Silicon-manganese alloy casting method based on gradual change air cooling heat recovery

Abstract

The invention provides a silicon-manganese alloy casting method based on gradual change air-cooled heat recovery, which comprises the processes of smelting silicon-manganese alloy liquid, casting and molding, staged cooling and heat recovery, and comprises the following steps: smelting manganese ore, silica and a reducing agent in a fully-closed submerged arc furnace, adding 0.01-0.1 wt% of rare earth element as a refining agent, and uniformly mixing the rare earth element with the reducing agent; the temperature of the silicon-manganese alloy liquid ranges from 1500 DEG C to 1600 DEG C; the alloy liquid is poured into a mold preheated to 800-900 DEG C to form a cast ingot, and vibration auxiliary pouring is carried out in the alloy liquid pouring process; after the alloy liquid is completely poured into a mold and is initially set, gradually-changed air cooling is firstly carried out until the surface temperature of the alloy is reduced to 1000-1100 DEG C, then intermittent water cooling is carried out, and then natural cooling is carried out to the room temperature; and in the staged cooling process, hot air and steam are collected in a two-way recovery mode. The silicon-manganese alloy casting quality and production efficiency can be improved, and the practicability is high.

Description

Technical Field

[0001] This application belongs to the field of alloy smelting technology, and relates to a silicon-manganese alloy casting method, and more particularly to a silicon-manganese alloy casting method based on gradual air cooling heat recovery. Background Technology

[0002] Ferroalloy smelting, as a crucial supporting sector of the steel industry, has seen continuous optimization of its production processes with the development of steelmaking technology to meet the high-quality requirements for alloy additives. Ferromanganese alloys, as key composite deoxidizers and alloy additives, occupy a central position in the entire smelting process through casting technology. In recent years, ferroalloy casting processes have evolved from traditional manual operations towards automation and energy conservation, focusing on smelting efficiency and ingot quality control. Particular emphasis has been placed on temperature management and heat utilization during the cooling stage, which has become a critical link in improving product performance and reducing energy consumption.

[0003] Current methods for casting silicon-manganese alloys typically involve smelting the alloy in an electric arc furnace, then directly pouring the molten alloy into a mold to form the ingot, followed by cooling the ingot to achieve rapid solidification and subsequent operations. This cooling method primarily relies on heat transfer through air convection and direct water contact.

[0004] However, when the cooling process relies primarily on air convection, the cooling rate is often difficult to precisely adjust due to the low heat transfer coefficient of air, especially at high temperatures, leading to uneven heat dissipation and significant temperature gradients in different parts of the ingot. Simultaneously, when direct water contact is used for cooling, the water undergoes intense vaporization upon contact with the high-temperature ingot. While the heat transfer intensity is high, the localized effect is strong, easily causing significant differences in cooling rates between the surface and the interior. In practical applications, this single or simple combination of heat transfer methods often results in uneven internal structure of the ingot and ineffective utilization of residual heat, affecting product quality and energy efficiency. Summary of the Invention

[0005] This application provides a silicon-manganese alloy casting method based on gradual air cooling heat recovery, which solves the technical problems of uneven internal structure of ingot and difficulty in effectively utilizing residual heat during the existing silicon-manganese alloy casting cooling process.

[0006] This application provides a method for casting silicon-manganese alloy based on gradual air cooling heat recovery, including the following steps: Smelting ferrosilicon manganese alloy liquid: Manganese ore, silica and reducing agent are smelted in a fully enclosed submerged arc furnace, while rare earth elements are added as refining agents. The rare earth element content is 0.01-0.1wt%, and a ferrosilicon manganese alloy liquid with a temperature of 1500-1600℃ is obtained. Casting: The molten alloy is poured into a mold preheated to 800-900℃ to form an ingot. Vibration is used to assist in the pouring process. Staged cooling: After the molten alloy is completely poured into the mold and initially solidifies, it is first subjected to gradual air cooling until the surface temperature of the alloy drops to 1000-1100℃, followed by intermittent water cooling, and then natural cooling to room temperature; the gradual air cooling adopts a three-stage gradual decrease in wind speed and controls the duration of each stage of the gradual air cooling, and the wind speed in each stage of the gradual air cooling does not exceed 5m / s; the intermittent water cooling adopts a spray method, and the water flow rate is controlled at 10-20L / min; Heat recovery: During the phased cooling process, a dual-path recovery method is adopted to collect hot air and steam respectively. In the gradual air cooling process, hot air is collected, and the heat is recovered through a heat exchanger and used to preheat the smelting raw materials. At the same time, steam is collected during the intermittent water cooling process and converted into hot water or steam energy through a steam recovery device for plant heating or auxiliary power generation.

[0007] As an optional method of this application, the gradual air cooling is achieved by using an adjustable speed fan in conjunction with an air supply duct to connect multiple air nozzles arranged around the molded ingot to cool the molded ingot. Each air nozzle is evenly distributed around the lower side of the mold. The first stage of the gradual air cooling has an air speed of 4-5 m / s and lasts for 10-15 min; the second stage has an air speed of 2.5-3 m / s and lasts for 20-25 min; the third stage has an air speed of 1.5-2 m / s and lasts for 15-20 min. If the alloy surface temperature does not drop to 1000-1100℃ after the third stage, the air speed is reduced to below 1 m / s until the temperature reaches the target and then the air cooling is stopped.

[0008] As an alternative embodiment of this application, the number of air outlets is at least 6, and each air outlet is evenly distributed around the molded ingot and blows air onto the molded ingot in an oblique upward manner. Each air outlet is connected to the air duct connected to the adjustable speed fan.

[0009] As an optional embodiment of this application, the collection of hot air and steam is achieved by using a gas collecting hood that is installed above the molded ingot. The bottom of the gas collecting hood is provided with a collection inlet pointing downwards towards the molded ingot. The gas collecting hood is connected to two independently arranged diversion pipes. One diversion pipe is connected to a heat exchanger. During the gradual air cooling stage, hot air enters the gas collecting hood through the collection inlet and then enters the diversion pipe through a control valve and is guided to the heat exchanger for heat recovery. The other diversion pipe is connected to a steam recovery device. During the intermittent water cooling stage, steam enters the gas collecting hood through the collection inlet and then enters the diversion pipe through a control valve and is guided to the steam recovery device for conversion and utilization.

[0010] As an optional method of this application, the intermittent water-cooled spray method is to spray for 5-10 seconds with an interval of 10-15 seconds, for a total of 3-5 cycles.

[0011] As an optional method of this application, intermittent water cooling uses an atomizing nozzle for spraying, and the water mist particle size is controlled to be 50-200μm by the atomizing nozzle.

[0012] As an alternative embodiment of this application, there are at least 6 atomizing nozzles, which are evenly distributed above the molded ingot and spray the molded ingot intermittently in a downward spraying manner.

[0013] As an alternative method of this application, vibration-assisted casting is achieved by an electromagnetic vibration device installed at the bottom of the mold, with a vibration frequency of 50-100Hz and a vibration amplitude controlled at 0.5-2mm.

[0014] As an alternative to this application, the heat exchanger used is a plate heat exchanger, and the steam recovery device used is a shell and tube condenser.

[0015] As an optional embodiment of this application, the method is applicable to the production of silicon-manganese alloy with a silicon content of 17-23 wt% and a manganese content of 62-68 wt%, wherein the silicon-manganese alloy is produced in the form of ingots with a weight of 500-1500 kg and a block shape.

[0016] Compared with the prior art, this application has the following beneficial effects: 1. This application provides a silicon-manganese alloy casting method based on gradual air cooling heat recovery. This method improves upon existing silicon-manganese alloy casting processes where improper cooling control leads to uneven alloy element distribution. After the alloy molten metal is poured and undergoes initial solidification, gradual air cooling is applied until the alloy surface temperature drops to 1000-1100℃. The gradual air cooling employs a three-stage cooling control method with progressively decreasing wind speeds and controlled durations for each stage, with each stage's wind speed not exceeding 5 m / s. This gradual reduction in wind speed from high to low reduces the degree of thermal stress concentration in the high-temperature stage, decreasing the risk of rapid silicon segregation. Simultaneously, the controlled duration of each stage ensures a more uniform temperature gradient distribution, reducing the likelihood of void formation within the ingot. Subsequently, intermittent water cooling is performed, with a water flow rate controlled at 10-20 L / min, followed by natural cooling to room temperature. The intermittent spraying method slows the cooling rate in the mid-temperature stage, reducing the occurrence of localized rapid cooling cracks. The natural cooling stage helps release residual stress, improving the uniformity of alloy element distribution and thus alleviating the elemental inhomogeneity problem caused by insufficient cooling control in existing methods.

[0017] 2. This application also addresses the problem of heat waste during the cooling process through a heat recovery step. In the staged cooling process, a dual-path recovery method is used to collect hot air and steam separately. Specifically, hot air is collected during the gradual air cooling process, and its heat is recovered through a heat exchanger and used to preheat the smelting raw materials. This hot air collection and recovery method uses the hot air generated by the gradual air cooling as a heat source, completing heat transfer through the heat exchanger and directly applying it to preheat the raw materials, reducing the energy input during smelting in the electric arc furnace. Simultaneously, steam is collected during the intermittent water cooling process and converted into hot water or steam energy through a steam recovery device for plant heating or auxiliary power generation. This conversion process transforms steam into a reusable form, and combined with the utilization of hot air, it can reduce heat loss caused by the direct emission of hot air and steam, thereby improving energy utilization efficiency.

[0018] 3. This application, through the synergistic effect of smelting, casting, cooling, and heat recovery, forms a closed-loop process that improves the quality of silicon-manganese alloy casting. In the smelting step, rare earth elements are added as refining agents in a fully enclosed submerged arc furnace at a content of 0.01-0.1 wt%, which reduces the inclusion content in the alloy melt and improves the purity of the melt, providing a more stable foundation for casting. Vibration-assisted casting during the casting process promotes uniform filling of the mold with the alloy melt, which helps reduce the occurrence of initial defects and provides favorable conditions for staged cooling. In addition, the combination of gradual air cooling and intermittent water cooling ensures a smooth transition from high temperature to room temperature during the cooling process, reducing the risk of segregation and voids. Dual-path heat recovery converts the waste heat from cooling into preheating raw materials or heating energy, realizing energy recycling and thus improving the overall quality and efficiency of silicon-manganese alloy casting. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of a silicon-manganese alloy casting method based on gradual air cooling heat recovery, provided as an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0022] First, let me explain the terms used in this application: Silicon-manganese alloy: refers to an iron alloy with manganese and silicon as the main alloying elements, iron as the balance, and small amounts of impurities such as carbon, phosphorus, and sulfur. It is used as a composite deoxidizer and alloying additive in steelmaking. Submerged arc furnace: refers to a submerged arc furnace heated by an electric arc, used for ferroalloy smelting. It uses electrodes to generate a high-temperature electric arc to melt the furnace charge and carry out a reduction reaction. Fully enclosed submerged arc furnace: refers to a submerged arc furnace with a sealed furnace body and exhaust gas collection and purification, which can reduce dust emissions and recover coal gas for power generation, thereby improving environmental protection and energy utilization. Initial solidification: refers to the state in which the surface or outer layer of the molten alloy begins to solidify and form a stable outer shell after being poured into the mold; Plate heat exchanger: refers to a heat exchange device assembled from multiple corrugated plates, used for heat exchange between hot air and cold medium, and features high heat exchange efficiency and compact structure; Shell-and-tube condensers are condensation devices in which steam flows on the shell side and the cooling medium circulates on the tube side. They are used to condense steam into hot water and are characterized by their scale resistance and ease of cleaning.

[0023] This application provides a method for casting silicon-manganese alloy based on gradual air cooling and heat recovery, including processes such as smelting silicon-manganese alloy liquid, casting, staged cooling, and heat recovery. Figure 1 As shown, the specific steps of this silicon-manganese alloy casting method based on gradual air cooling heat recovery are as follows: S1. Manganese ore, silica and reducing agent are smelted in a fully enclosed submerged arc furnace, while rare earth elements are added as refining agents. The rare earth element content is 0.01-0.1wt%, and a silicon-manganese alloy liquid with a temperature of 1500-1600℃ is obtained. S2. Pour the molten alloy into a mold preheated to 800-900℃ to form an ingot. Vibration is used to assist in the pouring process. S3. After the molten alloy is completely poured into the mold and initially solidifies, it is first subjected to gradual air cooling until the surface temperature of the alloy drops to 1000-1100℃, followed by intermittent water cooling, and then natural cooling to room temperature. The gradual air cooling adopts a three-stage cooling control method with gradually decreasing air speed and controlling the duration of each stage of the gradual air cooling. The air speed in each stage of the gradual air cooling does not exceed 5m / s. The intermittent water cooling adopts a spray method with a water flow rate controlled at 10-20L / min. S4. During the phased cooling process, a dual-path recovery method is adopted to collect hot air and steam respectively. In the gradual air cooling process, hot air is collected, and the heat is recovered through a heat exchanger and used to preheat the smelting raw materials. At the same time, steam is collected during the intermittent water cooling process and converted into hot water or steam energy through a steam recovery device for plant heating or auxiliary power generation.

[0024] The silicon-manganese alloy casting method based on gradual air cooling and heat recovery provided in this embodiment can improve the uneven distribution of alloy elements caused by improper cooling control during the existing silicon-manganese alloy casting process by using a specific staged cooling method. After the alloy liquid is poured and initially solidified, it is first subjected to gradual air cooling until the alloy surface temperature drops to 1000-1100℃. The gradual air cooling adopts a three-stage cooling control method with gradually decreasing wind speed and controlling the duration of each stage. The wind speed in each stage does not exceed 5m / s. This method of gradually decreasing wind speed from high to low reduces the degree of thermal stress concentration in the high-temperature stage, reduces the risk of rapid segregation of silicon elements, and at the same time, the control of the duration of each stage makes the temperature gradient distribution more uniform, reducing the possibility of voids forming inside the ingot. Subsequently, intermittent water cooling is performed with the water flow rate controlled at 10-20L / min, followed by natural cooling to room temperature. The intermittent spraying method slows down the cooling rate in the middle temperature stage, reducing the occurrence of local rapid cooling cracks, while the natural cooling stage helps to release residual stress and improve the uniformity of alloy element distribution, thereby alleviating the element inhomogeneity problem caused by insufficient cooling control in the existing system.

[0025] Furthermore, this embodiment addresses the issue of heat waste during cooling through a heat recovery step. A dual-path recovery method is employed during the staged cooling process to collect hot air and steam separately. Hot air is collected during the gradual air cooling process, and its heat is recovered through a heat exchanger and used to preheat smelting raw materials. This hot air collection and recovery method uses the hot air generated by the gradual air cooling as a heat source, transferring heat through the heat exchanger and directly applying it to preheating raw materials, thus reducing the energy input during smelting in the electric arc furnace. Simultaneously, steam is collected during the intermittent water cooling process and converted into hot water or steam energy through a steam recovery device for plant heating or auxiliary power generation. This conversion process transforms steam into a reusable form, and combined with the utilization of hot air, it reduces heat loss caused by direct emissions of hot air and steam, thereby improving energy efficiency.

[0026] Furthermore, this embodiment utilizes the synergistic effects of smelting, casting, cooling, and heat recovery to form a closed-loop process, which improves the quality of silicon-manganese alloy casting. In the smelting step, rare earth elements are added as refining agents in a fully enclosed submerged arc furnace at a content of 0.01-0.1 wt%, reducing inclusions in the molten alloy and increasing melt purity, providing a more stable foundation for casting. Vibration-assisted casting during the pouring process promotes uniform filling of the mold with the molten alloy, reducing initial defects and providing favorable conditions for staged cooling. Additionally, the combination of gradual air cooling and intermittent water cooling ensures a smooth transition from high temperature to room temperature, reducing the risk of segregation and voids. Dual-path heat recovery converts residual cooling heat into preheating raw materials or heating energy, achieving energy recycling and thus improving the overall quality and efficiency of silicon-manganese alloy casting.

[0027] In some embodiments, gradual air cooling is achieved by using an adjustable speed fan in conjunction with an air duct connected to multiple air nozzles arranged around the molded ingot to cool the molded ingot. Each air nozzle is evenly distributed around the lower side of the mold. The first stage of gradual air cooling has an air velocity of 4-5 m / s for 10-15 min; the second stage has an air velocity of 2.5-3 m / s for 20-25 min; and the third stage has an air velocity of 1.5-2 m / s for 15-20 min. If the alloy surface temperature does not drop to 1000-1100℃ after the third stage, the air velocity is reduced to below 1 m / s until the temperature reaches the target and then air cooling is stopped.

[0028] The adjustable speed fan can be a commonly used industrial variable frequency centrifugal fan. The power is determined according to the ingot size; for example, a 30-50kW fan is selected for ingots weighing 500-1500kg. The speed is controlled by a frequency converter to achieve staged switching of the airflow. The air duct is made of galvanized steel plate or stainless steel pipe with a diameter of 200-400mm. Branch pipes branch from the fan outlet to each air outlet. Manual or electric regulating valves are installed on the branch pipes to facilitate airflow balance. Each air outlet is a conical or grooved nozzle, numbering 6-12, evenly fixed on the support around the mold, located on the lower side of the mold. The nozzles face upwards at an angle of 30-45° to allow the cool air to rise and flow along the mold surface. The alloy surface temperature is monitored by an infrared thermometer or thermocouple, with measuring points arranged at multiple locations on the mold, and the average value is used as the control basis. The temperature signal is connected to the PLC control system and linked with the fan frequency converter to achieve automatic stage switching and extended adjustment of the third stage. With this arrangement, cold air covers the mold surface evenly, while hot air rises naturally, facilitating subsequent collection.

[0029] In practice, after pouring, wait for initial setting before starting the first stage of the blower. During operation, the duration of each stage can be fine-tuned according to the actual heat dissipation of the ingot; for example, the second and third stages can be appropriately extended for larger ingots. The blower and air duct are installed on a fixed platform at the cooling station, 0.5-1m away from the mold, to avoid high-temperature radiation affecting the equipment's lifespan. The equipment required for this implementation method consists of standard metallurgical industry components, which are simple to install and adjust, and can be directly implemented by those skilled in the art according to the ingot specifications.

[0030] In some embodiments, the number of air outlets is at least 6, and each air outlet is evenly distributed around the molded ingot and blows air onto the molded ingot in an oblique upward manner. Each air outlet is connected to the air duct connected to the adjustable speed fan.

[0031] In practical applications, the air outlet can optionally be a conical nozzle made of stainless steel or heat-resistant steel, with an inner diameter of 50-100mm, and the outlet designed as a flat groove to expand the air curtain coverage area. The air outlet is connected to the main air supply duct via a branch pipe, and a manual butterfly valve is installed on the branch pipe for initial airflow balance adjustment. Furthermore, the air outlet is fixed to a movable or fixed bracket around the mold, with the bracket height adjustable so that the air outlet is located on the lower side of the mold, 200-500mm from the outer wall of the mold. The upward blowing angle is controlled at 30-45°, achieved by tilting the bracket or adjusting the nozzle direction. This angle allows the cold air to flow upward along the mold surface, promoting uniform heat removal and facilitating the upward concentration of hot air.

[0032] In actual installation, the number and spacing of air vents are first determined based on the mold size. For example, 8-12 air vents are evenly arranged for a circular mold with a diameter of 1-1.5m. The fan is placed to the side of the cooling station and connected via a galvanized steel duct. The duct is lined with heat-resistant material to reduce heat loss. Temperature monitoring uses a multi-point infrared thermometer, and the adjustable-speed fan is connected to the fan control cabinet to achieve automatic switching of wind speed stages. The components required for this arrangement are all commonly used equipment in metallurgical cooling systems, and those skilled in the art can directly select and install them according to the ingot specifications.

[0033] In some embodiments, the collection of hot air and steam is achieved by a gas collecting hood that is installed above the molded ingot. The bottom end of the gas collecting hood has a collection inlet pointing downwards towards the molded ingot. The gas collecting hood is connected to two independently arranged diversion pipes. One diversion pipe is connected to a heat exchanger. During the gradual air cooling stage, hot air enters the gas collecting hood through the collection inlet and then enters the diversion pipe through a control valve and is guided to the heat exchanger for heat recovery. The other diversion pipe is connected to a steam recovery device. During the intermittent water cooling stage, steam enters the gas collecting hood through the collection inlet and then enters the diversion pipe through a control valve and is guided to the steam recovery device for conversion and utilization.

[0034] In the above embodiments, the gas collecting hood can be welded from heat-resistant steel plate or stainless steel plate, and is in the shape of an inverted cone or square hood. The diameter of the hood opening is 200-500mm larger than the outer diameter of the mold, and the hood height is 1-2m. The bottom collection inlet is a circular or rectangular opening, and the edge of the opening extends downward to form a guide lip to guide the rising airflow into the hood. The gas collecting hood is fixed above the cooling station by a support column or hanger. The bottom of the hood and the top surface of the mold are kept at a gap of 600-1000mm, which facilitates operation and observation, and also allows hot air and steam to rise naturally into the hood. The diversion pipe is made of insulated steel pipe with a diameter of 200-400mm. Two pipes are led out in parallel from the top of the gas collecting hood. A pneumatic or electric butterfly valve is installed at the inlet of each pipe. The opening and closing are controlled by a temperature sensor or a stage timing signal to realize that the hot air path is opened during the gradual air cooling stage and the steam path is opened during the intermittent water cooling stage.

[0035] In actual operation, during the gradual air cooling stage, the hot air temperature is high and dry, and the rising airflow is relatively stable, easily entering the hood through the collection inlet and being guided to the heat exchanger via the first branch pipe. During the intermittent water cooling stage, the generated steam has high humidity and significant volume expansion, similarly concentrating upwards at the top of the hood and being guided to the steam recovery device via the second branch pipe. Valve switching can be automatically executed by the PLC system according to the cooling stage, or manually assisted in adjustment. The materials and components required for this gas collection hood and piping system are all commonly used equipment in metallurgical plants, and those skilled in the art can directly select and install them according to the ingot size and site space.

[0036] In some embodiments, the intermittent water-cooled spraying method involves spraying for 5-10 seconds with an interval of 10-15 seconds, for a total of 3-5 cycles.

[0037] Intermittent spraying can be achieved through a combination of solenoid valves or pneumatic valves and a PLC timing control system. The valves are installed on the main water supply pipe or branch pipes of each spray nozzle. The water source is the plant's circulating cooling water, with a pressure of 0.3-0.8 MPa, supplied after being stabilized by a pressure reducing valve. The PLC system controls the opening and closing of the valves according to a preset program, for example, setting the valve to close after 12 seconds of spraying, then repeating the cycle, automatically stopping after a total of 3-5 cycles. The water supply pipeline uses stainless steel or galvanized steel pipes with a diameter of 50-100 mm, connected to atomizing nozzles at the ends. Under this control method, the spraying cycle and interval can be fine-tuned based on feedback from the ingot surface temperature, for example, by monitoring the temperature change rate with an infrared thermometer and appropriately extending the interval to avoid overcooling. Those skilled in the art can use commercially available standard PLC modules and valve components, directly connecting them to the power and water supply at the cooling station for implementation.

[0038] In some embodiments, intermittent water cooling is performed using an atomizing nozzle, and the water mist particle size is controlled to be between 50-200 μm by the atomizing nozzle.

[0039] In the above embodiments, the atomizing nozzle can be a commonly used industrial pressure-type or dual-fluid atomizing nozzle. For example, a pressure-type nozzle achieves atomization through a water supply pressure of 0.3-0.8 MPa, while a dual-fluid nozzle introduces compressed air to assist atomization to obtain finer particle sizes. The nozzle material is made of stainless steel or wear-resistant ceramic, with an orifice diameter of 0.5-2 mm. With appropriate orifice diameter combinations, the water mist particle size can be adjusted to a range of 50-200 μm using pressure or compressed air. For example, using a 1 mm orifice nozzle at a water supply pressure of 0.5 MPa can obtain a particle size of approximately 100 μm. The nozzle is installed at the end of the water supply pipeline with a pipeline diameter of 50-80 mm. The number of nozzles matches the mold size, typically 6-12 evenly distributed on the upper support. The water supply system is equipped with a filter to remove impurities and a pressure-reducing valve to stabilize the pressure. The atomizing nozzles used can be commercially available products selected and installed and adjusted directly according to the ingot size.

[0040] In some embodiments, there are at least six atomizing nozzles, which are evenly distributed above the molded ingot and spray the molded ingot intermittently in a downward spraying manner.

[0041] Optionally, the atomizing nozzles can be fixed on a ring or square bracket, which is installed above the cooling station frame. The height can be adjusted so that the nozzles are 300-500mm from the top surface of the mold. The number of nozzles is determined by the mold size; for example, eight nozzles can be arranged for a mold with a diameter of 1m, evenly spaced at 45° intervals, with the nozzles pointing downwards vertically or nearly vertically towards the ingot surface. Branch pipes branch off from the main water supply pipe connect to each nozzle, and flow regulating valves are installed on the branch pipes to balance the water volume.

[0042] During actual spraying, the nozzles spray water mist downwards, forming a uniform water curtain covering the surface of the ingot. The water mist vaporizes on the high-temperature surface, absorbing heat, and the steam rises into the steam collection hood. Intermittent control is achieved by timed opening and closing of the water supply valve. The downward spray direction helps the water mist directly contact the surface, improving the heat exchange effect.

[0043] In some embodiments, vibration-assisted casting is achieved by an electromagnetic vibration device installed at the bottom of the mold, with a vibration frequency of 50-100Hz and a vibration amplitude controlled at 0.5-2mm.

[0044] Optionally, the electromagnetic vibration device can be a commonly used industrial vibration table or vibrator with a power of 10-30kW, selected according to the mold size. The device is fixed to the bottom platform of the mold by bolts or clamps, and the mold is placed on top of the vibration device. The vibration starts when the alloy liquid begins to be poured and continues until the pouring is completed. The process can be controlled by a manual switch or a PLC timer.

[0045] In practical applications, the vibration frequency can be gradually increased from 50Hz to 80-100Hz to adapt to changes in the flow of the molten alloy. Controlling the amplitude to around 1mm can reduce bubble formation. The bottom of the mold should be padded for vibration damping. Those skilled in the art can select a suitable electromagnetic vibration device based on the viscosity of the molten alloy and the mold specifications.

[0046] In some embodiments, the heat exchanger used is a plate heat exchanger, and the steam recovery device used is a shell-and-tube condenser.

[0047] In the above embodiments, the plate heat exchanger can be assembled with stainless steel corrugated plates, with a plate thickness of 0.5-0.8 mm. The heat exchange area is determined according to the ingot size; for example, a heat exchange area of ​​20-40 m² is selected for a 1000 kg ingot. 2This model features a counter-current arrangement to improve heat transfer efficiency. The hot air inlet connects to the first branch pipe of the gas collection hood, and the outlet discharges cooling air. Preheated raw material air or circulating water can be introduced into the cold medium side, with the medium flow rate controlled at 1-3 m / s. The heat exchanger is installed on the side of the cooling station and connected via insulated pipes to ensure minimal temperature loss when hot air enters. This type of heat exchanger is widely used in metallurgical waste heat recovery, and those skilled in the art can directly select suitable commercially available products based on the hot air flow rate.

[0048] For shell-and-tube condensers, fixed tube sheet or floating head structures can be selected, with tube diameters of 20-50 mm, 200-500 tubes, and shell diameters of 600-1000 mm. The steam inlet is connected to the second branch pipe of the steam collector hood. Steam flows on the shell side, while the cooling medium (cooling water) circulates on the tube side. The condensed hot water is discharged from the bottom outlet or pumped to a storage tank. The condenser is equipped with a safety valve and level control, and operates at a pressure of 0.1-0.3 MPa. The device is installed at the end of the steam path and works with a pump to deliver hot water for heating or power generation. This condenser structure is scale-resistant and easy to clean; those skilled in the art can select a standard model and connect it to the system according to the steam volume.

[0049] In some embodiments, the method is applicable to the production of silicon-manganese alloys with a silicon content of 17-23 wt% and a manganese content of 62-68 wt%, wherein the silicon-manganese alloys are produced in the form of ingots with a weight of 500-1500 kg and a block shape.

[0050] When smelted in a fully enclosed submerged arc furnace, silicon-manganese alloys within this composition range exhibit suitable fluidity and solidification characteristics, making them suitable for casting using this method. The ingot weight is controlled between 500-1500 kg, and the single-batch output of the submerged arc furnace is sufficient for casting, while also facilitating mold design and subsequent crushing. The mold cavity is typically designed as rectangular or cylindrical, with corresponding volume adjustments to ensure that the cast ingot is a regular block shape with a smooth surface and dense interior.

[0051] In actual production, the staged cooling parameters and heat recovery method of this embodiment can be directly applied to ingots of this specification. After casting, the ingot initially solidifies in the mold and undergoes gradual air cooling, intermittent water cooling, and natural cooling. The cooling process is stable, and the heat recovery efficiency is high. The ingot ultimately forms a block product weighing 500-1500 kg, which is convenient for transportation and steelmaking.

[0052] Specifically, in this embodiment, the submerged arc furnace used can be a 36000KVA fully enclosed submerged arc furnace. When smelting silicon-manganese alloys of this composition range in a 36000KVA fully enclosed submerged arc furnace, the single-batch output is typically around 10-20 tons. The ingot weight is controlled between 500-1500 kg, and 15 tons of output can be used to cast 10-30 ingots, resulting in high casting efficiency. Furthermore, the block shape facilitates subsequent crushing and steelmaking, conforming to industrial production practices.

[0053] The staged cooling and heat recovery process of this ingot specification operates smoothly, with strong adaptability to cooling parameters and stable heat recovery effect. Those skilled in the art can directly plan the number of molds and casting cycle based on the output of the submerged arc furnace, achieving efficient and continuous production.

[0054] The silicon-manganese alloy casting method based on gradual air cooling heat recovery provided in this embodiment is an improvement upon existing silicon-manganese alloy casting cooling processes. It achieves precise adjustment of the cooling rate from high temperature to room temperature by combining three-stage gradual wind speed control with intermittent water cooling. This three-stage low-wind-speed gradual cooling method is not a simple extension of existing air convection cooling, but is specifically designed to address the tendency of silicon-manganese alloys to segregate at high temperatures. The wind speed gradually decreases from high to low, combined with stage duration control, resulting in a uniform temperature gradient distribution and significantly reducing silicon segregation and internal voids. This design overcomes the limitations of traditional constant-speed air cooling or single water cooling, providing a complete transition from forced gradual cooling at high temperatures to intermittent cooling at medium temperatures and then to natural final cooling, which helps improve the uniformity of the ingot's internal structure.

[0055] Furthermore, this embodiment tightly integrates the cooling process with heat recovery, employing a dual-path recovery method to process hot air and steam separately. The hot air generated by gradual air cooling is directly used to preheat smelting raw materials via a heat exchanger, while the steam generated by intermittent water cooling is converted into usable thermal energy through a steam recovery device. This dual-path recovery is not a conventional application of existing waste heat treatment; rather, it utilizes the characteristics of different airflows during the cooling stage for targeted collection and conversion, forming a synergistic effect between cooling control and energy circulation, thereby reducing overall energy consumption.

[0056] The silicon-manganese alloy casting method described in this embodiment achieves the integration of rare earth refining in smelting, vibration assistance in the casting process, and staged cooling and heat recovery. The combined effect improves the quality and production efficiency of silicon-manganese alloy ingots and has strong practicality.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 application.

Claims

1. A method for casting silicon-manganese alloy based on gradual air cooling and heat recovery, characterized in that, Includes the following steps: Smelting ferrosilicon manganese alloy liquid: Manganese ore, silica and reducing agent are smelted in a fully enclosed submerged arc furnace, while rare earth elements are added as refining agents. The rare earth element content is 0.01-0.1wt%, and a ferrosilicon manganese alloy liquid with a temperature of 1500-1600℃ is obtained. Casting: The molten alloy is poured into a mold preheated to 800-900℃ to form an ingot. Vibration is used to assist in the pouring process. Staged cooling: After the molten alloy is completely poured into the mold and initially solidifies, it is first subjected to gradual air cooling until the surface temperature of the alloy drops to 1000-1100℃, followed by intermittent water cooling, and then natural cooling to room temperature; the gradual air cooling adopts a three-stage gradual decrease in wind speed and controls the duration of each stage of the gradual air cooling, and the wind speed in each stage of the gradual air cooling does not exceed 5m / s; the intermittent water cooling adopts a spray method, and the water flow rate is controlled at 10-20L / min; Heat recovery: During the phased cooling process, a dual-path recovery method is adopted to collect hot air and steam respectively. In the gradual air cooling process, hot air is collected, and the heat is recovered through a heat exchanger and used to preheat the smelting raw materials. At the same time, steam is collected during the intermittent water cooling process and converted into hot water or steam energy through a steam recovery device for plant heating or auxiliary power generation.

2. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1, characterized in that, Gradual air cooling is achieved by using an adjustable speed fan in conjunction with an air supply duct to connect multiple air nozzles arranged around the molded ingot to cool it. Each air nozzle is evenly distributed around the lower side of the mold. The first stage of gradual air cooling has an air velocity of 4-5 m / s for 10-15 min; the second stage has an air velocity of 2.5-3 m / s for 20-25 min; and the third stage has an air velocity of 1.5-2 m / s for 15-20 min. If the alloy surface temperature does not drop to 1000-1100℃ after the third stage, the air velocity is reduced to below 1 m / s until the temperature reaches the target and then air cooling is stopped.

3. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 2, characterized in that, The number of air blowers is at least 6, and each air blower is evenly distributed around the molded ingot and blows air onto the molded ingot in an oblique upward manner. All air blowers are connected to the air duct connected to the adjustable speed fan.

4. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 2 or 3, characterized in that, Hot air and steam are collected using a gas collection hood that is installed above the molded ingot. The bottom of the gas collection hood has a collection inlet pointing downwards towards the molded ingot. The gas collection hood is connected to two independently arranged branch pipes. One branch pipe is connected to a heat exchanger. During the gradual air cooling stage, hot air enters the gas collection hood through the collection inlet and then enters the branch pipe through a control valve and is guided to the heat exchanger for heat recovery. The other branch pipe is connected to a steam recovery device. During the intermittent water cooling stage, steam enters the gas collection hood through the collection inlet and then enters the branch pipe through a control valve and is guided to the steam recovery device for conversion and utilization.

5. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1, characterized in that, The intermittent water-cooled spray method involves spraying for 5-10 seconds with an interval of 10-15 seconds, for a total of 3-5 cycles.

6. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1 or 5, characterized in that, Intermittent water cooling uses atomizing nozzles for spraying, and the water mist particle size is controlled to be between 50-200μm through the atomizing nozzles.

7. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 6, characterized in that, There are at least 6 atomizing nozzles, which are evenly distributed above the molded ingot and spray the molded ingot intermittently in a downward spraying manner.

8. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1, characterized in that, Vibration-assisted casting is achieved by an electromagnetic vibration device installed at the bottom of the mold, with a vibration frequency of 50-100Hz and a vibration amplitude controlled between 0.5-2mm.

9. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1, characterized in that, The heat exchanger used is a plate heat exchanger, and the steam recovery device used is a shell and tube condenser.

10. The silicon-manganese alloy casting method based on gradual air cooling heat recovery according to claim 1, characterized in that, The method is applicable to the production of silicon-manganese alloys with a silicon content of 17-23 wt% and a manganese content of 62-68 wt%. The silicon-manganese alloys are produced in the form of ingots, with an ingot weight of 500-1500 kg and a block shape.

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