Vertical electric heating roasting furnace device for pretreatment of metallurgical chemical solid waste and use method of vertical electric heating roasting furnace device

Abstract

The invention provides a metallurgical chemical solid waste pretreatment vertical electric heating roasting furnace device and a using method thereof.The furnace body is of a hollow cylindrical vertical structure, a barrel is divided into a solid reduction area, an oxidation reduction area and a furnace charge preheating area, the barrel of the solid reduction area and the barrel of the oxidation reduction area are surrounded by flat rectangular red copper pipes, and an auxiliary induction bar is arranged in the center of the barrel; and the feeding and discharging device is connected to the PLC automatic control module. The power supply control and heat supply device is connected with the red copper pipe through a silicon controlled rectifier medium-frequency power supply, and an air supply and exhaust device, a temperature control device and a sealing device are additionally arranged. Fossil fuel is replaced by electric heating, carbon emission is reduced, environmental protection is achieved, temperature control is accurate, heat efficiency is high, and energy consumption and cost can be saved. One set of equipment is suitable for different solid waste raw materials, pretreated products are obtained through different roasting methods, the equipment is simple, investment is saved, the technological process is short, applicability is high, heating is even through the structural design, sealing is good, continuous production can be achieved, and heat efficiency and production efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of metallurgical and chemical solid waste resources, and in particular to a vertical electric heating roasting furnace device for pre-treating metallurgical and chemical solid waste and a method for using the same. Background Art

[0002] In metallurgical engineering, whether it's nonferrous or ferrous metallurgy, or whether it's hydrometallurgy or pyrometallurgy, pretreatment of the raw materials is required before smelting to change their physical and chemical structure, facilitating the smooth progress of subsequent smelting steps and achieving the desired smelting goals. Material pretreatment typically includes crushing, ball milling, pelletizing, and roasting, with high-temperature roasting being the most critical and core step. Other steps primarily alter the physical appearance of the material to prepare it for roasting, while roasting not only changes its physical structure but also its chemical composition, creating the necessary conditions for smelting.

[0003] For the pyrometallurgical process, a single oxidizing hearthstone raw material can be solid-state reduced roasted or sintered in a single smelting gold roasting equipment; sulfide ores must first be oxidized roasted for desulfurization, and then solid-state reduced roasted in another set of equipment, or directly put into smelting, but the energy consumption is relatively high. In the wet process, the roasting step is used to change the chemical structure of the material, turning it into soluble salts and insoluble compounds. The solid waste in the chemical industry is mainly waste catalysts with high utilization value. The purpose of its roasting is similar to that of the wet process. High-temperature roasting pretreatment creates conditions for the next wet smelting leaching process. Common roasting methods include sulfidation roasting, sodium roasting, and chlorination roasting.

[0004] Traditional metallurgical roasting equipment, such as rotary kilns, shaft furnaces, and fluidized bed furnaces, primarily utilizes fossil fuels (coal, natural gas, etc.) for heating. In recent years, in the nonferrous metallurgical sector, where single-unit production capacity requirements are low, electrically heated rotary kilns have emerged to replace traditional rotary kilns for solid-state reduction roasting of oxidized ores. This represents significant progress in energy conservation and environmental protection, but it is only applicable to single oxidized ores. However, the chemical composition of metallurgical and chemical solid waste is more complex, particularly solid waste generated by nonferrous metal smelting and spent catalysts from the chemical industry, which often contain oxides, sulfides, and phosphides, and the valuable metal elements present in these wastes have high recycling value. Therefore, the development of a roasting apparatus and process for the pretreatment of these metallurgical and chemical solid waste resources is of great practical and economic significance. Summary of the Invention

[0005] The purpose of the present invention is to provide a vertical electric heating roasting furnace device for pre-treating metallurgical and chemical solid waste and a method for using the same, so as to complete the entire process of oxidation (or sodiumization, chlorination, sulfidation) roasting and solid-state reduction roasting in one set of equipment, thereby effectively pre-treating solid waste and recovering valuable metal elements in the solid waste with high value and high efficiency.

[0006] According to one object of the present invention, the present invention provides a vertical electric heating roasting furnace device for pre-treating metallurgical and chemical solid waste, comprising: The furnace body is a hollow cylindrical vertical structure, including a cylinder, a loading device, and a discharge device. The cylinder is divided into three sections from bottom to top: a solid-state reduction zone, an oxidation-reduction zone, and a charge preheating zone. The cylinders of the solid-state reduction zone and the oxidation-reduction zone are surrounded by flat rectangular copper tubes. An auxiliary induction rod is provided in the center of the cylinder. The loading device is provided on one side and the top of the cylinder, and the discharge device is provided at the bottom of the cylinder. The loading device and the discharge device are connected to a PLC automatic control module. The power supply control and heating device adopts a thyristor medium frequency power supply device and is connected to the copper tube surrounding the cylinder; Air supply and exhaust devices, including furnace bottom air supply system and furnace top exhaust system; A temperature control device, comprising a temperature regulator and temperature sensors installed at each section of the cylinder, the temperature sensors being connected to the temperature regulator, which in turn is connected to the thyristor medium-frequency power supply device; Sealing device, including furnace top seal and furnace bottom seal.

[0007] Furthermore, the loading device includes a furnace top charging bell and a loading inclined bridge trolley, and the unloading device includes a unloading hopper and an automatic unloading valve.

[0008] Furthermore, the cylinder is made of 310S stainless steel and is provided with an aluminum silicate refractory fiber felt insulation layer.

[0009] Furthermore, the auxiliary sensing rod is made of 310S stainless steel.

[0010] Furthermore, the furnace bottom air supply system includes a fan, an annular main air duct and several branch air ducts. The fan is connected to the annular main air duct, and one end of several branch air ducts is connected to the annular main air duct. The branch air ducts are inserted into the storage bin of the unloading device at an angle of 30°-45° to supply air.

[0011] Furthermore, the furnace top seal includes a double 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-state reduction, the air supply pipeline is closed and the nitrogen pipeline is opened.

[0012] Furthermore, the temperature control device collects signals through the temperature sensor, compares them with the temperature setting value, and controls the input power of the thyristor medium frequency power supply device through the temperature regulator to achieve precise control of the furnace temperature between 400°C and 1100°C.

[0013] According to another object of the present invention, the present invention provides a method for using the vertical electric heating roasting furnace device, comprising the following steps: Step (1), testing and analyzing metallurgical and chemical solid waste, and classifying and stacking it; Step (2), grinding and drying the solid waste to a moisture content of ≤15%; Step (3), determining the ratio of carbonaceous reducing agent and binder according to the chemical composition to make balls, with a ball size of 20-40 mm; Step (4), drying the pellets until the moisture content is ≤5%; Step (5): Place ignition wood and coal at the bottom of the furnace, ignite them, and start the air supply system. After the coal turns red, turn on the heating device, adjust the temperature to 600°C, increase the air supply, and start the loading device to load the coal. Step (6): after the material is fully loaded, oxidation roasting and / or solid-state reduction roasting is performed according to the material conditions; Step (7): After the roasting is completed, the unloading device and the loading device are turned on to enter the next cycle of continuous production.

[0014] Furthermore, in the step (6), when the material is mainly composed of metal oxides and has a low sulfur content, solid-state reduction roasting is directly carried out, the temperature is controlled at 800-900°C, the air supply system is closed, the nitrogen seal is opened, and the roasting time is 1.5-4 hours; in the step (6), when the material needs oxidation roasting, desulfurization and solid-state reduction, the fan is first turned on according to the sulfur content to carry out oxidation roasting for 1-2 hours, the reduction stage temperature is 950°C, and after the oxidation roasting is completed, the fan is turned off, the bottom seal is opened, and solid-state reduction roasting is carried out for 1.5-2 hours; in the step (6), when the material only needs oxidation, sodiumization, chlorination or sulfurization roasting, air is supplied according to the preset air volume, there is no need to close the air supply system and open the bottom seal, and the roasting time is 2-4 hours.

[0015] Furthermore, the furnace bottom air supply system adopts oxygen-enriched blast during oxidation roasting.

[0016] The technical solution of the present invention uses electric heating to replace fossil fuels, which reduces carbon emissions and is environmentally friendly; the temperature control is precise, the thermal efficiency is high, and energy consumption and costs can be saved; a set of equipment can be used for different solid waste raw materials to obtain the required pretreated products through different roasting methods, the equipment is simple, the investment is low, the process flow is short and the applicability is strong; its structural design ensures uniform heating and good sealing, and can also produce continuously, thereby improving the thermal efficiency and production efficiency of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the structure of an embodiment of the present invention; Figure 2 For the embodiment of the present invention Figure 1 Schematic cross-section of the middle BB; Figure 3 For the embodiment of the present invention Figure 1 Schematic diagram of the cross-sectional structure of AA; Figure 4 This is a block diagram of the thyristor power supply and control structure according to an embodiment of the present invention; In the figure: 1. Cylinder; 2. Copper tube; 3. Insulating column; 4. Auxiliary induction rod; 5. Support rod; 6. Furnace top bell; 7. Loading inclined bridge trolley; 8. Loading bin; 9. Unloading hopper; 10. Automatic unloading valve; 11. Discharging trolley; 12. Annular main air duct; 13. Branch air duct; 14. Fan; 15. Furnace top exhaust device; 16. Thyristor medium frequency power supply device; 17. Temperature sensor; 18. Nitrogen pipeline; 19. Nitrogen device; 20. Insulation layer. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0022] Example 1 like Figure 1-Figure 4 As shown, a vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste includes a furnace body, a loading and unloading device, a power supply control and heating device, an air supply and exhaust device, a temperature control device and a furnace body sealing device, and each part is connected to each other in sequence, wherein: 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-state reduction zone, an oxidation-reduction zone, and a charge preheating zone. The cylinders of the solid-state reduction zone and the oxidation-reduction zone are surrounded by a flat rectangular copper tube 2 and connected to a thyristor medium-frequency power supply device. The copper tube 2 is cooled by water. The cylinder 1 is flange-connected 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 and secured to the surrounding copper tube 2 by fixed insulating columns 3. An insulating layer 20 made of aluminum silicate refractory fiber felt is provided on the outside of the cylinder 1. The center of the cylinder 1 (furnace core) is provided with a furnace core auxiliary induction heating device, which is an auxiliary induction rod 4. The auxiliary induction rod 4 is made of 310S stainless steel. The stainless steel rod is welded with 4-8 support rods 5 that are shifted at 90 degrees. They are placed upright in the furnace core according to the reduction zone and the oxidation zone. The length of the support rod 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 in the furnace uniform.

[0023] The loading and unloading device includes a loading device and a unloading device. The loading device includes a furnace top charging bell 6, a loading inclined bridge trolley 7 and a loading bin 8. The bottom of the loading inclined bridge trolley 7 is connected to the loading bin 8, and the top of the loading inclined bridge trolley 7 is located above the furnace top charging bell 6. The loading inclined bridge trolley 7 moves the material in the loading bin 8 upward at a uniform speed, and enters the interior of the furnace body through the furnace top charging bell 6. The furnace top charging bell 6 is controlled by the loading control machinery.

[0024] The unloading device includes a hopper 9 and an automatic unloading valve 10. The automatic unloading valve 10 is located at the bottom of the hopper 9. A discharge vehicle 11 is installed at the bottom of the hopper 9 to transport the discharged materials. The loading and unloading devices are connected to a PLC automatic control module, which can automatically perform loading and unloading operations according to preset process conditions.

[0025] Power supply control and heating device: The power supply heating device adopts a thyristor medium frequency power supply device 16, which is equipped with a power regulation and control system, a temperature regulation and control system. Through the temperature feedback signal inside the furnace, the input power is controlled and adjusted to control the temperature inside the furnace. The medium frequency power supply output is connected to the water-cooled short induction coil surrounding the cylinder.

[0026] In this embodiment, Figure 4 As shown in the figure, the typical structural block diagram of thyristor power supply and control, the functions of each part are as follows: The rectifier uses devices such as thyristors (SCRs) to convert three-phase industrial frequency AC power into DC. The rectifier control circuit changes the voltage, current and other parameters of the DC output by adjusting the trigger angle of the thyristors.

[0027] The filter filters the rectified DC, removing ripples in the voltage and current to make the DC smoother. Common forms include capacitor filtering, inductor filtering, or LC filtering.

[0028] The inverter converts the filtered DC into AC that meets the load requirements (it may also be a power supply with a specific frequency and waveform). The inverter control circuit is responsible for controlling the inversion process and determining the frequency, voltage, phase, etc. of the output AC.

[0029] The copper pipe, as the load in this embodiment, is the final power supply target, receiving power from the inverter to power the copper pipe. The entire system achieves power conversion and precise regulation through the coordination of rectification and inversion control circuits.

[0030] Air supply and exhaust device: The air supply is divided into four branch air ducts 13 by the annular main air duct 12 at the bottom of the furnace body and inserted into the discharge hopper 9 of the discharge device at an angle of 30°-45° for air supply. The fan 14 adopts 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 exhaust device 15 on the furnace top adopts an ordinary centrifugal exhaust fan. The exhausted flue gas enters the desulfurization and dust removal device for treatment.

[0031] Temperature Control: Temperature sensors 17 installed in the oxidation, solid-state reduction, and preheating sections of the cylinder 1 collect temperature signals and transmit them to the temperature control and display screen. The oxidation and reduction section temperatures are connected to the power regulation and control system of the thyristor medium-frequency power supply unit 16 via temperature controllers. The furnace temperature is controlled and adjusted by controlling the input power.

[0032] Furnace body sealing device: The sealing device is divided into top loading seal and bottom unloading seal. The top seal is achieved by the dual top charging bell 6 in the furnace top loading device. The bottom seal is achieved by welding the bottom nitrogen pipeline 18 to the annular main air duct 12 of the air supply device in parallel. The nitrogen pipe gate valve and the air duct 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.

[0033] Specifically, when the double furnace top charging bell 6 is working, the material cart finishes loading, the small bell located above is opened, the raw materials fall into the large bell, and the small bell is closed; then the large bell is opened, the material falls into the preheating zone in the furnace, and the large bell is closed; repeat the above procedure, load the materials, open the small bell, close the small bell, then open the large bell, load the materials, and each time there is always one bell closed to achieve a better furnace top sealing effect.

[0034] The working principle of the vertical electric heating roasting furnace device in this embodiment is as follows: The heating power supply equipment of the roasting furnace of the present invention adopts a thyristor medium-frequency power supply device. Based on the principle of electromagnetic induction heating, the electromagnetic induction coils surrounding the oxidation section and reduction section of the furnace barrel are used to perform electromagnetic induction heating on the barrel and the auxiliary induction heating rods in the furnace core, thereby generating high temperature to roast the solid waste pellets mixed with a carbonaceous reducing agent. The roasting temperature can be adjusted and automatically controlled between 400°C and 1100°C.

[0035] Working principle of the temperature control device: The temperature sensor installed in the cylinder compares the temperature signal with the temperature set value, and the temperature regulator superimposes the temperature difference signal on the constant voltage or constant power control system in the intermediate frequency device, and achieves precise temperature control by adjusting the input voltage or output power.

[0036] The air supply system at the bottom of the furnace body primarily provides oxygen during oxidation roasting (or sodium dephosphorization roasting, desulfurization roasting, etc.). The air supply system can employ oxygen-enriched blasting based on the oxygen demand for oxidation roasting. When oxidation roasting is complete and solid-state reduction roasting is required, the air supply system is shut down, allowing solid-state reduction roasting to proceed in a sealed environment. The top exhaust system, connected to the top exhaust pipe and the furnace top, directs the roasting flue gas through the preheating zone, where it is then discharged into the roasting equipment's dust removal system for purification and discharge after meeting emission standards.

[0037] The function of the sealing device of the roasting furnace is: when oxidizing roasting, close the nitrogen pipeline and open the fan pipeline to supply air; when solid-state reduction is performed, close the fan and open the nitrogen pipeline to fill it with nitrogen for bottom sealing to prevent oxygen in the air from entering the reduction section of the furnace and oxidizing the material that has completed solid-state reduction.

[0038] The loading device and the unloading device are linked by a chain mechanism. When discharging at the preset discharging time, the loading trolley automatically loads the materials, realizing timed discharging and loading, thus achieving continuous and uninterrupted production and improving the thermal efficiency and production efficiency of the equipment.

[0039] The method for using the vertical electric heating roasting furnace device of this embodiment in the pretreatment of metallurgical and chemical solid waste includes the following steps: Metallurgical and chemical solid waste is tested, analyzed, classified and stacked.

[0040] Grind any type of solid waste (part with particle size larger than 100 mesh), and if the moisture content is ≥15%, dry it to ≤15% (H2O should be controlled at 12% first).

[0041] According to the chemical composition of the material dried to H2O≦15%, the proportion of carbonaceous reducing agent (smokeless pulverized coal or coke powder) and the amount of binder are determined for compounding and pelletizing. The pellet size is Ф20-40mm.

[0042] Dry the prepared balls until the moisture content is ≤ 5% and set aside.

[0043] After checking that all mechanical and electrical equipment are normal, place a 20 cm thick ignition wood block on the bottom of the roasting furnace, then put a 30 cm thick lump of coal (20-40mm) or coke, then ignite the wood block, turn on the air supply system fan to send a small wind, wait until the coal block 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 on the top of the furnace, and start the feeding device to load the prepared small pellets.

[0044] After the cylinder is filled with materials, operate according to the different conditions of the pellet materials: A. If the pellet material is primarily composed of metal oxides, with low levels of other sulfur and other substances, oxidation roasting is not necessary and solid-state reduction can be performed directly. Adjust the temperature to 800-900°C, turn off the blower, and seal the bottom with nitrogen. Solid-state reduction roasting can be performed. The roasting time is 1.5-4 hours before discharging. The specific time depends on the metal oxide content of the material, which is directly proportional to the roasting time.

[0045] B. If the material requires both oxidation roasting and desulfurization and solid-state reduction, the fan should be turned on according to the sulfur content of the material, and sufficient air volume should be supplied according to the preset conditions. Oxidation roasting should be carried out for 1-2 hours, and the temperature of the reduction section should be controlled at 950°C. After the material in the bottom reduction section completes oxidation roasting before the oxidation section, the air supply system should be turned off, the bottom seal should be opened, and solid-state reduction roasting should be carried out for 1.5-2 hours, completing the roasting cycle and discharging the material.

[0046] C. If the material does not require solid-state reduction and only requires oxidation (or sodiumization, 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.

[0047] After the roasting time is completed in any of the three material conditions, the unloading and loading devices are opened to carry out the unloading and loading operations and enter the next roasting cycle. This cycle is repeated to achieve 24-hour three-shift continuous production.

[0048] Example 2 Roasting pretreatment of metallurgical dust and sludge in steel plants This embodiment takes the metallurgical dust sludge (converter and electric furnace dust removal ash) of a steel plant as an example. The main chemical components of the dust sludge mixture are shown in Table 1 below:

[0049] According to the chemical composition in Table 1, the solid waste has low sulfur content and is mainly composed of iron oxides. The main purpose is to utilize and recover the iron resources in the solid waste. Therefore, solid-state reduction roasting is directly carried out in the pretreatment. The specific operation steps are as follows: According to Table 1, 7% coke powder and 3% binder are added, that is, dust mud: coke powder: binder = 100:7:3 (dry basis weight ratio), of which the fixed sulfur of coke powder = 82%.

[0050] The above formula is used to make balls with a particle size of 20-40 mm, and then dried to a moisture content of H2O < 5% for later use.

[0051] After checking that the equipment is normal, place a 20 cm thick ignition wood block on the bottom of the roaster, then put in a 30 cm thick smokeless coal block, ignite the wood block and send a small air flow. After the coal block burns red, start the feeding device and load the spare balls.

[0052] After the 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℃, turn off the air supply system after roasting for about 30 minutes, and turn on the nitrogen sealing device at the bottom of the furnace.

[0053] The furnace temperature was adjusted to 900°C and the sintering was carried out for 2 hours.

[0054] After roasting at 900℃ for 2 hours, the unloading device is opened to discharge the material, and the material is loaded through the unloading chain mechanism at the same time. The solid-state reduction roasting cycle is 3 hours, and the material is discharged and loaded successively to achieve continuous and uninterrupted production.

[0055] Example 3 Pretreatment of waste residue from Baotou rare earth hydrometallurgy Taking Baotou rare earth hydrometallurgical waste slag as an example for pretreatment, its main chemical composition is shown in Table 2 below:

[0056] According to the components in Table 2, this roasting pretreatment mainly involves oxidative roasting for desulfurization and solid-state reduction roasting of Fe2O3. The specific operating steps are as follows: The waste residue is dried to H2O < 15% (preferably 12%).

[0057] According to the Fe2O3 content in the chemical composition table, the waste residue: reducing agent: binder = 100:3:3.5, of which the fixed carbon content of pulverized coal is 70% and the binder is an organic binder.

[0058] Make balls according to the above formula, with a particle size of 20-40mm, and dry the balls until the moisture content is <5% for later use.

[0059] After checking that the equipment is normal, follow step 3 of Example 2.

[0060] Fill the pellets, increase the air volume to the rated value, start the thyristor medium frequency device, and roast at full load. The temperature of the oxidation section is adjusted to 800℃, and the temperature of the reduction section is adjusted to 900℃. Oxidation roasting and desulfurization are carried out for about 2.5 hours. At this time, the oxidation roasting in the reduction section is completed before the oxidation section. Turn off the fan, open the bottom seal, and the reduction section enters solid-state reduction before the oxidation section. The CO2 generated by solid-state reduction goes to the oxidation section to supplement the oxygen demand for oxidation roasting in the oxidation section. The solid-state reduction lasts about 1.5 hours.

[0061] After step 5 is completed, the unloading and loading systems are turned on to perform unloading and loading operations to complete the roasting cycle. This cycle is repeated to achieve uninterrupted continuous production.

[0062] Example 3 Sodium Calcination of Waste Catalysts Containing Nickel and Molybdenum in the Petrochemical Industry Taking the waste catalyst containing nickel and molybdenum in the petrochemical industry as an example, sodium roasting was carried out, and its main chemical composition is shown in Table 3 below:

[0063] This embodiment adopts sodium calcination to convert phosphorus oxide in the material into soluble sodium phosphate salt, and then dephosphorizes it through hydrolysis in the next step. At the same time, SO3 in the material is removed during the calcination process. Sodium carbonate Na2CO3 is selected as the sodium calcination agent. The specific operation steps are as follows: Dry the material until the water content is about 12%.

[0064] According to 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.

[0065] The ball making steps are the same as those in Example 2.

[0066] The preliminary preparation steps are the same as those in Example 2.

[0067] The balls are filled, the air volume is gradually increased to full load, the thyristor heating device is turned on for heating, and the temperature in both the reduction section and the oxidation section is controlled at 850°C for sodium roasting, and the roasting time is about 4 hours.

[0068] After 4 hours of sodium roasting, the unloading and loading devices are started to carry out unloading and loading operations, with each 4 hours being a roasting cycle, and continuous and uninterrupted production.

[0069] Compared to traditional metallurgical furnaces for raw material pretreatment, the vertical electrically heated roasting furnace device of this invention uses an electric heating source instead of a fossil fuel combustion heat source, reducing carbon emissions and being more environmentally friendly. It offers precise temperature control and high thermal efficiency, saving energy and costs. It has a wide range of applications: a single set of equipment can be used to implement different roasting methods for different solid waste raw materials, yielding the desired pretreated roasted products. Furthermore, the device is simple, requires little investment, has a short process flow, and is highly adaptable.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste, characterized in that: include: The furnace body is a hollow cylindrical vertical structure, including a cylinder, a loading device, and a discharge device. The cylinder is divided into three sections from bottom to top: a solid-state reduction zone, an oxidation-reduction zone, and a charge preheating zone. The cylinders of the solid-state reduction zone and the oxidation-reduction zone are surrounded by flat rectangular copper tubes. An auxiliary induction rod is provided in the center of the cylinder. The loading device is provided on one side and the top of the cylinder, and the discharge device is provided at the bottom of the cylinder. The loading device and the discharge device are connected to a PLC automatic control module. The power supply control and heating device adopts a thyristor medium frequency power supply device and is connected to the copper tube surrounding the cylinder; Air supply and exhaust devices, including furnace bottom air supply system and furnace top exhaust system; A temperature control device, comprising a temperature regulator and temperature sensors installed at each section of the cylinder, the temperature sensors being connected to the temperature regulator, which in turn is connected to the thyristor medium-frequency power supply device; Sealing device, including furnace top seal and furnace bottom seal.

2. The vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste according to claim 1, characterized in that: The loading device includes a furnace top charging bell and a loading 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 pre-treatment of metallurgical and chemical solid waste according to claim 1, characterized in that: The cylinder is made of 310S stainless steel and is provided with an aluminum silicate refractory fiber felt insulation layer.

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

6. The vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste according to claim 5, characterized in that: The furnace top seal includes a double 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-state reduction, the air supply pipeline is closed and the nitrogen pipeline is opened.

7. The vertical electric heating roasting furnace device for pre-treatment 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 setting value, and controls the input power of the thyristor medium frequency power supply device through the temperature regulator to achieve precise control of the furnace temperature between 400°C and 1100°C.

8. The method for using the vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step (1), testing and analyzing metallurgical and chemical solid waste, and classifying and stacking it; Step (2), grinding and drying the solid waste to a moisture content of ≤15%; Step (3), determining the ratio of carbonaceous reducing agent and binder according to the chemical composition to make balls, with a ball size of 20-40 mm; Step (4), drying the pellets until the moisture content is ≤5%; Step (5): Place ignition wood and coal at the bottom of the furnace, ignite them, and start the air supply system. After the coal turns red, turn on the heating device, adjust the temperature to 600°C, increase the air supply, and start the loading device to load the coal. Step (6): after the material is fully loaded, oxidation roasting and / or solid-state reduction roasting is performed according to the material conditions; Step (7): After the roasting is completed, the unloading device and the loading device are turned on to enter the next cycle of continuous production.

9. The method for using the vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste according to claim 8, characterized in that: In the step (6), when the material is mainly composed of metal oxides and has a low sulfur content, solid-state reduction roasting is directly carried out, the temperature is controlled at 800-900°C, the air supply system is closed, the nitrogen seal is opened, and the roasting time is 1.5-4 hours; in the step (6), when the material needs oxidation roasting, desulfurization and solid-state reduction, the fan is first turned on according to the sulfur content to carry out oxidation roasting for 1-2 hours, the reduction stage temperature is 950°C, and after the oxidation roasting is completed, the fan is turned off, the bottom seal is opened, and solid-state reduction roasting is carried out for 1.5-2 hours; in the step (6), when the material only needs oxidation, sodiumization, chlorination or sulfurization roasting, air is supplied according to the preset air volume, there is no need to close the air supply system and open the bottom seal, and the roasting time is 2-4 hours.

10. The method for using the vertical electric heating roasting furnace device for pre-treatment of metallurgical and chemical solid waste according to claim 1, characterized in that: The furnace bottom air supply system adopts oxygen-enriched blast during oxidation roasting.

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