Method for recycling sulfur and producing silicon-manganese alloy by using electrolytic manganese sulfide slag

Abstract

The invention discloses a method for producing a silicon-manganese alloy by using electrolytic manganese sulfide slag. The method comprises the following steps: mixing the sulfide slag with coke or fine coal in proportion, calcining at high temperature, gradually heating in the process to remove crystal water, and carrying out decomposition, oxidation and reduction reactions. Sulfur dioxide gas generated in the calcining process is collected and converted into industrial sulfuric acid. And the calcined manganese-rich slag is used for producing the silicon-manganese alloy. The method has the beneficial effects that the valuable elements in the vulcanized slag are efficiently recycled, the environmental pollution is reduced, the economic benefit is improved, the sustainable development is promoted, the treatment efficiency is improved, the aims of comprehensive utilization and environmental protection of the vulcanized slag are achieved, and an effective solution is provided for industrial production.

Description

Technical Field

[0001] The present invention relates to the field of solid waste treatment, and in particular to a method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag. Background Art

[0002] During the purification process of electrolytic manganese metal (EMM) liquid production, sulfiding agents such as ammonium sulfide and SDD are typically used to further purify the neutralized and iron-removed solution to remove impurities, particularly heavy metals such as copper, cobalt, and nickel. These sulfiding agents react with the metal ions in the solution to form a precipitate, thereby removing impurities. The solid waste generated during this process is called sulfided slag, whose main components include manganese sulfide, manganese sulfate, copper sulfide, cobalt sulfide, and nickel sulfide.

[0003] The production of sulfide slag not only wastes manganese resources but also causes serious environmental pollution. Traditional treatment methods focus on ensuring corrosion and seepage control during sulfide slag storage and centrally storing it. However, this approach fails to effectively address the sulfide slag disposal problem, resulting in significant sulfide slag accumulation, significant space occupation, and the resulting environmental problems that are difficult to manage.

[0004] Sulfide slag contains high levels of sulfur and manganese. If it can be effectively recycled, it will not only create significant economic benefits but also reduce the environmental pollution caused by waste slag storage. Through reasonable resource recovery, these valuable components can be converted into useful industrial products, achieving the dual benefits of environmental protection and resource reuse.

[0005] The main defects of existing sulfide slag treatment technology can be summarized as follows: Environmental pollution and resource waste. Sulfide slag, an unavoidable industrial solid waste generated by the hydrometallurgical industry, is a serious problem. Its long-term storage not only seriously pollutes the environment, erodes soil and water resources, but also occupies a large amount of land resources. Due to the lack of effective treatment technology, the storage of sulfide slag is a serious problem, resulting in a significant waste of resources and environmental degradation.

[0006] Despite the large amount of sulfide slag produced, the industry currently lacks a mature treatment technology solution. Existing treatment methods mostly focus on storage and protection, failing to effectively address the recycling and utilization of sulfide slag, becoming a bottleneck restricting the development of the entire industry.

[0007] Inadequate resource utilization. Sulfide slag contains many recyclable elements, such as manganese, copper, cobalt, and nickel. Long-term storage not only wastes these valuable resources but also violates the concept of sustainable development. Effective resource recovery and utilization can significantly improve raw material utilization efficiency, reduce resource consumption, and reduce environmental impact.

[0008] In summary, in order to deal with the problem of sulfide slag, it is necessary to develop more effective and environmentally friendly technical solutions to solve problems such as resource waste and environmental pollution, and at the same time realize the resource utilization of sulfide slag, which is in line with the strategic goal of sustainable development. Summary of the Invention

[0009] The object of the present invention is to provide a method for recovering sulfur and producing silicon-manganese alloy by using electrolytic manganese sulfide slag.

[0010] The present invention is achieved through the following technical solutions: The method of using electrolytic manganese sulfide slag to recover sulfur and produce silicon-manganese alloy comprises the following steps: Raw material preparation involves selecting and preparing electrolytic manganese sulfide slag as the main raw material; coke or fine coal as the reducing agent and combustion aid. Electrolytic manganese sulfide slag is a waste material containing a high concentration of manganese, primarily composed of manganese sulfides, and has the potential to recover manganese. The choice of coke or fine coal as the reducing agent and combustion aid is crucial. Coke has a high carbon content and good reducing properties, while fine coal provides a sufficient reducing atmosphere and heat.

[0011] Dehydration: Dry and preheat the sulfide slag at 40°C-60°C to remove any external moisture. Dry and preheat the coke or fine coal at 40°C-60°C to remove any external moisture. Drying and preheating the sulfide slag at 40°C-60°C effectively removes any external moisture from the sulfide slag, reducing its moisture content and preventing evaporation during high-temperature calcination, which could cause the material to expand or explode. The coke or fine coal should also be dried at the same temperature to ensure it contains no free moisture and optimize its reducing properties during calcination. This dehydration step aims to improve material stability and reaction efficiency.

[0012] During the pulverization process, the dried sulfide slag is ground to 80-120 mesh; the dried coke or fine coal is ground to 80-120 mesh; and the dried sulfide slag and coke or fine coal are ground to 80-120 mesh to increase their specific surface area. This process improves the reactivity of the materials during the calcination process, allowing them to participate in the chemical reaction more evenly. The pulverized materials can be better mixed with other raw materials, ensuring uniform blending and improving the reaction effect.

[0013] The materials are blended uniformly at a ratio of 90-97 parts sulfide slag to 10-3 parts coke or fine coal to obtain a mixture. This process requires the use of mixing equipment, such as a vertical mixer or twin-screw mixer, to ensure uniform distribution of the components. This uniform blending helps ensure a balanced reaction during high-temperature calcination, preventing local overheating and incomplete reaction.

[0014] High temperature calcination: The evenly mixed mixture is transported to a rotary kiln for high temperature calcination. The temperature is gradually increased to remove the crystal water of the mixture within 60°C-200°C, and the temperature is continued to be increased to carry out decomposition, oxidation, reduction and redox reactions; By-product treatment: sulfur dioxide gas produced during the calcination process is used to prepare industrial sulfuric acid; The main product is collected, and the solid manganese-rich slag after calcination is collected for the production of silicon-manganese alloy.

[0015] Furthermore, the high-temperature calcination comprises the following steps: The uniformly mixed material is sent to the rotary kiln for preliminary heating for about 30 minutes to 1 hour, and the temperature is gradually raised to 105°C to remove free water in the material; Continue to gradually increase the temperature, and use 2 to 3 hours to increase the temperature of the rotary kiln from 105°C to 200°C to ensure that the crystal water in the mixed material is fully removed; After the crystal water is removed, the temperature is raised to a calcination temperature of 600-1200°C over 1-2 hours; then the sulfides and sulfates in the material begin to decompose, generating sulfur dioxide gas and other simple oxides. This process lasts for 2 to 3 hours. Then, under high temperature conditions, the sulfide is further oxidized to generate manganese oxide and manganese dioxide. At the same time, coke or fine coal acts as a reducing agent, providing a reducing atmosphere at high temperature to reduce high-valent manganese to low-valent manganese, generating manganese-rich slag and other by-products.

[0016] Furthermore, the sulfur dioxide gas generated during the calcination process is collected through a gas collection system and used to prepare industrial sulfuric acid, and this process is carried out simultaneously with the high-temperature calcination.

[0017] Furthermore, before the main product is collected, a cooling step is provided, comprising the following steps: Initial cooling: take the calcined high-temperature manganese-rich slag out of the rotary kiln and transfer it to a cooling device or cooling area. Control the cooling rate within 10°C / minute and cool the manganese-rich slag to 400°C-600°C. Natural cooling: take the manganese-rich slag out of the cooling device or cooling area and place it in the air for natural cooling until the temperature drops to 200°C; Forced cooling: Use air cooling to force cool the manganese-rich slag to further reduce the temperature to room temperature; the wind speed is maintained at 2 to 3 meters per second to ensure uniform cooling; Furthermore, after collecting the solid manganese-rich slag after calcination and before using it to produce silicon-manganese alloy, the following post-processing steps are included: Crushing and screening: Use a crusher to break large pieces of manganese-rich slag into small pieces or powder, and use a screening device to separate unqualified particles to ensure uniform product particle size; Magnetic separation and impurity removal: Magnetic separation is carried out to remove ferromagnetic impurities. The iron-containing impurities are separated by magnetic separation equipment to ensure the purity of manganese content in manganese-rich slag; Chemical analysis: chemical composition analysis is performed on the manganese-rich slag after crushing and magnetic separation to ensure that the manganese content and impurity content meet the requirements for silicon-manganese alloy production; Storage and transportation: The treated manganese-rich slag should be stored in dry, sealed containers and prepared for transportation to the silicon-manganese alloy production end. During storage and transportation, care should be taken to avoid secondary contamination of the manganese-rich slag to ensure its purity and quality.

[0018] Furthermore, during the cooling step, the temperature of the manganese-rich slag is monitored in real time by a temperature monitoring device; the temperature monitoring device includes a temperature sensor, a thermocouple or an infrared thermometer, which monitors the entire process of the temperature dropping from the kiln temperature to the room temperature.

[0019] The beneficial effects of the present invention are: Efficient Resource Recovery: Valuable metal elements such as manganese, copper, cobalt, and nickel are effectively recovered from the sulfide slag through high-temperature calcination. During the calcination process, sulfides are converted into usable products such as manganese oxide, significantly increasing the manganese content in the sulfide slag, thereby avoiding resource waste and improving resource utilization efficiency.

[0020] Reduced environmental pollution: By collecting sulfur dioxide gas from sulfide slag and converting it into industrial sulfuric acid, sulfur dioxide emissions are effectively reduced, minimizing environmental pollution. The sulfide slag treatment process not only mitigates the negative impact of waste slag accumulation on the environment, but also reduces the overall environmental burden through the recovery of by-products.

[0021] Improved Economic Efficiency: By processing sulfide slag into manganese-rich slag, which can then be used to produce silico-manganese alloy, waste is recycled. The resulting manganese-rich slag, with its high manganese content, serves as a high-quality raw material for silico-manganese alloy, improving the economic efficiency of alloy production. Recycling sulfide slag not only reduces processing costs but also creates additional economic value.

[0022] Promotes sustainable development: This meets the sustainable development requirements of industrial production resource recovery and environmental protection. By effectively treating sulfide slag, it not only reduces the burden of industrial waste on the environment, but also promotes the recycling of resources and promotes the development of green production technology.

[0023] Improved processing efficiency: In response to the complex composition of sulfide slag, a gradual heating process and high-temperature calcination are employed to ensure that all components in the sulfide slag are fully reacted and converted. This highly efficient treatment method not only increases the resource recovery rate of sulfide slag, but also optimizes the production process and improves overall processing efficiency.

[0024] In summary, the present invention achieves the comprehensive utilization and environmental protection goals of sulfide slag by efficiently recovering valuable elements in sulfide slag, reducing environmental pollution, improving economic benefits, promoting sustainable development and improving treatment efficiency, and provides an effective solution for industrial production. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments: Example: Raw material preparation: Select and prepare electrolytic manganese sulfide slag as the main raw material; select and prepare coke or fine coal as the reducing agent and combustion aid; select and prepare electrolytic manganese sulfide slag as the main raw material. Electrolytic manganese sulfide slag is a waste material containing high concentrations of manganese, mainly composed of manganese sulfides, and has the potential to recover manganese. The choice of coke or fine coal as the reducing agent and combustion aid is crucial. Coke has a high carbon content and good reducing properties, while fine coal can provide a sufficient reducing atmosphere and heat.

[0026] Dehydration: Dry and preheat the sulfide slag at 40°C-60°C to remove any external moisture. Dry and preheat the coke or fine coal at 40°C-60°C to remove any external moisture. Drying and preheating the sulfide slag at 40°C-60°C effectively removes any external moisture from the sulfide slag, reducing its moisture content and preventing evaporation during high-temperature calcination, which could cause the material to expand or explode. The coke or fine coal should also be dried at the same temperature to ensure it contains no free moisture and optimize its reducing properties during calcination. This dehydration step aims to improve material stability and reaction efficiency.

[0027] During the pulverization process, the dried sulfide slag is ground to 80-120 mesh; the dried coke or fine coal is ground to 80-120 mesh; and the dried sulfide slag and coke or fine coal are ground to 80-120 mesh to increase their specific surface area. This process improves the reactivity of the materials during the calcination process, allowing them to participate in the chemical reaction more evenly. The pulverized materials can be better mixed with other raw materials, ensuring uniform blending and improving the reaction effect.

[0028] The materials are blended uniformly at a ratio of 90-97 parts sulfide slag to 10-3 parts coke or fine coal to obtain a mixture. This process requires the use of mixing equipment, such as a vertical mixer or twin-screw mixer, to ensure uniform distribution of the components. This uniform blending helps ensure a balanced reaction during high-temperature calcination, preventing local overheating and incomplete reaction.

[0029] High-temperature calcination: The uniformly blended mixture is fed into a rotary kiln for initial heating. This process lasts approximately 30 minutes to 1 hour, with the temperature gradually raised to 105°C to remove free water from the material. To avoid rapid evaporation of surface moisture and difficulty in removing internal water due to excessive heating, uniform heating should be maintained to ensure even heating of the material.

[0030] Then, continue to slowly increase the temperature to a range of 105°C to 200°C to ensure that the crystal water in the mixture is fully removed. This process takes about 2 to 3 hours. Uneven temperature may cause some materials to not be completely dehydrated, so it is necessary to continue to slowly increase the temperature to ensure that the internal crystal water is fully removed.

[0031] After the crystal water is removed, the temperature is raised to the preset high-temperature calcination temperature (600°C to 1200°C). This process takes about 1 to 2 hours. Rapid heating may lead to incomplete decomposition of the material or a sudden reaction. Therefore, the temperature should be raised in stages, with each stage maintained for a period of time to ensure sufficient decomposition of the material.

[0032] Once the calcination temperature is reached, the sulfides and sulfates in the material begin to decompose, producing sulfur dioxide gas and other simple oxides. This process takes approximately 2 to 3 hours. If the temperature is too low, decomposition may be incomplete, while if it is too high, excessive by-products may result. Therefore, the high temperature must be maintained to ensure complete decomposition of the sulfides and sulfates.

[0033] Next, under high temperature conditions, the sulfides are further oxidized to form manganese oxide and manganese dioxide. Insufficient oxygen supply may lead to incomplete oxidation, so it is necessary to ensure an adequate oxygen supply to promote the oxidation of the sulfides.

[0034] During the high-temperature calcination process, coke or fine coal acts as a reducing agent and combustion aid, providing a reducing atmosphere at high temperatures to reduce the high-valent manganese to low-valent manganese. Insufficient reducing agent may result in incomplete reduction, while excessive reducing agent may cause side reactions. Therefore, the amount of reducing agent must be controlled to ensure that the high-valent manganese is reduced to low-valent manganese.

[0035] During this process, the various components in the mixture undergo complex redox reactions, producing manganese-rich slag and other byproducts. Incomplete reactions can result in substandard product quality, so maintaining high temperatures and ensuring sufficient reaction time are essential to ensure that the various components in the mixture react fully.

[0036] The sulfur dioxide gas produced during the calcination process is efficiently collected by a gas collection system and used to produce industrial sulfuric acid. The gas collection system must ensure normal operation to prevent the sulfur dioxide gas from escaping. This process is carried out simultaneously with the high-temperature calcination.

[0037] The sulfur dioxide gas generated during the calcination process is effectively captured and treated by a gas collection system. The core components of the gas collection system include gas piping, gas filtration, gas compression equipment, and gas storage tanks. These components work together to ensure efficient collection and subsequent treatment of sulfur dioxide gas.

[0038] Gas pipelines are responsible for directing sulfur dioxide gas generated during the calcination process from the rotary kiln to the gas collection system. The pipelines must be designed to be resistant to high temperatures and corrosion to accommodate the flow of high-temperature and acidic gases. Flow regulators are installed within the pipelines to control the gas flow rate, ensuring a stable flow and preventing gas accumulation or reverse flow.

[0039] Gas filtration equipment is used to remove solid particles and impurities from gases. Commonly used filtration devices include bag filters or cyclone separators, which effectively capture particulate matter in the gas and prevent it from damaging downstream equipment. The filtered gas then enters the gas compression equipment, which compresses it to an appropriate pressure for storage and transportation.

[0040] Gas storage tanks are used to store compressed sulfur dioxide gas for subsequent use or processing. Storage tanks must be designed to meet safety standards, have sufficient pressure resistance, and be equipped with necessary monitoring and safety devices to prevent gas leaks or abnormal pressures. Gas in the storage tanks can be transported to sulfuric acid production facilities as needed for the production of industrial sulfuric acid.

[0041] The entire gas collection system operates in tandem with the high-temperature calcination process, ensuring the efficient collection and utilization of sulfur dioxide gas through precise control and monitoring. At the same time, the gas collection system requires regular maintenance and overhaul to ensure stable operation and long-term reliability.

[0042] Finally, after calcination, the hot manganese-rich slag is cooled to room temperature, which takes about 1 to 2 hours. Cooling too quickly may cause the manganese-rich slag to crack or deteriorate in quality, so the cooling rate must be controlled to ensure that the manganese-rich slag is completely collected. The specific steps include: After calcining, the high-temperature, manganese-rich slag is removed from the rotary kiln and transferred to a cooling device or cooling area. This stage requires gradual cooling to prevent thermal stress caused by rapid cooling, which could lead to cracking or degradation of the manganese-rich slag. The initial cooling process should last approximately one hour, with the temperature gradually decreasing from the highest calcination temperature (approximately 1200°C) to 400-600°C. The cooling device should be able to maintain a uniform temperature drop rate, controlling the cooling rate to within 10°C / minute to ensure uniform cooling of the material.

[0043] Next, the manganese-rich slag is removed from the cooling device and placed in the air for natural cooling. This natural cooling process takes approximately 1 to 2 hours, further reducing the material temperature to 200°C. This stage relies on the natural environment for cooling, and the cooling area should be well ventilated to avoid local overheating that may affect the quality of the manganese-rich slag.

[0044] To expedite the cooling process, forced air cooling is used to cool the manganese-rich slag. This process lasts approximately 30 minutes to an hour, reducing the temperature from 200°C to room temperature. Air cooling requires the use of a fan or air flow cooling device. During forced cooling, the wind speed must be carefully controlled, maintaining a constant 2 to 3 meters per second to prevent excessive cooling that could affect product quality.

[0045] Throughout the cooling process, the temperature of the manganese-rich slag must be monitored in real time to ensure it remains within the preset range. Temperature monitoring equipment, including temperature sensors, thermocouples, or infrared thermometers, monitors the entire process from 1200°C to room temperature. The temperature curve is recorded to ensure the cooling rate does not exceed 10°C / minute to prevent drastic temperature fluctuations that could adversely affect product quality.

[0046] Among them, during the cooling process, after the calcined high-temperature manganese-rich slag is taken out of the rotary kiln, it needs to be transferred to a cooling device or cooling area. The cooling device is usually composed of multiple key components, including a cooling trough or cooling car, a cooling system, a temperature sensor and control system, and a possible exhaust device. The cooling trough or cooling car serves as a container to carry the high-temperature manganese-rich slag, taking into account high temperature tolerance and good thermal conductivity to ensure uniform cooling of the material. The bottom and side wall structures of the cooling device help to conduct heat to the material and avoid thermal stress caused by rapid temperature changes.

[0047] The cooling system consists of air cooling and / or water cooling. Air cooling systems include adjustable fans, while water cooling systems utilize sprinklers or water flow devices. These systems are connected to cooling tanks or cooling carts via pipes, air ducts, or sprinklers, providing the necessary cooling medium to reduce the temperature of the manganese-rich slag. Air cooling systems adjust fan speed, while water cooling systems control water flow to evenly distribute the cooling medium across the material surface, thereby controlling the cooling rate.

[0048] During the cooling process, temperature sensors are installed in the cooling tank or cooling cart to monitor the temperature of the manganese-rich slag in real time. These sensors are connected to a control system, which adjusts the air or water cooling system based on the set cooling rate to ensure the cooling process meets the desired requirements. Exhaust systems (such as ventilation ducts and fans), if installed, are used to remove gases or vapors generated during the cooling process to prevent gas accumulation that could adversely affect cooling efficiency and operational safety.

[0049] The entire cooling area must be designed to coordinate with the cooling trough or cooling cart to ensure environmental control during the cooling process. The cooling area may include walls and flooring to protect the cooling unit and the surrounding environment. Through the proper layout and connection of these components, the cooling unit can effectively control the temperature drop of the manganese-rich slag, preventing material breakage or quality degradation caused by rapid cooling, and ensuring the stability and reliability of the final product.

[0050] Finally, after the manganese-rich slag has cooled to room temperature, the following processing steps are required to ensure its quality and make it suitable for the production of silicon-manganese alloys: Crushing and screening: After cooling, the manganese-rich slag may form large lumps of material, which need to be crushed. Use a crusher to break the large manganese-rich slag into small pieces or powder of appropriate particle size. Use a screening device to screen and separate unqualified particles to ensure uniform product particle size.

[0051] Magnetic separation to remove impurities: In order to improve the purity of manganese-rich slag, magnetic separation can be carried out to remove ferromagnetic impurities therein. The iron-containing impurities can be separated by a magnetic separation device to ensure the purity of the manganese content in the manganese-rich slag.

[0052] Chemical analysis: The chemical composition analysis of the manganese-rich slag after crushing and magnetic separation is carried out to ensure that the manganese content and impurity content meet the requirements of silicon-manganese alloy production. The main components and impurity content of the manganese-rich slag are detected using chemical analysis methods to ensure its stable quality.

[0053] Storage and transportation: The treated manganese-rich slag must be properly stored to prevent moisture and contamination. It should be stored in dry, sealed containers until it is shipped to the silicon-manganese alloy production site. During storage and transportation, care should be taken to avoid secondary contamination of the manganese-rich slag to ensure its purity and quality.

[0054] Through the above processing steps, the cooled and treated manganese-rich slag will meet the requirements of silicon-manganese alloy production and provide high-quality raw materials for the next alloy production.

[0055] In summary, through the above detailed steps, the electrolytic manganese sulfide slag is effectively controlled in each link of the silicon-manganese alloy production process, and finally high-quality manganese-rich slag and other by-products are obtained.

[0056] After testing, the manganese-rich slag produced by the method of the present invention has the following properties and characteristics: Appearance and Physical Properties: The manganese-rich slag is a black or dark gray solid, primarily in granular or powder form. Due to high-temperature calcination and cooling, the slag has a uniform surface and a certain gloss. After crushing and screening, the slag has a uniform particle size distribution, making it suitable for further industrial applications.

[0057] Chemical Composition: Manganese-rich slag is primarily composed of high levels of manganese oxides, particularly manganese oxide and manganese dioxide. These manganese oxides are formed during high-temperature calcination through the decomposition and oxidation of sulfides and sulfates. Manganese-rich slag also contains small amounts of silica and other minerals, such as bauxite and calcium minerals, derived from impurities in the sulfide slag.

[0058] Physical and Chemical Properties: Manganese-rich slag has a high density and hardness, which imparts excellent wear resistance. Chemically, it is relatively stable and does not readily react with moisture or airborne oxidants. Due to its high concentration of manganese oxides, it exhibits strong chemical stability at high temperatures, making it suitable for use in the smelting of silicon-manganese alloys.

[0059] Uses and Applications: Manganese-rich slag is primarily used to produce silico-manganese alloys. During the smelting process, manganese-rich slag serves as a crucial manganese source. Further melting and processing effectively converts the manganese present in the silico-manganese alloy. Due to its high manganese content, manganese-rich slag significantly enhances the quality and performance of the alloy. Furthermore, the silica and other minerals in the slag can provide additional functionality in certain applications.

[0060] In summary, the manganese-rich slag produced by the method of the present invention has excellent physical and chemical properties, is suitable for the production of silicon-manganese alloy, and has high market application value and environmental friendliness.

[0061] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag, characterized in that: The following steps are involved: Raw material preparation: selecting and preparing electrolytic manganese sulfide slag as the main raw material; selecting and preparing coke or fine coal as a reducing agent and combustion aid; Dehydration treatment: drying and preheating the sulfide slag at 40℃-60℃ to remove external water; drying and preheating the coke or fine coal at 40℃-60℃ to remove external water; Crushing treatment: grinding the dried sulfide slag to 80-120 mesh; grinding the dried coke or fine coal powder to 80-120 mesh; The materials are mixed evenly in a ratio of 90-97 parts of sulfide slag and 10-3 parts of coke or fine coal to obtain a mixed material; High temperature calcination: transport the uniformly mixed material to a rotary kiln for high temperature calcination, gradually increase the temperature to remove the crystal water of the mixed material within 60℃-200℃, and continue to increase the temperature for calcination to perform decomposition, oxidation, reduction and redox reactions; By-product treatment: sulfur dioxide gas produced during calcination is used to prepare industrial sulfuric acid; The main product is collected, and the solid manganese-rich slag after calcination is collected for the production of silicon-manganese alloy.

2. The method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag as claimed in claim 1, characterized in that: The high temperature calcination comprises the following steps: The uniformly mixed material is sent to a rotary kiln for preliminary heating for about 30 minutes to 1 hour, and the temperature is gradually raised to 105°C to remove free water from the material; Continue to gradually increase the temperature, and use 2 to 3 hours to raise the temperature of the rotary kiln from 105°C to 200°C to ensure that the crystal water in the mixed material is fully removed; After the crystal water is removed, the temperature is raised to a calcination temperature of 600-1200°C in 1-2 hours; then the sulfides and sulfates in the material begin to decompose, generating sulfur dioxide gas and other simple oxides, and this process lasts for 2 to 3 hours; Then, under high temperature conditions, the sulfide is further oxidized to generate manganese oxide and manganese dioxide. At the same time, coke or fine coal acts as a reducing agent to provide a reducing atmosphere at high temperature to reduce high-valent manganese to low-valent manganese, generating manganese-rich slag and other by-products.

3. The method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag as claimed in claim 1, characterized in that: The sulfur dioxide gas generated during the calcination process is collected through a gas collection system and used to prepare industrial sulfuric acid, and this process is carried out simultaneously with the high-temperature calcination.

4. The method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag as claimed in claim 1, characterized in that: Before the main product is collected, a cooling step is provided, comprising the following steps: Preliminary cooling: take out the calcined high-temperature manganese-rich slag from the rotary kiln and transfer it to a cooling device or cooling area. Control the cooling rate within 10°C / minute and cool the manganese-rich slag to 400°C-600°C. Natural cooling: take the manganese-rich slag out of the cooling device or cooling area and place it in the air for natural cooling until the temperature drops to 200°C; Forced cooling: Use air cooling to force cool the manganese-rich slag to further reduce the temperature to room temperature; the wind speed is maintained at 2 to 3 meters per second to ensure uniform cooling.

5. The method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag as claimed in claim 1 or 2, characterized in that: After the solid manganese-rich slag after calcination is collected, before it is used to produce silicon-manganese alloy, the following post-processing steps are included: Crushing and screening: Use a crusher to break large pieces of manganese-rich slag into small pieces or powder, and use a screening device to screen and separate unqualified particles to ensure uniform product particle size; Magnetic separation and impurity removal: Magnetic separation is carried out to remove ferromagnetic impurities. The iron-containing impurities are separated by magnetic separation equipment to ensure the purity of manganese content in manganese-rich slag; Chemical analysis: chemical composition analysis is performed on the manganese-rich slag after crushing and magnetic separation to ensure that the manganese content and impurity content meet the requirements for silicon-manganese alloy production; Storage and transportation: Store the treated manganese-rich slag in a dry, sealed container, ready for transportation to the silicon-manganese alloy production end; During storage and transportation, care should be taken to avoid secondary contamination of manganese-rich slag to ensure its purity and quality.

6. The method for recovering sulfur and producing silicon-manganese alloy using electrolytic manganese sulfide slag as claimed in claim 4, characterized in that: In the cooling step, the temperature of the manganese-rich slag is monitored in real time by a temperature monitoring device; the temperature monitoring device includes a temperature sensor, a thermocouple or an infrared thermometer, which monitors the entire process of the temperature dropping from the kiln temperature to the room temperature.