Method for preparing brown fused alumina mullite refractory and ferrosilicon alloy from low-quality bauxite ore

Abstract

The invention provides a method for preparing brown fused alumina mullite refractory and ferrosilicon alloy from low-quality bauxite ore, and belongs to the technical field of metallurgy. According to the method provided by the invention, impurity elements such as iron, titanium and silicon in the low-quality bauxite can be effectively separated, enrichment and purification of the bauxite are realized, high-value utilization of the low-quality bauxite which is originally difficult to utilize is realized, and the utilization rate of bauxite resources is increased; by accurately controlling technological parameters in the smelting process, good crystallization and growth of a corundum phase and a mullite phase are promoted, the produced brown fused alumina mullite refractory product is stable in quality and excellent in performance, and meanwhile, the ferrosilicon alloy is stable in component and meets related quality standards; by controlling smelting conditions and optimizing the process, corrosion and damage to submerged arc furnace equipment are reduced, damage to furnace linings, electrodes and other components due to excessive low-melting-point substances in slag and abnormal reaction is avoided, the service life of the equipment is prolonged, and the maintenance cost of the equipment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a method for preparing brown corundum mullite refractory materials and ferrosilicon alloys by utilizing low-quality bauxite ore. Background Art

[0002] Low-quality bauxite ore contains approximately 50% alumina and contains high levels of Fe2O3, TiO2, and SiO2, with Fe2O3 reaching as high as 15-20%. The presence of these impurities severely restricts the utilization of low-quality bauxite. Traditional processes struggle to effectively separate elements such as iron, titanium, and silicon, hindering the enrichment, purification, and high-value utilization of low-quality bauxite. Existing smelting methods for processing low-quality bauxite suffer from incomplete iron-slag separation, unstable product quality, high energy consumption, and susceptible equipment damage. For example, iron oxides combine with silicon and aluminum oxides to form low-melting-point substances, lowering the melting point of refractory materials and causing chemical corrosion. Furthermore, the existing heating methods and parameter control are irrational, resulting in incomplete furnace reactions, impacting product quality and production efficiency. Therefore, developing a new smelting method is crucial for achieving efficient utilization of low-quality bauxite. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing brown corundum mullite refractory materials and ferrosilicon alloys using low-quality bauxite ore. The brown corundum mullite refractory materials and ferrosilicon alloys obtained by the method provided by the present invention meet the requirements, realize the efficient utilization of low-quality bauxite, reduce the erosion and damage to the submerged arc furnace equipment, and extend the service life of the equipment.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing brown corundum mullite refractory and ferrosilicon alloy by using low-quality bauxite ore, comprising the following steps:

[0006] (1) crushing, granulating and calcining low-quality bauxite ore in sequence to obtain bauxite clinker;

[0007] (2) mixing the bauxite clinker obtained in step (1) with coke to obtain a mixture, and then smelting the mixture and separating the iron slag in sequence to obtain slag and ferrosilicon alloy; the carbon-oxygen ratio of the mixture is 1.5 to 2.0; the smelting temperature is 1800 to 1850° C., and the smelting time is ≥60 min;

[0008] (3) The slag obtained in step (2) is subjected to post-iron removal treatment to obtain brown corundum mullite refractory material.

[0009] Preferably, the particle size of the product after granulation in step (1) is 10 to 30 mm.

[0010] Preferably, the calcination temperature in step (1) is 1000-1200° C., and the calcination time is 3-4 hours.

[0011] Preferably, the particle size of the bauxite clinker in step (1) is 10 to 30 mm.

[0012] Preferably, the carbon-oxygen ratio of the mixture in step (2) is 1.6 to 1.8.

[0013] Preferably, the smelting time in step (2) is 60 to 120 minutes; the smelting is carried out in a special-shaped submerged arc furnace.

[0014] Preferably, when smelting is carried out in a special-shaped submerged arc furnace, the iron slag is separated by first opening the iron outlet to discharge the ferrosilicon, preheating the chute in the special-shaped submerged arc furnace at the same time, and then opening the slag outlet to discharge the slag.

[0015] Preferably, the preheating treatment is carried out by electric heating or hot flue gas preheating; the preheating temperature is 1150-1250°C.

[0016] Preferably, in step (2), the slag is subjected to a heat preservation and slow cooling treatment.

[0017] Preferably, the post-iron removal treatment in step (3) includes crushing, screening and iron removal performed in sequence.

[0018] The present invention provides a method for preparing brown corundum mullite refractory and ferrosilicon alloy by using low-quality bauxite ore, comprising the following steps: (1) crushing, granulating and calcining the low-quality bauxite ore in sequence to obtain bauxite clinker; (2) mixing the bauxite clinker obtained in step (1) with coke to obtain a mixture, and then smelting and separating the iron slag from the mixture in sequence to obtain slag and ferrosilicon alloy; the carbon-oxygen ratio of the mixture is 1.5-2.0; the smelting temperature is 1800-1850°C, and the smelting time is ≥60min; (3) performing iron removal post-treatment on the slag obtained in step (2) to obtain brown corundum mullite refractory. The method provided by the present invention can effectively separate impurity elements such as iron, titanium and silicon from low-quality bauxite, realize the enrichment and purification of bauxite, and make high-value utilization of low-quality bauxite that was originally difficult to utilize, thereby improving the utilization rate of bauxite resources; by precisely controlling the process parameters (temperature, time and carbon-oxygen ratio, etc.) during the smelting process, the good crystallization and growth of the corundum phase and the mullite phase are promoted, and the quality of the brown corundum mullite refractory products produced is stable and the performance is excellent. At the same time, the silicon-iron alloy composition is stable and meets the relevant quality standards; through reasonable raw material processing and smelting process, as well as precise control of the reaction in the furnace, energy waste is reduced and energy consumption in the production process is reduced; by controlling the smelting conditions and optimizing the process, erosion and damage to the submerged arc furnace equipment are reduced, and damage to components such as the furnace lining and electrodes due to excessive low-melting-point substances in the slag and abnormal reactions is avoided, the service life of the equipment is extended, and the equipment maintenance cost is reduced. The results of the examples show that the method provided by the present invention uses low-quality bauxite as raw material to obtain brown corundum mullite refractory material (alumina content ≥ 70%) with corundum and mullite phase contents that meet quality requirements and ferrosilicon alloy with composition and performance that meet requirements. DETAILED DESCRIPTION

[0019] The present invention provides a method for preparing brown corundum mullite refractory and ferrosilicon alloy by using low-quality bauxite ore, comprising the following steps:

[0020] (1) crushing, granulating and calcining low-quality bauxite ore in sequence to obtain bauxite clinker;

[0021] (2) mixing the bauxite clinker obtained in step (1) with coke to obtain a mixture, and then smelting the mixture and separating the iron slag in sequence to obtain slag and ferrosilicon alloy; the carbon-oxygen ratio of the mixture is 1.5 to 2.0; the smelting temperature is 1800 to 1850° C., and the smelting time is ≥60 min;

[0022] (3) The slag obtained in step (2) is subjected to post-iron removal treatment to obtain brown corundum mullite refractory material.

[0023] The invention sequentially crushes, granulates and calcines low-quality bauxite to obtain bauxite clinker.

[0024] The present invention has no particular limitation on the specific source of the low-quality bauxite, and commercially available low-quality bauxite well known to those skilled in the art can be used.

[0025] The present invention has no particular limitation on the specific operations of the crushing and granulation, as long as the particle size of the granulated product meets the requirements. In the present invention, the particle size of the granulated product is preferably 10 to 30 mm, more preferably 15 to 25 mm, and even more preferably 20 mm.

[0026] In the present invention, the calcination temperature is preferably 1000-1200°C, more preferably 1050-1150°C, and even more preferably 1100°C; the calcination time is preferably 3-4 hours; and the calcination is preferably carried out in a shaft kiln or a rotary kiln. The present invention does not particularly limit the specific model of the shaft kiln or rotary kiln; commercially available products familiar to those skilled in the art can be used. The present invention can remove impurities from low-quality bauxite through calcination, thereby improving the quality of the low-quality bauxite.

[0027] In the present invention, after calcination, the calcined product is preferably cooled, crushed, and screened in sequence. The present invention does not specifically limit the cooling method; natural cooling, furnace cooling, or air cooling may be employed to achieve room temperature. The present invention does not specifically limit the specific operations of crushing and screening; they only need to achieve a particle size that meets the requirements for the bauxite clinker.

[0028] In the present invention, the particle size of the bauxite clinker is preferably 10 to 30 mm, more preferably 15 to 25 mm, and even more preferably 20 mm. By controlling the particle size of the bauxite clinker, the present invention facilitates subsequent mixing with coke.

[0029] After obtaining the bauxite clinker, the present invention mixes the bauxite clinker with coke to obtain a mixture, and then sequentially smelts and separates the iron slag to obtain slag and ferrosilicon alloy.

[0030] The present invention does not specifically limit the specific amounts of bauxite clinker and coke used, as long as the mixture's carbon-oxygen ratio meets the requirements. In the present invention, the carbon-oxygen ratio of the mixture is 1.5 to 2.0, preferably 1.6 to 1.8. By controlling the carbon-oxygen ratio of the mixture, the present invention improves charge permeability, optimizes the kinetics of the reduction of various oxides during subsequent smelting, and prevents the sudden drop in slag temperature and crusting caused by the addition of cold coke to the furnace.

[0031] The present invention has no special limitation on the specific operation of mixing the bauxite clinker and coke, as long as the bauxite clinker and coke can be mixed evenly.

[0032] In the present invention, the smelting temperature is 1800-1850°C; the smelting time is ≥ 60 minutes, preferably 60-120 minutes, and more preferably 80-100 minutes; and the smelting is preferably carried out in a special-shaped submerged arc furnace. By controlling the smelting temperature and time, the present invention ensures that the reaction in the furnace is sufficient and stable.

[0033] The present invention has no particular limitation on the speed of adding the mixture during the smelting process, as long as the mixture is prevented from falling into the hot slag and causing splashing and crusting.

[0034] The present invention does not have any special restrictions on the specific operation of the iron slag separation, as long as the slag and ferrosilicon can be separated. In the present invention, when smelting is carried out in a special-shaped ore furnace, the method of separating the iron slag is preferably: first open the iron outlet to discharge the ferrosilicon, and at the same time preheat the chute in the special-shaped ore furnace, then heat the slag to the outflow temperature, and then open the slag outlet to discharge the slag. In the present invention, the preheating method is preferably electric heating or hot flue gas preheating; the preheating temperature is preferably 1150-1250°C, more preferably 1200°C; the outflow temperature is preferably 1400-1500°C, more preferably 1450-1500°C. The present invention can effectively prevent the slag from being rapidly cooled and solidified when flowing out by heating the slag and preheating the chute, so that the slag can be discharged smoothly.

[0035] The present invention preferably performs a heat preservation and slow cooling treatment on the slag; the heat preservation and slow cooling treatment is preferably natural cooling in the ladle. The heat preservation and slow cooling treatment can promote the crystallization and growth of the corundum phase and mullite phase in the slag, thereby facilitating the subsequent separation of iron slag.

[0036] After obtaining the slag, the present invention performs post-treatment on the slag to remove iron, so as to obtain brown corundum mullite refractory material.

[0037] In the present invention, the post-ironing treatment preferably includes crushing, screening, and iron removal performed sequentially. The present invention does not particularly limit the specific operations of crushing, screening, and iron removal; crushing, screening, and iron removal methods familiar to those skilled in the art may be employed. The post-ironing treatment of the present invention can remove residual iron metal, thereby obtaining brown corundum mullite refractory that meets quality requirements.

[0038] The method provided by the present invention can effectively separate impurity elements such as iron, titanium and silicon from low-quality bauxite, achieve the enrichment and purification of bauxite, enable the low-quality bauxite that was originally difficult to utilize to high value, and improve the utilization rate of bauxite resources.

[0039] The present invention promotes the good crystallization and growth of corundum and mullite phases by precisely controlling the process parameters (temperature, time and carbon-oxygen ratio, etc.) during the smelting process and combining the special structural advantages of the special-shaped submerged arc furnace. The brown corundum mullite refractory products produced have stable quality and excellent performance. At the same time, the ferrosilicon alloy composition is stable and meets the relevant quality standards.

[0040] The present invention reduces energy waste and lowers energy consumption in the production process through reasonable raw material processing and smelting technology, as well as precise control of the reaction in the furnace.

[0041] The present invention reduces erosion and damage to submerged arc furnace equipment by controlling smelting conditions and optimizing processes, avoids damage to components such as furnace linings and electrodes caused by excessive low-melting-point substances in the slag and abnormal reactions, extends the service life of the equipment, and reduces equipment maintenance costs.

[0042] During the smelting process, the present invention uses electrical heating or hot flue gas preheating to utilize waste heat and improve energy efficiency. Furthermore, the entire process of the present invention reduces the generation of pollutants such as waste gas and waste residue, thus meeting environmental protection requirements.

[0043] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. 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.

[0044] Example 1

[0045] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0046] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0047] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 1.5 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1800° C. and a smelting time of 60 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1800 to 1850° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a ladle to obtain slag and ferrosilicon alloy;

[0048] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0049] The composition of the brown corundum mullite refractory prepared in Example 1 was tested, and the mass percentage of Al2O3 in the brown corundum mullite refractory reached 72.3%, and the contents of corundum phase and mullite phase met the quality requirements of brown corundum mullite refractory; the composition and performance of ferrosilicon alloy met the quality standards of ferrosilicon alloy.

[0050] Example 2

[0051] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0052] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0053] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 2.0 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1850° C. and a smelting time of 70 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1800 to 1850° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a ladle to obtain slag and ferrosilicon alloy;

[0054] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0055] The composition of the brown corundum mullite refractory prepared in Example 2 was tested, and the mass percentage of Al2O3 in the brown corundum mullite refractory reached 72.3%, and the contents of corundum phase and mullite phase met the quality requirements of brown corundum mullite refractory; the composition and performance of ferrosilicon alloy met the quality standards of ferrosilicon alloy.

[0056] Comparative Example 1

[0057] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0058] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0059] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 1.0 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1850° C. and a smelting time of 70 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1800 to 1850° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a ladle to obtain slag and ferrosilicon alloy;

[0060] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0061] Comparative Example 2

[0062] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0063] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0064] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 3.0 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1850° C. and a smelting time of 70 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1800 to 1850° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a ladle to obtain slag and ferrosilicon alloy;

[0065] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0066] Comparative Example 3

[0067] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0068] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0069] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 2.0 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1600° C. and a smelting time of 70 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1600 to 1650° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a receiving bag to obtain slag and ferrosilicon alloy;

[0070] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0071] Comparative Example 4

[0072] A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore comprises the following steps:

[0073] (1) crushing and granulating low-quality bauxite ore in sequence to obtain low-quality bauxite particles with a particle size of 10 to 30 mm, then calcining the low-quality bauxite particles in a rotary kiln at a calcination temperature of 1100° C. for 4 hours, and finally cooling, crushing and screening in sequence to obtain bauxite clinker with a particle size of 10 to 30 mm;

[0074] (2) the bauxite clinker obtained in the step (1) and the coke are mixed at a carbon-oxygen ratio of 2.0 and then smelted in a special-shaped submerged arc furnace at a smelting temperature of 1800° C. and a smelting time of 40 min. When the mixture is added during the smelting process, the temperature in the furnace is monitored in real time by a temperature sensor so that the smelting temperature is always maintained in the range of 1800 to 1850° C. After the smelting is completed, the iron slag is separated, the iron outlet is opened to discharge the ferrosilicon, and the chute in the special-shaped submerged arc furnace is preheated with hot flue gas until the temperature of the chute is 1200° C., then the slag is heated to 1500° C., and then the slag outlet is opened to discharge the slag through the chute. Finally, the slag is subjected to a heat preservation and slow cooling treatment, and is naturally cooled in a ladle to obtain slag and ferrosilicon alloy;

[0075] (3) The slag obtained in step (2) is crushed, screened and iron removed in sequence to obtain brown corundum mullite refractory material.

[0076] The aluminum oxide content in the brown corundum mullite refractory obtained in Comparative Examples 1 to 4 is ≤65%, and the contents of the corundum phase and the mullite phase do not meet the quality requirements of the brown corundum mullite refractory.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing brown corundum mullite refractory and ferrosilicon alloy using low-quality bauxite ore, comprising the following steps: (1) crushing, granulating and calcining low-quality bauxite ore in sequence to obtain bauxite clinker; (2) mixing the bauxite clinker obtained in step (1) with coke to obtain a mixture, and then smelting the mixture and separating the iron slag in sequence to obtain slag and ferrosilicon alloy; the carbon-oxygen ratio of the mixture is 1.5 to 2.0; the smelting temperature is 1800 to 1850° C., and the smelting time is ≥60 min; (3) The slag obtained in step (2) is subjected to post-iron removal treatment to obtain brown corundum mullite refractory material.

2. The method according to claim 1, characterized in that The particle size of the product after granulation in step (1) is 10 to 30 mm.

3. The method according to claim 1, characterized in that The calcination temperature in step (1) is 1000-1200° C., and the calcination time is 3-4 hours.

4. The method according to claim 1, wherein The particle size of the bauxite clinker in step (1) is 10 to 30 mm.

5. The method according to claim 1, wherein The carbon-oxygen ratio of the mixture in step (2) is 1.6 to 1.

8.

6. The method according to claim 1, characterized in that The smelting time in step (2) is 60 to 120 minutes; the smelting is carried out in a special-shaped submerged arc furnace.

7. The method according to claim 6, characterized in that When smelting is carried out in a special-shaped submerged arc furnace, the iron slag separation method is: first open the iron outlet to discharge the ferrosilicon, preheat the chute in the special-shaped submerged arc furnace at the same time, and then open the slag outlet to discharge the slag.

8. The method according to claim 7, characterized in that The preheating treatment is carried out by electric heating or hot flue gas preheating; the preheating temperature is 1150-1250°C.

9. The method according to claim 1, characterized in that In the step (2), the slag is subjected to a heat preservation and slow cooling treatment.

10. The method according to claim 1, characterized in that The post-iron removal treatment in step (3) includes crushing, screening and iron removal performed in sequence.