A method and device for preparing silicon manganese nitride alloy

Abstract

The present invention provides a method and device for preparing silicon nitride manganese alloy, wherein high-purity nitrogen is continuously introduced into a vertical furnace, and the oxygen in the vertical furnace is completely replaced by nitrogen, and the pressure of the nitrogen in the vertical furnace is maintained to be greater than the atmospheric pressure; according to the target smelting silicon nitride manganese alloy component requirements, electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon are mixed according to the calculated component ratio and then put into the vertical furnace; the mixed material in the vertical furnace is ignited by electric arc ignition, and when the temperature of the reaction zone in the furnace reaches 850°C to 1200°C, a nitriding reaction is performed to obtain silicon nitride manganese alloy powder, and the prepared silicon nitride manganese alloy powder is discharged from the bottom of the vertical furnace body by sedimentation; after the above steps are completed, a self-propagating reaction is performed to obtain silicon nitride manganese alloy. The present application enables the nitrogen content of the generated silicon nitride manganese alloy to be stabilized at a relatively high state.

Description

Technical Field

[0001] The present application relates to a method for preparing an alloy material, and more specifically, to a method for preparing a silicon manganese nitride alloy. Background Art

[0002] As a nitrogen additive, silicon manganese nitride has a high nitrogen content and can play a role in increasing nitrogen in steel, significantly enhancing the Nb precipitation strengthening and grain refinement in steel, promoting and optimizing the precipitation of vanadium, and achieving the effect of increasing nitrogen and reducing vanadium. Silicon nitride alloy has a good prospect for use in the production of high nitrogen alloy steel.

[0003] At present, the preparation methods of silicon manganese nitride alloy mainly include the following methods:

[0004] The patent disclosure document (CN104878239A) discloses a high-temperature self-propagating synthesis method of silicon nitride manganese alloy, which uses 75 ferrosilicon and ferromanganese powder as raw materials, weighs them according to the ingredient calculation, and adds chemical stimulants. The homogenized and mixed powder is loaded into a reaction boat, placed in a high-temperature self-propagating furnace, and after vacuuming, high-purity nitrogen is introduced, and the pressure is controlled at 10MPa. With the help of external thermal stimulation, ignition and induction of local reaction are carried out; after the reaction, silicon nitride manganese alloy is obtained. However, this method does not disclose the amount of raw materials used, and chemical stimulants are required.

[0005] Patent publication (CN101619411A) discloses a silicon nitride manganese alloy for steelmaking and a preparation method thereof. The weight percentage composition of the silicon nitride manganese alloy is: Mn: 25% to 75%, Si: 10% to 60%, N: 10% to 38%, and the balance is Fe and other trace elements. The preparation method is as follows: (1) Ordinary silicon manganese and ordinary silicon iron are used as raw materials or ordinary silicon manganese, ordinary silicon iron and metallic manganese are used as raw materials, crushed through a 60 mesh sieve, mixed evenly, and then a polyvinyl alcohol aqueous solution with a mass concentration of 8% accounting for 7% to 9% of the weight of the material is added as a binder for wet mixing to form a spherical object with a particle size of 10 to 40 mm: (2) The spherical object is loaded into a pile and sent into a push plate kiln, high-purity nitrogen is introduced, and a positive pressure of 10 to 70 Pa is always maintained in the kiln, and the reaction sintering is carried out at 1000 to 1250°C for 5 to 7 hours: (3) The high nitrogen silicon manganese alloy is obtained by gradually cooling to below 100°C and taking out of the furnace.

[0006] The problems of this method are: 1. The nitrogen content of the obtained silicon manganese nitride is unstable and the quality of the product cannot reach a stable state; 2. Continuous production and continuous discharge cannot be achieved during the production process, and the production efficiency is not very high; 3. It is necessary to judge how many ignition points to open according to the amount of reaction materials, which increases the workload of the operators, and the ignition points opened are different according to the amount of reaction materials.

[0007] In actual production, the furnace of the horizontal furnace is relatively short, and the material cannot be discharged continuously during the reaction process, so the production efficiency is low. It is not suitable for industrial large-scale production of silicon nitride manganese alloy, and the body density of the generated product is not very high. Summary of the invention

[0008] The invention provides a method for preparing silicon manganese nitride alloy, which solves the problems of unstable fluctuation of nitrogen content in the production process of silicon manganese nitride alloy and low production efficiency and low capacity through the change of ingredients and vertical furnace production.

[0009] The present invention is achieved through the following technical solutions.

[0010] A method for preparing silicon manganese nitride alloy, using a vertical furnace for smelting, comprising:

[0011] High-purity nitrogen is continuously introduced into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and the pressure of the nitrogen in the vertical furnace is maintained to be greater than the atmospheric pressure;

[0012] According to the target smelting silicon nitride manganese alloy composition requirements, electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon are mixed according to the calculated composition ratio and then placed in a vertical furnace;

[0013] The mixed material in the vertical furnace is ignited by electric arc ignition, and when the temperature of the reaction zone in the furnace reaches 850°C to 1200°C, a nitriding reaction is performed to obtain silicon nitride manganese alloy powder, and the prepared silicon nitride manganese alloy powder is discharged from the bottom of the vertical furnace body by sedimentation;

[0014] After the above steps are completed, the mixed material is added into the vertical furnace once every 10 to 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 10 to 20 minutes to obtain silicon nitride manganese alloy.

[0015] The temperature of the reaction zone in the furnace is kept between 850°C and 1200°C by controlling the amount of nitrogen introduced and the amount of material added.

[0016] The mass ratio of electrolytic manganese: silicon manganese alloy: high silicon ferrosilicon used to prepare silicon nitride manganese alloy with manganese content of 0% to 15% and nitrogen content of 25% to 28% is 1:3:6, and the mass fluctuation of each component is allowed to be ≤10%.

[0017] The grade of the high-silicon ferrosilicon is FeSi90, and the grade of the silicon-manganese alloy is 6517.

[0018] The particle size of the electrolytic manganese, silicon-manganese alloy and high-silicon ferrosilicon added into the vertical furnace is 60-80 meshes.

[0019] Silicon nitride manganese alloy smelting device, comprising at least:

[0020] Vertical furnace body;

[0021] A first furnace cover located on the furnace top, the first furnace cover comprising a first exhaust hole for exhausting gas and a first feed port for adding reaction materials;

[0022] A discharge portion located at the bottom of the furnace body, wherein the discharge portion is provided with a discharge port and a baffle plate;

[0023] An air intake structure located below the furnace body, the air intake structure is used to introduce nitrogen into the furnace body;

[0024] A plurality of partitions made of refractory bricks located inside the furnace body, wherein the plurality of partitions divide the interior of the furnace body into a plurality of areas;

[0025] It also includes a second furnace cover, on which a second exhaust hole for exhausting gas, a second feeding port for adding reaction materials, and an electrode for igniting the reaction materials are provided.

[0026] The air intake structure comprises an annular air intake pipeline, an air inlet is connected to the outer side of the annular air intake pipeline, and a plurality of air outlets leading to the inside of the furnace body are connected to the inner circle of the annular air intake pipeline.

[0027] The furnace also includes a cooling unit located below the furnace body, wherein the cooling unit includes a cooling medium channel, a cooling inlet for introducing a cooling medium into the cooling medium channel, and a cooling outlet for discharging the cooling medium.

[0028] The partition is made of refractory bricks, and a cooling medium channel is arranged in the lower inner layer of the partition.

[0029] The technical effects of this application are:

[0030] 1. The ingredients are electrolytic manganese, silicon-manganese alloy, high-silicon ferrosilicon, iron and other trace elements are evenly mixed to stabilize the nitrogen content of the generated silicon nitride manganese alloy at a higher state. It is only necessary to put the electrode in for heating at the beginning of the reaction, and the electrode can be taken away after the reaction starts. In high-silicon ferrosilicon, silicon can burn and achieve self-propagation, so the product quality is stable and the cost is low.

[0031] 2. The interior of a conventional furnace is one area. Since the furnace is too large, the temperature in the middle area is high and the nitriding reaction is sufficient, while the temperature on both sides is low and the nitriding reaction is insufficient. The furnace interior of the present invention is divided into multiple areas by a plurality of partitions. By dividing the furnace interior into multiple areas, the uniformity of the temperature in the furnace can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the silicon nitride manganese alloy smelting device when the second furnace cover is used in the present application;

[0033] Figure 2 It is a schematic diagram of the structure of a silicon nitride manganese alloy smelting device using a first furnace cover and having a partition in the furnace in the present application;

[0034] Figure 3 yes Figure 2 A schematic front cross-sectional view of the structure of a medium silicon nitride manganese alloy smelting device;

[0035] Figure 4 This is a schematic diagram of the structure of a silicon nitride manganese alloy smelting device using a first furnace cover and without a partition in the furnace;

[0036] Figure 5 Schematic diagram of the structure of the silicon nitride manganese alloy smelting device of Examples 1, 3, and 4, and schematic diagram of the charge in the furnace during normal smelting;

[0037] Figure 6 Schematic diagram of the structure of the silicon nitride manganese alloy smelting device of Example 2 and schematic diagram of the distribution of charge in the furnace during normal smelting;

[0038] Figure 7 Schematic diagram of the detection area of ​​silicon manganese nitride alloy samples of Examples 1 to 4;

[0039] Figure 8 This is a schematic diagram of the detection area of ​​the silicon manganese nitride alloy sample of Comparative Example 1;

[0040] In the figure:

[0041] 1. Furnace body;

[0042] 21. first furnace cover; 211. first exhaust hole; 212. first feeding port 22;

[0043] 22. second furnace cover; 221. second exhaust hole; 222. second feed port; 223. electrode;

[0044] 3. Discharging part; 31. Discharging port; 32. Baffle plate;

[0045] 4. Partition;

[0046] 5. Air intake structure; 51. Air intake port; 52. Annular air intake pipeline;

[0047] 6. Cooling unit 6; 61. Cooling medium channel; 62. Cooling inlet; 63. Cooling outlet 63;

[0048] 7. Silo DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In view of the problems existing in the prior art, the present invention provides a method for preparing silicon manganese nitride alloy, which is characterized in that a vertical furnace is used for smelting and preparation, and comprises the following steps:

[0051] High-purity nitrogen is continuously introduced into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and the pressure of the nitrogen in the vertical furnace is maintained to be greater than the atmospheric pressure;

[0052] According to the target smelting silicon nitride manganese alloy composition requirements, electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon are mixed according to the calculated composition ratio and then placed in a vertical furnace;

[0053] The mixed material in the vertical furnace is ignited by electric arc ignition, and when the temperature of the reaction zone in the furnace reaches 850°C to 1200°C, a nitriding reaction is performed to obtain silicon nitride manganese alloy powder, and the prepared silicon nitride manganese alloy powder is discharged from the bottom of the vertical furnace body by sedimentation;

[0054] After the above steps are completed, the mixed material is added into the vertical furnace once every 10 to 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 10 to 20 minutes to obtain silicon nitride manganese alloy.

[0055] According to the present invention, high-purity nitrogen is first used to replace the air in the vertical furnace, the purpose of which is to discharge the oxygen in the vertical furnace from the furnace, and to prevent air from entering the vertical furnace, the pressure of the nitrogen in the vertical furnace is kept greater than the atmospheric pressure, so that the high-purity nitrogen in the vertical furnace is always in a positive pressure state, and the air outside the furnace cannot enter the furnace, thereby ensuring an oxygen-free environment in the furnace. When filling with nitrogen, the furnace body is closed, that is, the discharge part at the bottom of the furnace body and the feed port of the furnace cover are both closed. In order to further ensure that the furnace is in an oxygen-free environment, the vertical furnace can be evacuated first, and then high-purity nitrogen is continuously filled into the furnace, and the nitrogen pressure in the furnace is kept greater than the atmospheric pressure. Specifically, the nitrogen pressure in the furnace can be higher than 0.11Mpa. Excessive nitrogen pressure in the furnace will also have a certain impact on the furnace body. Therefore, it is preferred to maintain the nitrogen pressure in the vertical furnace at 0.2Mpa~0.8Mpa.

[0056] According to the present invention, after the furnace is filled with nitrogen, the feeding can be started. The raw materials for smelting silicon manganese nitride alloy used in the present invention are electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon. Specifically, according to the target requirements for smelting silicon manganese nitride alloy components, electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon are mixed according to the calculated component ratio and then put into a vertical furnace. In some preferred embodiments of the present invention, the mass ratio of electrolytic manganese: silicon manganese alloy: high silicon ferrosilicon configured for preparing silicon manganese nitride alloy with a manganese content of 0% to 15% and a nitrogen content of 25% to 28% is 1:3:6, and the mass fluctuation of each component is allowed to be ≤10%. In the embodiment of the present invention, the preferred grade of high silicon ferrosilicon is FeSi90, and the grade of silicon manganese alloy is 6517.

[0057] In some embodiments of the present invention, the particle size of the electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 60 mesh to 80 mesh, which can be 60 mesh, 70 mesh, 80 mesh, etc., or it can be according to the normal distribution trend of the particle size, and the particle size of 2σ to 6σ is in the range of 60 mesh to 80 mesh, that is, the raw material distribution range of the particle size of 60 mesh to 80 mesh is 95% to 100%, which can be 95% of the particle size in the range of 60 mesh to 80 mesh, 99% of the particle size in the range of 60 mesh to 80 mesh, or 100% of the particle size in the range of 60 mesh to 80 mesh.

[0058] According to the present invention, when the furnace is filled with electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon mixed raw materials, the mixed materials begin to be ignited. The present invention uses an arc ignition method to ignite the mixed materials in the vertical furnace. When the temperature of the reaction zone in the furnace reaches 850°C to 1200°C, a nitriding reaction is carried out to obtain silicon nitride manganese alloy powder. The prepared silicon nitride manganese alloy powder is discharged from the bottom of the vertical furnace body by sedimentation.

[0059] Since the materials in the vertical furnace are all fine powders with small particle sizes, during the material ignition process, the fine powders in the vertical furnace will be ignited by the electric arc and will undergo a deflagration process. Since the nitriding process of the silicon carbide manganese alloy is an exothermic process, the materials in the furnace will be heated after being spread and ignited. When the temperature reaches 850°C, the nitriding reaction begins, and when the temperature exceeds 1350°C, the silicon nitride manganese alloy will decompose. Therefore, in some embodiments of the present invention, the temperature of the reaction zone in the furnace is between 850°C and 1200°C by controlling the amount of nitrogen introduced and the amount of material added.

[0060] In the vertical furnace used in the present invention, Figure 5 , Figure 6 The furnace area can be divided from top to bottom into charging zone, preheating zone, reaction zone, and cooling zone. Except for the cooling zone, the above zones are artificial conceptual divisions to distinguish materials in different reaction processes. There are no clear boundaries between the zones in the vertical furnace.

[0061] During the first smelting, the vertical furnace needs to be filled with mixed raw materials of electrolytic manganese, silicon-manganese alloy and high-silicon ferrosilicon in the feeding zone, preheating zone, reaction zone and cooling zone. During the first smelting, the materials in the feeding zone, preheating zone and reaction zone may undergo nitriding reaction at the same time to obtain silicon-manganese nitride alloy, the materials in the feeding zone and preheating zone may undergo nitriding reaction at the same time to obtain silicon-manganese nitride alloy, and the materials in the feeding zone may undergo nitriding reaction to obtain silicon-manganese nitride alloy.

[0062] When the materials in the feeding zone, preheating zone and reaction zone are simultaneously subjected to nitridation reaction to obtain silicon manganese nitride alloy, the materials in the cooling zone are discharged by sedimentation, and the silicon manganese nitride alloy generated by the reaction is deposited in the cooling zone, and the materials in other zones are deposited in the reaction zone and preheating zone in turn. At this time, space is reserved in the feeding zone, and the reaction mixture is added to the feeding zone. After the cooling of the silicon manganese nitride alloy in the cooling zone is completed, the materials in the reaction zone have generated silicon manganese nitride alloy, and continue to be deposited in the cooling zone for cooling. The materials in the original feeding zone enter the preheating zone, and the materials in the reaction zone heat the materials in the preheating zone and start to slowly self-propagate combustion. When the materials in the preheating zone enter the reaction zone, the material temperature reaches between 850°C and 1200°C. After about 10min to 20min, the materials in the reaction zone generate silicon manganese nitride alloy, and continue to settle the silicon manganese nitride alloy in the reaction zone to the cooling zone by sedimentation for cooling and discharging.

[0063] According to the present invention and the above-mentioned feeding method, the mixed material is added into the vertical furnace once every 10 to 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 10 to 20 minutes to obtain silicon nitride manganese alloy.

[0064] like Figures 1 to 6 The present invention also provides a silicon nitride manganese alloy smelting device for the above method, which at least includes: a vertical furnace body 1; a first furnace cover 21 located at the top of the furnace, the first furnace cover 21 includes a first exhaust hole 211 for exhausting gas, and a first charging port 212 for adding reaction materials; a discharge portion 3 located at the bottom of the furnace body, and a material collecting device may be provided at the discharge portion 3; an air intake structure 5 located below the furnace body 1, and the air intake structure 5 is used to introduce nitrogen into the furnace body; a plurality of partitions 4 made of refractory bricks located inside the furnace body 1, and the plurality of partitions 4 divide the interior of the furnace body 1 into a plurality of areas; and also includes a second furnace cover 22, which is provided with a second exhaust hole 221 for exhausting gas, a second charging port 222 for adding reaction materials, and an electrode 223 for igniting the reaction materials.

[0065] In the present invention, the furnace structure is a vertical furnace, which is a self-propagating furnace. The top of the furnace body 1 is charged with materials, and the discharge part 3 is located at the bottom of the furnace body. The discharge part 3 is provided with a discharge port 31 and a baffle plate 32; the baffle plate 32 is used to block the sedimentation of materials, and a silo 7 for collecting materials is provided below the discharge part. The furnace body is made of refractory bricks as a whole, and the furnace body structure is sealed and airtight.

[0066] The air intake structure 5 is located below the furnace body and is used to introduce nitrogen into the furnace. The optional air intake mechanism can be a separate air intake pipe, through which nitrogen is introduced into the furnace body, or it can be a preferred air intake structure 5 of the present invention. The preferred air intake structure 5 includes an annular air intake pipeline 52, an air inlet 51 is connected to the outer side of the annular air intake pipeline 52, and a plurality of air outlets leading to the interior of the furnace body 1 are connected to the inner circle of the annular air intake pipeline 3. In this preferred air intake structure, nitrogen enters the annular air intake pipeline 52 from the air inlet 51. After the nitrogen enters the annular air intake pipeline 52, the nitrogen is distributed and discharged into the furnace body through a plurality of air outlets 53 on the inner side of the annular air intake pipeline 52.

[0067] The interior of a conventional furnace body is one area. Since the furnace body is too large, the temperature in the middle area is high and the nitriding reaction is sufficient, while the temperature on both sides is low and the nitriding reaction is insufficient. The furnace body of the present invention divides the interior of the furnace body 1 into multiple areas through a plurality of partitions 7, such as Figure 2 , Figure 4 , by dividing the furnace area into multiple zones, the uniformity of the furnace temperature can be improved.

[0068] The furnace cover of the present invention is equipped with a first furnace cover 21 and a second furnace cover 22, wherein the second furnace cover 22 is used for charging and igniting materials when the smelting furnace performs smelting for the first time. After the materials are ignited for the first time, the second furnace cover 22 is replaced by the first furnace cover 21 for charging.

[0069] In order to further improve the cooling efficiency of the silicon nitride manganese alloy at the bottom of the furnace, in an optional embodiment, the silicon nitride manganese alloy smelting device of the present invention also includes a cooling unit 6 located below the furnace body, and the cooling unit 6 includes a cooling medium channel 61, a cooling inlet 62 for introducing the cooling medium into the cooling medium channel, and a cooling outlet 63 for discharging the cooling medium. In this optional embodiment, the cooling medium in the specific optional embodiment can be cold water or cold air or cooling oil, etc. The cooling medium channel 61 can be selected as a spiral coil, or an upper and lower circulation pipeline can be selected, or a cooling liquid tank surrounding the furnace body can be selected. In an optional embodiment, the position of the cooling inlet 62 is lower than the position of the cooling outlet 63. This arrangement can ensure that the cooling medium channel 61 is filled with cooling medium. In a further optional embodiment, the partition 7 is made of refractory bricks, and a cooling medium channel is provided in the lower inner layer of the partition 4.

[0070] In the present invention, Figures 1 to 3 , Embodiments 1 to 4 use a first furnace cover 21b, the first furnace cover 21b includes a first exhaust hole 211b for exhausting gas, and a plurality of first feed ports 212b for adding reaction materials;

[0071] Comparative Example 1 uses a first furnace cover 21a, which includes a first exhaust hole 211a for exhausting gas and a first feed port 212a for adding reaction materials;

[0072] In order to further illustrate the present invention, the following examples are provided for detailed description. The experimental raw materials used in the following examples of the present invention can be purchased from the market or prepared according to conventional preparation methods well known to those skilled in the art.

[0073] Example 1

[0074] like Figure 1 , Figure 2 , Figure 3 , Figure 5 When a vertical furnace is used, a conventional silicon nitride manganese alloy smelting device is used to prepare silicon nitride manganese alloy. The vertical furnace has a partition 4. The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0075] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0076] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0077] After the vertical furnace is filled with nitrogen, the mixed materials of electrolytic manganese (Mn 99%), silicon-manganese alloy (grade 6517), and high-silicon ferrosilicon (grade FeSi90) with a particle size of 60-80 mesh are put into the vertical furnace. The mass ratio of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 1:3:6, wherein; when adding for the first time, the vertical furnace is filled with the mixed materials;

[0078] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover 22 is replaced with the first furnace cover 21. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0079] Open the discharge part 3 at the bottom of the furnace body, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 20 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, continue to open the discharge part, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After closing the furnace and discharging, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0080] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃. It takes 20 minutes for the material with a thickness of 3 meters to be completely nitrided. The temperature of the reaction zone in the furnace is kept between 850℃ and 1200℃ by controlling the amount of nitrogen introduced and the amount of material added. When the temperature in the furnace exceeds 1200℃, the flow rate of nitrogen introduced is increased. The material in the first furnace is not used as the final product.

[0081] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 20 minutes to obtain silicon nitride manganese alloy.

[0082] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 7 , which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, see Table 1 for details.

[0083] Example 2

[0084] like Figure 1 , Figure 2 , Figure 3 , Figure 6 When a vertical furnace is used, a conventional silicon nitride manganese alloy smelting device is used to prepare silicon nitride manganese alloy. The vertical furnace has a partition 4. The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0085] The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0086] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0087] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0088] After the vertical furnace is filled with nitrogen, a mixture of electrolytic manganese (Mn99%), silicon-manganese alloy (grade 6517), and high-silicon ferrosilicon (grade FeSi90) with a particle size of 60-80 mesh is placed in the vertical furnace. The mass ratio of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 1.1:3.3:5.6, wherein; when first added, the vertical furnace is filled with the above mixed materials;

[0089] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover is replaced with the first furnace cover. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0090] The discharge part at the bottom of the furnace body is opened, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 20 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, the discharge part is continued to be opened, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After the furnace is closed and discharged, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0091] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃, and it takes 10 minutes for the material with a thickness of 3 meters to be completely nitrided. It should be noted that in the first furnace, the ignition starts from the top of the furnace body, so due to the long heating time, the temperature of some areas in the furnace will reach above 1300℃, causing product decomposition. Therefore, before the first round of materials are completely discharged, the materials of the first furnace are not used as the final product, and the unqualified products of this furnace can be used as raw materials to re-enter the furnace for reaction.

[0092] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 10 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 10 minutes to obtain silicon nitride manganese alloy.

[0093] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 7 , which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, see Table 1 for details.

[0094] Example 3

[0095] like Figure 1 , Figure 2 , Figure 3 , Figure 5 When a vertical furnace is used, a conventional silicon nitride manganese alloy smelting device is used to prepare silicon nitride manganese alloy. The vertical furnace has a partition 4. The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0096] The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0097] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0098] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0099] After the vertical furnace is filled with nitrogen, the mixed materials of electrolytic manganese (Mn 99%), silicon-manganese alloy (grade 6517), and high-silicon ferrosilicon (grade FeSi90) with a particle size of 60-80 mesh are put into the vertical furnace. The mass ratio of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 1.1:3.2:5.7, wherein; when adding for the first time, the vertical furnace is filled with the mixed materials;

[0100] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover is replaced with the first furnace cover. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0101] The discharge part at the bottom of the furnace body is opened, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 15 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, the discharge part is continued to be opened, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After the furnace is closed and discharged, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0102] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃, and it takes 10 minutes for the material with a thickness of 3 meters to be completely nitrided. It should be noted that in the first furnace, the ignition starts from the top of the furnace body, so due to the long heating time, the temperature of some areas in the furnace will reach above 1300℃, causing product decomposition. Therefore, before the first round of materials are completely discharged, the materials of the first furnace are not used as the final product, and the unqualified products of this furnace can be used as raw materials to re-enter the furnace for reaction.

[0103] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 15 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 15 minutes to obtain silicon nitride manganese alloy.

[0104] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 7 , which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, see Table 1 for details.

[0105] Example 4

[0106] like Figure 1 , Figure 2 , Figure 3 , Figure 5 When a vertical furnace is used, a conventional silicon nitride manganese alloy smelting device is used to prepare silicon nitride manganese alloy. The vertical furnace has a partition 4. The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0107] The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0108] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0109] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0110] After the vertical furnace is filled with nitrogen, the mixed materials of electrolytic manganese (Mn 99%), silicon-manganese alloy (grade 6517), and high-silicon ferrosilicon (grade FeSi90) with a particle size of 60-80 mesh are put into the vertical furnace. The mass ratio of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 0.9:2.8:6.3, wherein; when first added, the vertical furnace is filled with the mixed materials;

[0111] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover is replaced with the first furnace cover. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0112] Open the discharge part 3 at the bottom of the furnace body, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 20 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, continue to open the discharge part, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After closing the furnace and discharging, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0113] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃. It takes 20 minutes for the material with a thickness of 3 meters to be completely nitrided. The temperature of the reaction zone in the furnace is kept between 850℃ and 1200℃ by controlling the amount of nitrogen introduced and the amount of material added. When the temperature in the furnace exceeds 1200℃, the flow rate of nitrogen introduced is increased. The material in the first furnace is not used as the final product.

[0114] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 20 minutes to obtain silicon nitride manganese alloy.

[0115] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 7, which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, see Table 1 for details.

[0116] Comparative Example 1

[0117] Use Figure 4 The vertical furnace shown is the silicon nitride manganese alloy smelting device of the present application for preparing silicon nitride manganese alloy, and the vertical furnace does not have a partition 4.

[0118] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0119] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0120] After the vertical furnace is filled with nitrogen, the mixed materials of electrolytic manganese (Mn 99%), silicon-manganese alloy (grade 6517), and high-silicon ferrosilicon (grade FeSi90) with a particle size of 60-80 mesh are put into the vertical furnace. The mass ratio of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon is 1:3:6, wherein; when adding for the first time, the vertical furnace is filled with the mixed materials;

[0121] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover 22 is replaced with the first furnace cover 21. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0122] Open the discharge part 3 at the bottom of the furnace body, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 20 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, continue to open the discharge part, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After closing the furnace and discharging, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0123] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃. It takes 20 minutes for the material with a thickness of 3 meters to be completely nitrided. The temperature of the reaction zone in the furnace is kept between 850℃ and 1200℃ by controlling the amount of nitrogen introduced and the amount of material added. When the temperature in the furnace exceeds 1200℃, the flow rate of nitrogen introduced is increased. The material in the first furnace is not used as the final product.

[0124] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 20 minutes to obtain silicon nitride manganese alloy.

[0125] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 8 , which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, as shown in Table 1 for details.

[0126] Comparative Example 2

[0127] Use Figure 4 The vertical furnace shown is the silicon nitride manganese alloy smelting device of the present application for preparing silicon nitride manganese alloy, and the vertical furnace does not have a partition 4.

[0128] The furnace body length of the silicon nitride manganese alloy smelting device used in this embodiment is 12m, and the furnace inner diameter is 120cm.

[0129] A method for preparing a silicon manganese nitride alloy comprises the following steps:

[0130] Close all openings of the furnace body, evacuate the vertical furnace, make the gas pressure in the furnace less than 60kpa, and then continuously introduce high-purity nitrogen with a purity of ≥99.95% into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and maintain the nitrogen pressure in the vertical furnace at 0.2-0.8Mpa;

[0131] After the vertical furnace is filled with nitrogen, a mixture of silicon manganese powder (Mn 75%) with a particle size of 60-80 mesh, ferrosilicon (Si75%), and a chemical stimulant (polyvinyl chloride) is placed in the vertical furnace, and the mass ratio of silicon manganese powder, ferrosilicon, and chemical stimulant (polyvinyl chloride) is 2.5:7.5:1; when the vertical furnace is added for the first time, the vertical furnace is filled with the above mixed materials;

[0132] After the mixed material in the shaft furnace is filled, the mixed material in the shaft furnace is ignited by arc ignition using the electrode 223 on the second furnace cover 22. After ignition, the second furnace cover is replaced with the first furnace cover. After 40 minutes, the material located 6 meters above the furnace body generates silicon carbide silicon manganese iron;

[0133] Open the discharge part 3 at the bottom of the furnace body, and the material descends. When the material 6 meters above the furnace body enters the cooling zone at the bottom of the furnace body, the feeding zone and the preheating zone are vacated, and the mixed material continues to be introduced into the feeding zone and the preheating zone. Due to the self-propagating reaction effect, the material in the reaction zone begins to heat the mixed material in the preheating zone. After heating for 20 minutes, the material temperature at the bottom of the preheating zone reaches 850°C. At this time, continue to open the discharge part, and the silicon nitride manganese iron in the cooling zone is discharged from the furnace. The silicon nitride manganese iron in the reaction zone is deposited and enters the cooling zone. After closing the furnace and discharging, the materials in the feeding zone and the preheating zone are settled. The materials in the preheating zone enter the reaction zone. After the materials in the feeding zone enter the preheating zone, the feeding zone is vacated, and the mixed material is continued to be heated in the furnace through the first feeding port 212 located on the first furnace cover 21 to fill the feeding zone.

[0134] In the reaction zone, the temperature of the material rises from 850℃ to 1200℃. It takes 20 minutes for the material with a thickness of 3 meters to be completely nitrided. The temperature of the reaction zone in the furnace is kept between 850℃ and 1200℃ by controlling the amount of nitrogen introduced and the amount of material added. When the temperature in the furnace exceeds 1200℃, the flow rate of nitrogen introduced is increased. The material in the first furnace is not used as the final product.

[0135] After the first furnace is completely discharged, the mixed material is added into the vertical furnace once every 20 minutes for self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 20 minutes to obtain silicon nitride manganese alloy.

[0136] The composition of silicon manganese nitride alloy after furnace is tested. The test area is as follows: Figure 8 , which is the center area A with a center radius of 15 cm, and the area B with a radius ranging from 40 cm to 50 cm, see Table 1 for details.

[0137] The composition of the silicon manganese nitride alloy after being fired is shown in Table 1.

[0138] Table 1 Composition of silicon manganese nitride alloys obtained in various embodiments and comparative examples

[0139]

[0140] The ingredients of Examples 1 to 4 of the present application are a mixture of electrolytic manganese, silicon-manganese alloy, and high-silicon ferrosilicon so that the nitrogen content of the generated silicon nitride manganese alloy can be stabilized at a relatively high state, and the electrodes only need to be placed in for heating at the beginning of the reaction, and the electrodes can be removed after the reaction starts. In high-silicon ferrosilicon, silicon can burn and achieve self-propagation, without the need for an excitant, the product quality is stable, and the cost is relatively low.

[0141] It can be seen from Examples 1 to 4 and Comparative Example 1 that the material composition of each region in Examples 1 to 4 is basically the same, while the material composition of each region in Comparative Example 1 is quite different. The interior of a conventional furnace body is one region. Since the furnace body is too large, the temperature in the middle region is high and the nitriding reaction is sufficient, while the temperature on both sides is low and the nitriding reaction is insufficient. The furnace body of the present invention divides the interior of the furnace body into multiple regions through a plurality of partitions. By dividing the furnace area into multiple regions, the uniformity of the temperature in the furnace can be improved.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing silicon manganese nitride alloy, characterized in that: The smelting preparation is carried out using a vertical furnace, including: High-purity nitrogen is continuously introduced into the vertical furnace to completely replace the oxygen in the vertical furnace with nitrogen, and the pressure of the nitrogen in the vertical furnace is maintained to be greater than the atmospheric pressure; According to the target smelting silicon nitride manganese alloy composition requirements, electrolytic manganese, silicon manganese alloy, and high silicon ferrosilicon are mixed according to the calculated component ratio and then put into a vertical furnace, the grade of the high silicon ferrosilicon is FeSi90, the grade of the silicon manganese alloy is 6517, the mass ratio of the electrolytic manganese: silicon manganese alloy: high silicon ferrosilicon is 1:3:6, and the mass fluctuation of each component is allowed to be ≤10%; The mixed material in the vertical furnace is ignited by electric arc ignition, and when the temperature of the reaction zone in the furnace reaches 850°C to 1200°C, a nitriding reaction is performed to obtain silicon nitride manganese alloy powder, and the prepared silicon nitride manganese alloy powder is discharged from the bottom of the vertical furnace body by sedimentation; After the above steps are completed, the mixed material is added into the vertical furnace once every 10 to 20 minutes to carry out a self-propagating reaction, and the material is discharged from the bottom of the vertical furnace once every 10 to 20 minutes to obtain a silicon nitride manganese alloy; The smelting device of the silicon manganese nitride alloy at least comprises: A vertical furnace body (1); A plurality of partitions (4) made of refractory bricks are located inside the furnace body (1), and the plurality of partitions (4) divide the interior of the furnace body (1) into a plurality of areas.

2. The method for preparing silicon manganese nitride alloy according to claim 1, characterized in that: The temperature of the reaction zone in the furnace is kept between 850°C and 1200°C by controlling the amount of nitrogen introduced and the amount of material added.

3. The method for preparing silicon manganese nitride alloy according to claim 1, characterized in that: The method is used for preparing a silicon manganese nitride alloy with a manganese content of 0% to 15% and a nitrogen content of 25% to 28%.

4. The method for preparing the silicon manganese nitride alloy according to any one of claims 1 or 3, characterized in that: The particle size of the electrolytic manganese, silicon-manganese alloy and high-silicon ferrosilicon added into the vertical furnace is 60-80 meshes.

5. A silicon nitride manganese alloy smelting device used in the method according to any one of claims 1 to 4, characterized in that: At least: A vertical furnace body (1); A first furnace cover (21) located on the furnace top, the first furnace cover (21a; 21b) comprising a first exhaust hole (211a; 211b) for exhausting gas and a first feed port (212a; 212b) for adding reaction materials; A discharge portion (3) located at the bottom of the furnace body, wherein the discharge portion (3) is provided with a discharge port (31) and a baffle plate (32); An air intake structure (5) located below the furnace body (1), the air intake structure (5) being used to introduce nitrogen into the furnace body; A plurality of partitions (4) made of refractory bricks and located inside the furnace body (1), wherein the plurality of partitions (4) divide the interior of the furnace body (1) into a plurality of areas; It also includes a second furnace cover (22), on which is provided a second exhaust hole (221) for exhausting gas, a second feed port (222) for adding reaction materials, and an electrode (223) for igniting the reaction materials.

6. The silicon nitride manganese alloy smelting device according to claim 5, characterized in that: The air intake structure (5) comprises an annular air intake pipeline (52), an air intake port (51) connected to the outer side of the annular air intake pipeline (52), and a plurality of air outlets connected to the interior of the furnace body (1) at the inner circle of the annular air intake pipeline (52).

7. The silicon nitride manganese alloy smelting device according to claim 5, characterized in that: It also includes a cooling unit (6) located below the furnace body, the cooling unit (6) including a cooling medium channel (61), a cooling inlet (62) for introducing a cooling medium into the cooling medium channel, and a cooling outlet (63) for discharging the cooling medium.

8. The silicon nitride manganese alloy smelting device according to claim 7, characterized in that: The partition plate (4) is made of refractory bricks, and a cooling medium channel is provided in the lower inner layer of the partition plate (4).

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