Modification method for ultrafine silicon micropowder having solvent recovery function

Abstract

A modification method for ultrafine silicon micropowder having a solvent recovery function, comprising: dissolving a modified resin in a hexafluoropropene trimer solvent; weighing a specified amount of a modified resin solvent, mixing with a specified amount of the solvent and stirring; placing ultrafine silicon micropowder into the mixed solvent to perform a silicon micropowder dispersion reaction; recovering the solvent by vacuum distillation; drying the modified silicon micropowder mixture after solvent distillation recovery, to obtain a modified silicon micropowder. Using an organic phase as a solvent can better dissolve the modified resin and increase the hydrophobicity of the surface of the silicon micropowder. In addition, a designed modification solvent recovery apparatus can realize solvent recovery during a modification process, thereby improving solvent recovery efficiency and a solvent recovery rate.

Description

A modification method for ultrafine silicon powder with solvent recovery function Technical Field

[0001] The invention belongs to the field of semiconductors and relates to a modification process of silicon micropowder, in particular to a modification method of ultrafine silicon micropowder with a solvent recovery function. Background Art

[0002] Submicron and nano-sized silica powders have a larger specific surface area than micron-sized silica powders. Direct use of these materials can lead to problems such as high system viscosity and difficulty dispersing them, necessitating surface modification. Surface modification of silica powders produced domestically and internationally can be broadly categorized into two methods: dry and wet. Dry modification offers a simple process but lower production efficiency. Furthermore, the modifiers are difficult to evenly disperse on the silica powder surface, resulting in poor modification results. Dry modification is only suitable for surface modification of silica powders larger than micron size.

[0003] Submicron and nanometer-sized silicon powders require wet modification. Wet modification can cause submicron and nanometer-sized silicon powders to agglomerate after drying, making it impossible to achieve independent dispersion of the silicon powder particles. This can affect the product's performance and prevent it from achieving the desired effect of submicron and nanometer-sized fillers.

[0004] At present, the modification is to add the modifier directly to the suspension solution dispersed with silicon micropowder after dissolving it, stir and mix it thoroughly, and then dry it. This consumes a lot of modifier and solvent, the dispersion effect is uneven, and the costs in all aspects are high.

[0005] The existing modification methods of ultrafine silicon powder have problems such as serious waste of modifiers and solvents, uneven modification effects, large investment of manpower and material resources, and difficult operation. A new technical solution is needed to solve these problems.

[0006] Summary of the Invention

[0007] Purpose of the invention: In order to overcome the shortcomings of the existing technology, a method for modifying ultrafine silicon micropowder with solvent recovery function is provided, in which an organic phase is used as a solvent to better dissolve the modified resin and improve the hydrophobicity of the silicon micropowder surface. The designed modified solvent recovery device can realize the recovery of the solvent during the modification process, and has excellent solvent recovery efficiency and solvent recovery rate.

[0008] Technical solution: To achieve the above purpose, the present invention provides a method for modifying ultrafine silicon powder with solvent recovery function, comprising the following steps:

[0009] S1: dissolving the modified resin in a solvent of hexafluoropropylene trimer;

[0010] S2: Weigh a specified amount of the modified resin solvent from step S1, mix it with a specified amount of hexafluoropropylene trimer solvent, and then stir;

[0011] S3: adding the ultrafine silicon powder into the mixed solvent of step S2 to perform a silicon powder dispersion reaction;

[0012] S4: recovering the solvent by vacuum distillation;

[0013] S5: drying the modified silicon micropowder mixture after the solvent is distilled and recovered to obtain modified silicon micropowder.

[0014] Furthermore, in step S1, the ratio of the modified resin in the solvent is 4-6‰, the dissolution temperature is 50-60°C, and the dissolution time is 1-6 hours.

[0015] Furthermore, the modified resin in step S1 is a fluorine-containing resin, selected from any one or a combination of at least two of polytetrafluoroethylene, perfluorosulfonic acid resin, perfluorocarboxylic acid resin, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, perfluoro-2,5-dimethyl-3,6-dioxanoic acid, perfluoro-2,5-dimethyl-3,6-dioxaheptanoic acid, 2-(perfluoropropoxy)perfluoropropyl trifluorovinyl ether, perfluorosilane coupling agent, (3,3,3-trifluoropropyl)trimethoxysilane, and heptafluorodecyltrimethoxysilane.

[0016] Furthermore, in step S2, the mass ratio of the modified resin solvent to the solvent is 1:2.

[0017] Furthermore, the operation process of the silicon powder dispersion reaction in step S3 is: adding the ultrafine silicon powder into the mixed solvent, adding the materials while stirring, and heating after the addition is completed to carry out the dispersion reaction.

[0018] Furthermore, in the silicon powder dispersion reaction, after the feeding is completed, the temperature is controlled at 80-100° C., the stirring speed is 500-800 r / min, and the dispersion time is 1 hour.

[0019] Furthermore, the step S4 is specifically as follows: continuing to heat the uniformly mixed ultrafine silicon powder, performing vacuum distillation while stirring, and stopping stirring when the solvent is further reduced to one third of the volume remaining, directly performing vacuum distillation to recover the solvent.

[0020] It should be emphasized here that when the solvent is reduced to one-third of the volume, the viscosity of the ultrafine silicon powder solution increases, so it is necessary to uniformly heat the bottom of the ultrafine silicon powder solution and use vacuum to successfully remove and recover the remaining solvent.

[0021] Furthermore, in step S4, the ultrafine silicon powder after being mixed uniformly is further heated to 106-112°C.

[0022] Furthermore, in step S4, a modified solvent recovery device is used to recover the solvent, and the modified solvent recovery device includes a reactor, a temperature control probe, a mechanical stirrer, a clamp, a heating pack, a dry ice basin, a condenser and a cold hydrazine;

[0023] The reactor is used to provide a reaction space; the mechanical stirrer is used for stirring and dispersing; the temperature control probe is used to detect the reaction temperature; the clamp is used to lock the reactor to ensure the vacuum degree inside the reactor; the heating pack is used to achieve uniform heating of the bottom of the reactor; the dry ice basin is used to create a temperature difference to guide the solvent gas from the high-temperature area of ​​the reactor to the low-temperature area of ​​the dry ice basin; the condenser is used to condense the solvent gas into a liquid state and enter the dry ice basin; the cold hydrazine is used to control gas escape and protect the vacuum pump.

[0024] The specific process of using the modified solvent recovery device to recover the solvent in step S4 is as follows:

[0025] Ultrafine silicon powder and solvent are dispersed and reacted in the reactor under the action of a mechanical stirrer. As the temperature in the reactor rises, the vaporized solvent enters the condenser due to the temperature difference. The condenser condenses the solvent gas into liquid and enters the dry ice basin to achieve solvent recovery.

[0026] When the solvent volume is further reduced to one third, the bottom of the ultrafine silicon powder solution is evenly heated by a heating pack, stirring is stopped, and vacuum distillation is performed directly until the remaining solvent enters the dry ice basin.

[0027] This invention primarily addresses the selection of solvents in the wet-process modification of silicon micropowder and its enhanced modification effect. Wet modification involves wetting the surface of the silicon micropowder in a liquid phase to reduce the surface binding energy. A certain amount of surface modifier and additive is then added, and the mixture is stirred and dispersed at a certain temperature to achieve surface modification of the silicon micropowder. This wet modification process makes the silicon micropowder and modifier more easily dispersed and more fully combined, resulting in more uniform modification and is particularly suitable for modifying ultrafine silicon micropowders with a particle size of less than 5 μm.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0029] 1. The present invention aims to enhance the hydrophobicity of the surface of silicon micropowder. Hexafluoropropylene trimer is selected to dissolve the modifier, so that the long fatty chain of the modifier is stretched in the hexafluoropropylene trimer and then grafted onto the hydroxyl group of the silicon micropowder, thereby enhancing the hydrophobicity of the silicon micropowder and the steric hindrance effect between particles, thereby improving the modification effect on the surface of the silicon micropowder.

[0030] 2. The present invention designs a modified solvent recovery device, which, in conjunction with the process of the present invention, can realize the recovery of the solvent during the modification process. It is not only simple to operate and has high recovery efficiency, but also can achieve an extremely high solvent recovery rate, greatly reducing the loss during the modification process of ultrafine silicon powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of a modified solvent recovery device;

[0032] FIG2 is a mechanism diagram of perfluorosilane coupling agent modified silicon powder; DETAILED DESCRIPTION

[0033] The present invention is further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0034] Example 1:

[0035] This embodiment provides a method for modifying ultrafine silicon powder with a solvent recovery function, comprising the following steps:

[0036] S1: Modified resin dissolution:

[0037] The modified resin is a fluorine-containing resin. In this embodiment, a perfluorosilane coupling agent is selected. The perfluorosilane coupling agent is dissolved in a hexafluoropropylene trimer solvent at a ratio of 5‰. The dissolution temperature is 55°C and the dissolution time is 1 hour to obtain a modified resin solvent.

[0038] S2: Weigh 200 parts of a modified resin solvent, mix it with 400 parts of a hexafluoropropylene trimer solvent, and stir thoroughly to obtain a mixed solvent;

[0039] S3: Silica powder dispersion:

[0040] 200 parts of ultrafine silicon powder were added to the mixed solvent, and the mixture was added while stirring. After the addition was completed, the temperature was raised and controlled at 90°C. The stirring speed was 700 r / min and the dispersion time was 1 hour.

[0041] S4: Recover the solvent by vacuum distillation:

[0042] The mixed ultrafine silicon powder is heated to 109°C and vacuum distilled while stirring. When the solvent volume is reduced to one third, stirring is stopped and vacuum distillation is performed directly to recover the solvent.

[0043] In this embodiment, a modified solvent recovery device is used to recover the solvent. Referring to Figure 1, the modified solvent recovery device includes a reactor 8, a temperature control probe 1, a mechanical stirrer 2, a clamp 3, a heating package 4, a dry ice basin 5, a condenser 6 and a cold hydrazine 7. The temperature control probe 1, the mechanical stirrer 2 and the clamp 3 are arranged on the reactor 8, the heating package 4 is arranged at the bottom of the reactor 8, the two ends of the condenser 6 are respectively connected to the reactor 8 and the dry ice basin 5, and the cold hydrazine 7 is also connected to the condenser 6 and the dry ice basin 5.

[0044] The reactor 8 is used to provide a reaction space; the mechanical stirrer 2 is used for stirring and dispersing; the temperature control probe 1 is used to detect the reaction temperature; the clamp 3 is used to lock the reactor 8 to ensure the vacuum degree inside the reactor 8; the heating pack 4 is used to achieve uniform heating of the bottom of the reactor 8; the dry ice basin 5 is used to create a temperature difference to guide the solvent gas from the high-temperature area of ​​the reactor 8 to the low-temperature area of ​​the dry ice basin 5; the condenser 6 is used to condense the solvent gas into a liquid and enter the dry ice basin 5; the cold hydrazine 7 is used to control gas escape and protect the vacuum pump.

[0045] 1, the specific process of using the modified solvent recovery device to recover the solvent is as follows:

[0046] Ultrafine silicon powder and solvent are dispersed and reacted in the reactor 8 under the action of the mechanical stirrer 2. As the temperature in the reactor 8 rises, the vaporized solvent enters the condenser 6 due to the temperature difference. The condenser 6 condenses the solvent gas into liquid and enters the dry ice basin 5 to achieve solvent recovery.

[0047] When the solvent volume is further reduced to one third, the bottom of the ultrafine silicon powder solution is evenly heated by the heating pack 4, stirring is stopped, and vacuum distillation is directly performed until the remaining solvent enters the dry ice basin 5.

[0048] S5: Drying into powder:

[0049] The modified silicon micropowder mixture after solvent distillation and recovery was placed in a 180° C. forced air oven for 2 hours to obtain modified silicon micropowder.

[0050] Figure 2 is a diagram showing the mechanism of modification of silicon micropowder by a silane coupling agent, wherein the R group is a long fluorine-containing chain. Referring to Figure 2 , the present invention aims to enhance the hydrophobicity of the surface of silicon micropowder, and uses a hexafluoropropylene trimer to dissolve the modifier, so that the long fatty chain of the modifier stretches in the hexafluoropropylene trimer and is then grafted onto the hydroxyl group of the silicon micropowder, thereby enhancing the hydrophobicity of the silicon micropowder and the steric hindrance effect between particles, thereby improving the modification effect on the surface of the silicon micropowder.

[0051] Example 2:

[0052] This embodiment provides a method for modifying ultrafine silicon powder with a solvent recovery function, comprising the following steps:

[0053] S1: Modified resin dissolution:

[0054] The modified resin is a fluorine-containing resin. In this embodiment, ethylene-tetrafluoroethylene copolymer is selected. The ethylene-tetrafluoroethylene copolymer is dissolved in a hexafluoropropylene trimer solvent at a ratio of 4‰. The dissolution temperature is 50°C and the dissolution time is 4 hours to obtain a modified resin solvent.

[0055] S2: Weigh 200 parts of a modified resin solvent, mix it with 400 parts of a hexafluoropropylene trimer solvent, and stir thoroughly to obtain a mixed solvent;

[0056] S3: Silica powder dispersion:

[0057] 200 parts of ultrafine silicon powder were added to the mixed solvent, and the mixture was added while stirring. After the addition was completed, the temperature was raised and controlled at 80°C, the stirring speed was 500 r / min, and the dispersion time was 1 hour;

[0058] S4: Recover the solvent by vacuum distillation:

[0059] The mixed ultrafine silicon powder is heated to 106°C and vacuum distilled while stirring. When the solvent volume is reduced to one third, stirring is stopped and vacuum distillation is performed directly to recover the solvent.

[0060] In this embodiment, a modified solvent recovery device is used to recover the solvent. Referring to Figure 1, the modified solvent recovery device includes a reactor 8, a temperature control probe 1, a mechanical stirrer 2, a clamp 3, a heating package 4, a dry ice basin 5, a condenser 6 and a cold hydrazine 7. The temperature control probe 1, the mechanical stirrer 2 and the clamp 3 are arranged on the reactor 8, the heating package 4 is arranged at the bottom of the reactor 8, the two ends of the condenser 6 are respectively connected to the reactor 8 and the dry ice basin 5, and the cold hydrazine 7 is also connected to the condenser 6 and the dry ice basin 5.

[0061] The reactor 8 is used to provide a reaction space; the mechanical stirrer 2 is used for stirring and dispersing; the temperature control probe 1 is used to detect the reaction temperature; the clamp 3 is used to lock the reactor 8 to ensure the vacuum degree inside the reactor 8; the heating pack 4 is used to achieve uniform heating of the bottom of the reactor 8; the dry ice basin 5 is used to create a temperature difference to guide the solvent gas from the high-temperature area of ​​the reactor 8 to the low-temperature area of ​​the dry ice basin 5; the condenser 6 is used to condense the solvent gas into a liquid and enter the dry ice basin 5; the cold hydrazine 7 is used to control gas escape and protect the vacuum pump.

[0062] 1, the specific process of using the modified solvent recovery device to recover the solvent is as follows:

[0063] Ultrafine silicon powder and solvent are dispersed and reacted in the reactor 8 under the action of the mechanical stirrer 2. As the temperature in the reactor 8 rises, the vaporized solvent enters the condenser 6 due to the temperature difference. The condenser 6 condenses the solvent gas into liquid and enters the dry ice basin 5 to achieve solvent recovery.

[0064] When the solvent volume is further reduced to one third, the bottom of the ultrafine silicon powder solution is evenly heated by the heating pack 4, stirring is stopped, and vacuum distillation is directly performed until the remaining solvent enters the dry ice basin 5.

[0065] S5: Drying into powder:

[0066] The modified silicon micropowder mixture after solvent distillation and recovery was placed in a 180° C. forced air oven for 2 hours to obtain modified silicon micropowder.

[0067] The present invention aims to enhance the hydrophobicity of the surface of silicon micropowder. Hexafluoropropylene trimer is selected to dissolve the modifier, so that the long fatty chain of the modifier is stretched in the hexafluoropropylene trimer and then grafted onto the hydroxyl group of the silicon micropowder, thereby enhancing the hydrophobicity of the silicon micropowder and the steric hindrance effect between particles, thereby improving the modification effect on the surface of the silicon micropowder.

[0068] Example 3:

[0069] This embodiment provides a method for modifying ultrafine silicon powder with a solvent recovery function, comprising the following steps:

[0070] S1: Modified resin dissolution:

[0071] The modified resin is a fluorine-containing resin. In this embodiment, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer is selected. The tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer is dissolved in a hexafluoropropylene trimer solvent at a ratio of 6‰. The dissolution temperature is 60°C and the dissolution time is 6 hours to obtain a modified resin solvent.

[0072] S2: Weigh 200 parts of a modified resin solvent, mix it with 400 parts of a hexafluoropropylene trimer solvent, and stir thoroughly to obtain a mixed solvent;

[0073] S3: Silica powder dispersion:

[0074] 200 parts of ultrafine silicon powder were added to the mixed solvent, and the mixture was added while stirring. After the addition was completed, the temperature was raised and controlled at 100°C, the stirring speed was 800 r / min, and the dispersion time was 1 hour;

[0075] S4: Recover the solvent by vacuum distillation:

[0076] The mixed ultrafine silicon powder is heated to 112°C and vacuum distilled while stirring. When the solvent volume is reduced to one third, stirring is stopped and vacuum distillation is performed directly to recover the solvent.

[0077] In this embodiment, a modified solvent recovery device is used to recover the solvent. Referring to Figure 1, the modified solvent recovery device includes a reactor 8, a temperature control probe 1, a mechanical stirrer 2, a clamp 3, a heating package 4, a dry ice basin 5, a condenser 6 and a cold hydrazine 7. The temperature control probe 1, the mechanical stirrer 2 and the clamp 3 are arranged on the reactor 8, the heating package 4 is arranged at the bottom of the reactor 8, the two ends of the condenser 6 are respectively connected to the reactor 8 and the dry ice basin 5, and the cold hydrazine 7 is also connected to the condenser 6 and the dry ice basin 5.

[0078] The reactor 8 is used to provide a reaction space; the mechanical stirrer 2 is used for stirring and dispersing; the temperature control probe 1 is used to detect the reaction temperature; the clamp 3 is used to lock the reactor 8 to ensure the vacuum degree inside the reactor 8; the heating pack 4 is used to achieve uniform heating of the bottom of the reactor 8; the dry ice basin 5 is used to create a temperature difference to guide the solvent gas from the high-temperature area of ​​the reactor 8 to the low-temperature area of ​​the dry ice basin 5; the condenser 6 is used to condense the solvent gas into a liquid and enter the dry ice basin 5; the cold hydrazine 7 is used to control gas escape and protect the vacuum pump.

[0079] 1, the specific process of using the modified solvent recovery device to recover the solvent is as follows:

[0080] Ultrafine silicon powder and solvent are dispersed and reacted in the reactor 8 under the action of the mechanical stirrer 2. As the temperature in the reactor 8 rises, the vaporized solvent enters the condenser 6 due to the temperature difference. The condenser 6 condenses the solvent gas into liquid and enters the dry ice basin 5 to achieve solvent recovery.

[0081] When the solvent volume is further reduced to one third, the bottom of the ultrafine silicon powder solution is evenly heated by the heating pack 4, stirring is stopped, and vacuum distillation is directly performed until the remaining solvent enters the dry ice basin 5.

[0082] S5: Drying into powder:

[0083] The modified silicon micropowder mixture after solvent distillation and recovery was placed in a 180° C. forced air oven for 2 hours to obtain modified silicon micropowder.

[0084] The present invention aims to enhance the hydrophobicity of the surface of silicon micropowder. Hexafluoropropylene trimer is selected to dissolve the modifier, so that the long fatty chain of the modifier is stretched in the hexafluoropropylene trimer and then grafted onto the hydroxyl group of the silicon micropowder, thereby enhancing the hydrophobicity of the silicon micropowder and the steric hindrance effect between particles, thereby improving the modification effect on the surface of the silicon micropowder.

[0085] Comparative Example 1:

[0086] In order to verify the actual effect of the method of the present invention, the methods of Examples 1 to 3 were experimentally compared and analyzed with the existing silicon powder modification method in this example. The specific performance data are as follows:

[0087] Table 1

[0088] Note: The hydrophobicity of silicon micropowder is determined by dropping water on the surface of the material and observing the contact angle. The larger the contact angle, the better the hydrophobicity.

[0089] It can be seen from the above comparative data that, compared with the existing silicon micropowder modification method, the improved method of Examples 1 to 3 not only consumes less solvent, but also can achieve efficient solvent recovery and has an extremely high solvent recovery rate. The recovered solvent can be reused in the silicon micropowder modification, thereby effectively reducing the overall cost of the silicon micropowder modification process. More importantly, the modification effect on silicon micropowder is also better than the existing silicon micropowder modification method.

Claims

1. A method for modifying ultrafine silicon powder with solvent recovery function, characterized in that: The steps include: S1: dissolving the modified resin in a solvent of hexafluoropropylene trimer; S2: weighing a specified amount of the modified resin solvent of step S1, mixing it with a specified amount of hexafluoropropylene trimer solvent, and then stirring; S3: adding the ultrafine silicon powder into the mixed solvent of step S2 to perform silicon powder dispersion reaction; S4: recovering the solvent by vacuum distillation; S5: drying the modified silicon micropowder mixture after the solvent is distilled and recovered to obtain modified silicon micropowder.

2. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 1, characterized in that: In the step S1, the ratio of the modified resin in the solvent is 4-6‰, the dissolution temperature is 50-60°C, and the dissolution time is 1-6 hours.

3. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 1, characterized in that: In the step S2, the mass ratio of the modified resin solvent to the solvent is 1:

2.

4. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 1, characterized in that: In step S1, the modified resin is a fluorine-containing resin, selected from any one or a combination of at least two of polytetrafluoroethylene, perfluorosulfonic acid resin, perfluorocarboxylic acid resin, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, perfluoro-2,5-dimethyl-3,6-dioxanoic acid, perfluoro-2,5-dimethyl-3,6-dioxaheptanoic acid, 2-(perfluoropropoxy)perfluoropropyl trifluorovinyl ether, perfluorosilane coupling agent, (3,3,3-trifluoropropyl)trimethoxysilane, heptadecafluorodecyltrimethoxysilane; 5. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 1, characterized in that: The operation flow of the silicon micropowder dispersion reaction in step S3 is as follows: ultrafine silicon micropowder is added into a mixed solvent, and the mixture is added while stirring, and the temperature is raised after the addition of the mixture is completed to perform a dispersion reaction.

6. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 5, characterized in that: In the silicon powder dispersion reaction, after the feeding is completed, the temperature is controlled at 80-100° C., the stirring speed is 500-800 r / min, and the dispersion time is 1 hour.

7. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 1, characterized in that: The step S4 specifically comprises: continuing to heat the uniformly mixed ultrafine silicon powder, performing vacuum distillation while stirring, and stopping stirring when the volume of the solvent is further reduced to one third of the remaining volume, performing direct vacuum distillation, and recovering the solvent.

8. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 6, characterized in that: In the step S4, the temperature of the uniformly mixed ultrafine silicon powder is further raised to 106-112°C.

9. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 7, characterized in that: In the step S4, a modified solvent recovery device is used to recover the solvent, and the modified solvent recovery device includes a reaction kettle, a temperature control probe, a mechanical stirrer, a clamp, a heating bag, a dry ice basin, a condenser and a cold hydrazine; The reactor is used to provide a reaction space; the mechanical stirrer is used for stirring and dispersing; the temperature control probe is used to detect the reaction temperature; the clamp is used to lock the reactor to ensure the vacuum degree in the reactor; the heating pack is used to achieve uniform heating of the bottom of the reactor; the dry ice basin is used to create a temperature difference to guide the solvent gas from the high-temperature area of ​​the reactor to the low-temperature area of ​​the dry ice basin; the condenser is used to condense the solvent gas into a liquid state and enter the dry ice basin; the cold hydrazine is used to control gas escape and protect the vacuum pump.

10. The method for modifying ultrafine silicon powder with solvent recovery function according to claim 9, characterized in that: The specific process of using the modified solvent recovery device to recover the solvent in step S4 is: Ultrafine silicon powder and solvent are dispersed and reacted in the reactor under the action of a mechanical stirrer. As the temperature in the reactor rises, the vaporized solvent enters the condenser due to the temperature difference. The condenser condenses the solvent gas into liquid and enters the dry ice basin to achieve solvent recovery. When the solvent is further reduced to one third of the volume, the bottom of the ultrafine silicon powder solution is evenly heated by a heating pack, stirring is stopped, and vacuum distillation is directly performed until the remaining solvent enters the dry ice basin.

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