] Prepare pellets according to the above formula, with a particle size of 20-40mm. Dry the pellets until the moisture content is <5% for later use.

[0084] After verifying that the equipment is functioning correctly, proceed with step 3 of Example 2.

[0085] The tubes are filled with small balls, and the airflow is turned on to the rated value. The thyristor intermediate frequency device is then turned on and roasted at full load. The temperature of the oxidation section is adjusted to 800℃, and the temperature of the reduction section is adjusted to 900℃ for oxidative roasting and desulfurization, which takes about 2.5 hours. At this time, the oxidative roasting in the reduction section is completed before that in the oxidation section. The fan is turned off, the bottom seal is opened, and the reduction section enters solid-state reduction before the oxidation section. The CO2 produced by solid-state reduction is sent to the oxidation section to supplement the oxygen required for the oxidative roasting in the oxidation section, which takes about 1.5 hours.

[0086] After step 5 is completed, the unloading and loading system is started to carry out unloading and loading operations to complete this roasting cycle. This cycle is repeated to achieve uninterrupted continuous production.

[0087] Example 3

[0088] Sodium roasting of nickel- and molybdenum-containing spent catalysts in the petrochemical industry

[0089] Taking nickel- and molybdenum-containing waste catalysts from the petrochemical industry as an example, the sodium roasting process yields the following main chemical components, as shown in Table 3:

[0090]

[0091] This embodiment uses sodium roasting to convert phosphorus oxides in the material into soluble sodium phosphate salts, followed by hydrolysis to remove phosphorus in the next step. Simultaneously, the roasting process removes SO3 from the material. Sodium carbonate (Na2CO3) is used as the sodium roasting agent. The specific operating steps are as follows:

[0092] Dry the material until the water content is about 12%.

[0093] Based on the chemical composition and process requirements in Table 3, the pelletizing formula is determined to be: catalyst: sodium carbonate: pulverized coal: binder = 100: 20: 5: 3.

[0094] The ball-making steps are the same as in Example 2.

[0095] The preliminary preparation steps are the same as in Example 2.

[0096] Fill the container with small balls, gradually increase the airflow to full capacity, turn on the thyristor heating device to provide heat, and control the temperature at 850℃ in both the reduction and oxidation stages for sodium calcination, which takes about 4 hours.

[0097] After 4 hours of sodium roasting, the unloading and loading devices are started to carry out unloading and loading operations. Each roasting cycle is 4 hours, and production is continuous and uninterrupted.

[0098] Compared with traditional metallurgical furnaces for raw material pretreatment, this utility model of a vertical electric heating roasting furnace uses an electric heating source instead of a fossil fuel combustion heat source, achieving carbon emission reduction and being more environmentally friendly. It features precise temperature control, high thermal efficiency, and saves energy and costs. It has a wide range of applications; one set of equipment can be used for different solid waste raw materials, employing different roasting methods to obtain different pretreated roasted products. Furthermore, the equipment is simple, requires low investment, has a short process flow, and is highly adaptable.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste, characterized in that, include: The furnace body includes a cylinder, a charging device, and a discharging device. The cylinder is divided into three sections from bottom to top: a solid reduction zone, an oxidation-reduction zone, and a charge preheating zone. The cylinder in the solid reduction zone and the oxidation-reduction zone is surrounded by flat rectangular copper tubes. An auxiliary induction rod is provided at the center of the cylinder. The charging device is located on one side and the top of the cylinder, and the discharging device is located at the bottom of the cylinder. The power control and heating device adopts a thyristor intermediate frequency power supply device, which is connected to the copper tube surrounding the cylinder. Air supply and exhaust systems, including a furnace bottom air supply system and a furnace top exhaust system; A temperature control device includes a temperature regulator and temperature sensors installed in each section of the cylinder. The temperature sensors are connected to the temperature regulator, and the temperature regulator is connected to the thyristor intermediate frequency power supply device. Sealing devices, including furnace top seals and furnace bottom seals.

2. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The feeding device includes a furnace top charging bell and a feeding inclined bridge trolley, and the unloading device includes a unloading hopper and an automatic unloading valve.

3. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The cylinder is made of 310S stainless steel and is equipped with an aluminum silicate refractory fiber felt insulation layer.

4. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The auxiliary sensing rod is made of 310S stainless steel.

5. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 4, characterized in that, The auxiliary sensing rod is fixedly connected to the inside of the cylinder via a support rod, and the support rod and the auxiliary sensing rod are welded and fixed at 90°.

6. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The furnace bottom air supply system includes a blower, a ring-shaped main air duct, and several branch air ducts. The blower is connected to the ring-shaped main air duct, and one end of each of the branch air ducts is connected to the ring-shaped main air duct. The branch air ducts are inserted obliquely into the storage bin of the unloading device at an angle of 30°-45° to supply air.

7. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 6, characterized in that, The furnace top seal includes a dual-bell device, and the furnace bottom seal includes a nitrogen pipeline. The nitrogen pipeline is interlocked with the gate valve of the air supply pipeline of the furnace bottom air supply system. During oxidation roasting, the nitrogen pipeline is closed and the air supply pipeline is opened. During solid reduction, the air supply pipeline is closed and the nitrogen pipeline is opened.

8. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The temperature control device collects signals through the temperature sensor, compares them with the temperature setpoint, and then controls the input power of the thyristor intermediate frequency power supply through the temperature regulator to achieve precise control of the furnace temperature between 400℃ and 1100℃.

9. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The furnace body is a hollow cylindrical vertical structure.

10. The vertical electric heating roasting furnace device for pretreatment of metallurgical and chemical solid waste according to claim 1, characterized in that, The feeding device and the unloading device are connected to a PLC automatic control module.

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