Processing system and processing method for waste liquid containing silicon particles

Abstract

This invention discloses a treatment system and method for waste liquid containing silicon particles. The treatment system includes: a waste liquid unit, a tubular membrane filtration unit, a drying unit, a calcination unit, and a collection unit. The waste liquid unit collects process waste liquid containing water and silicon particles. The tubular membrane filtration unit filters the process waste liquid and increases the concentration of silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrated liquid containing silicon particles. The drying unit further dries the concentrated liquid to obtain dried silicon particles. The calcination unit calcines the dried silicon particles in a nitrogen-filled environment, causing the silicon particles to react with nitrogen to produce silicon nitride powder material, which is then collected by the collection unit.

Description

Technical Field

[0001] The present invention relates to a treatment system and a treatment method for waste liquid containing silicon particles, and in particular to a treatment system and a treatment method for waste liquid containing silicon particles used to produce silicon nitride powder material. Prior Art

[0002] During the backside grinding process, the backside of a silicon wafer is typically ground to the desired thickness. Conventional treatment methods typically add large amounts of chemicals to the wastewater generated at the end of the process, converting it into sludge for disposal. However, large amounts of sludge can increase the subsequent processing load and place a burden on the environment. Furthermore, the sludge itself lacks industrial application value.

[0003] Therefore, the inventors believe that the above-mentioned defects can be improved, and have devoted themselves to research and applied scientific principles to finally propose the present invention which has a reasonable design and effectively improves the above-mentioned defects. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a treatment system and a treatment method for waste liquid containing silicon particles in response to the deficiencies of the prior art.

[0005] To solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is to provide a treatment system for waste liquid containing silicon particles, comprising: a waste liquid unit, which is used to collect a process waste liquid, wherein the process waste liquid contains water and silicon particles dispersed in the water; a tubular membrane filtration unit, which comprises: a tubular membrane, which is used to filter the process waste liquid and increase the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrated liquid containing the silicon particles; and a tubular casing, which is arranged on the outside of the tubular membrane and is used to output the concentrated liquid; a drying unit, which is configured to further dry the concentrated liquid to obtain the dried silicon particles; a calcination unit, which is configured to calcine the dried silicon particles in an environment filled with nitrogen, so that the silicon particles react with the nitrogen to produce a silicon nitride powder material; and a collection unit, which is used to collect the silicon nitride powder material.

[0006] Preferably, the tubular casing has: a feed port located at one end of the tubular membrane, for conveying the process waste liquid into the tubular membrane; a clean water outlet located at the side of the tubular membrane, for discharging water or small molecules in the process waste liquid; and a product outlet located at the other end of the tubular membrane, for outputting the concentrated liquid.

[0007] Preferably, the tubular membrane filtration unit further comprises a reflux line connected to the product outlet of the tubular casing, for returning the process waste liquid that does not reach the predetermined concentration to the waste liquid unit or the feed inlet, so that the process waste liquid is filtered again, thereby increasing the concentration of the silicon particles in the process waste liquid to the predetermined concentration, and outputting the concentrated liquid from the product outlet.

[0008] Preferably, the silicon particles are solid particles produced by grinding silicon wafers.

[0009] Preferably, the silicon particles in the process waste liquid have an initial concentration between 0.001 wt % and 0.5 wt %.

[0010] Preferably, the process waste liquid is filtered through the tubular membrane filtration unit, and the predetermined concentration of the silicon particles in the concentrated liquid is not less than 1 wt%.

[0011] Preferably, the water content of the dried silicon particles is not greater than 5 wt%.

[0012] Preferably, the calcination unit calcines the dried silicon particles at a temperature between 1000° C. and 1700° C., with the optimum temperature being between 1200° C. and 1400° C.

[0013] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a method for treating waste liquid containing silicon particles, comprising: inputting a process waste liquid into a tubular membrane filtration unit for filtration; wherein the process waste liquid contains water and silicon particles dispersed in the water; allowing the process waste liquid to reflux in the tubular membrane filtration unit to increase the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrated liquid containing the silicon particles; using a drying unit to further remove water from the concentrated liquid and obtain dried silicon particles; and using a calcining unit to calcine the dried silicon particles in an environment filled with nitrogen, so that the dried silicon particles react with the nitrogen to form a silicon nitride powder material.

[0014] Preferably, when the dried silicon particles are calcined in an environment filled with nitrogen, a carbon source may be added so that part of the dried silicon particles react with the carbon source to form a silicon carbide powder material.

[0015] The beneficial effect of the present invention lies in that the present invention provides a treatment system and treatment method for waste liquid containing silicon particles, which can be achieved through "a waste liquid unit for collecting a process waste liquid, wherein the process waste liquid contains water and silicon particles dispersed in the water" and "a tubular membrane filtration unit, which comprises: a tubular membrane for filtering the process waste liquid and increasing the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrated liquid containing the silicon particles; and a tubular casing, which is sleeved on the outside of the tubular membrane, The present invention relates to a technical solution comprising a device for outputting the concentrated liquid, a drying unit configured to further dry the concentrated liquid to obtain dried silicon particles, a calcining unit configured to calcine the dried silicon particles in a nitrogen-filled environment so that the dried silicon particles react with the nitrogen to produce a silicon nitride powder material, and a collection unit for collecting the silicon nitride powder material, so that process waste liquid can be properly treated, thereby solving the problems of increased subsequent treatment load and environmental burden.

[0016] Furthermore, the process waste liquid can be converted into a recycled product (silicon nitride powder material) with industrial application value through the treatment system provided by the present invention. For example, the recycled product (silicon nitride powder material) with industrial application value can be used as a heat-resistant material, electronic material, and thermal conductive material, etc.

[0017] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, such description and drawings are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. Simple diagram description

[0018] FIG1 is a system block diagram of a processing system according to a first embodiment of the present invention.

[0019] FIG2 is a system block diagram of a processing system according to a second embodiment of the present invention.

[0020] FIG3 is a system block diagram of a processing system according to a third embodiment of the present invention.

[0021] FIG4 is a schematic diagram of a tubular membrane filtration unit of the present invention.

[0022] FIG5 is a flow chart of a method for treating waste liquid containing silicon particles according to the present invention. Implementation Method

[0023] The following is a description of the implementation of the "system for treating waste liquid containing silicon particles and its treatment method" disclosed in the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple schematic illustrations and are not depicted in actual size. Please note that the following embodiments will further explain the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0024] It should be understood that while terms such as "first," "second," and "third" may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein may include any one or more combinations of the associated listed items, as appropriate.

[0025] [First embodiment]

[0026] Please refer to Figures 1 and 4 , which illustrate a first embodiment of the present invention. This embodiment discloses a system 100A for treating waste liquid containing silicon particles, comprising: a waste liquid unit 1, a tubular membrane filtration unit 2, a drying unit 3, a calcination unit 4, and a collection unit 5. The waste liquid unit 1 is used to collect process waste liquid S1. The process waste liquid S1 comprises water and silicon particles S11 dispersed in the water.

[0027] In one embodiment of the present invention, the process waste liquid S1 may be, for example, waste liquid generated by a wafer backside grinding process, but the present invention is not limited thereto. The process waste liquid may also be, for example, waste liquid generated by other processes.

[0028] Specifically, during the backside grinding process, the backside of a silicon wafer is typically ground to achieve a desired thickness, generating a process waste liquid S1 after the process is completed. Specifically, the process waste liquid S1 comprises water and silicon particles S11 dispersed in the water. The silicon particles S11 are solid particles generated after the silicon wafer is ground, and have an initial concentration in the process waste liquid S1 of between 0.001 wt% and 0.5 wt%.

[0029] More specifically, in this embodiment, the silicon particles S11 may be, for example, silicon dioxide particles, but the present invention is not limited thereto.

[0030] Generally speaking, in conventional techniques for treating process wastewater S1, a large amount of chemicals is typically added to the wastewater S1, which is then converted into sludge for disposal. However, large amounts of sludge can increase the subsequent treatment load and place a burden on the environment.

[0031] To address this problem, the present invention provides a system 100A for treating waste liquid containing silicon particles. This system can properly treat the process waste liquid S1 and produce a product with industrial application value. To achieve this objective, the following describes the technical solution to this problem.

[0032] The waste liquid unit 1 is used to collect the process waste liquid S1 generated by the wafer back grinding process. The waste liquid unit 1 can be, for example, a collection tank, but the present invention is not limited thereto.

[0033] The waste liquid unit 1 collects the process waste liquid S1 and then transports the process waste liquid S1 to the tubular membrane filtration unit 2. The tubular membrane filtration unit 2 is configured to filter and purify the process waste liquid S1, so that water or small molecules in the process waste liquid S1 are discharged through the side of the tubular membrane filtration unit 2.

[0034] On the other hand, the tubular membrane filtration unit 2 is configured to filter and purify the process waste liquid S1 to increase the concentration of the silicon particles S11 in the process waste liquid S1 to a predetermined concentration.

[0035] More specifically, as shown in FIG. 4 , the tubular membrane filtration unit 2 includes a tubular membrane 21 and a tubular casing 22 sleeved on the outside of the tubular membrane 21 .

[0036] Furthermore, the tubular membrane filtration unit 2 is used to filter and purify the process waste liquid S1 through the tubular membrane 21, thereby increasing the concentration of the silicon particles S11 in the process waste liquid S1 to reach the predetermined concentration, thereby forming a concentrated liquid S2 containing the silicon particles S11.

[0037] Furthermore, in this embodiment, the tubular membrane 21 is a polymer tubular filtration membrane, and its pore size can be an ultrafiltration (0.1μm-0.001μm) module. More specifically, ultrafiltration is a pressurized membrane separation technology that, under a certain pressure, allows small molecular solutes and solvents to pass through a specially designed membrane with a certain pore size, while preventing large molecular solutes (i.e., the sand particles S11) from passing through and remaining on one side of the membrane, thereby partially purifying the large molecules.

[0038] The tubular membrane 21 further includes, from the inside out, a filter membrane layer 211, an inner support tube 212, and an outer support tube 213, but the present invention is not limited thereto.

[0039] Furthermore, in this embodiment, the filter membrane layer 211 may be a polymer coating, such as polystyrene (PS), polyethylene (PE), polyvinylidene fluoride (PVDF), polyether sulfide (PES), polytetrafluoroethylene (PTFE), or a combination thereof, but the present invention is not limited thereto. Furthermore, in this embodiment, the inner support tube 212 and the outer support tube 213 may be made of PET or PP non-woven fabric, but the present invention is not limited thereto; any other material with sufficient permeability and strength may also be used.

[0040] The tubular membrane 21 is configured to filter and purify the process waste liquid S1 to form the concentrated liquid S2 which is further output through the tubular casing 22 .

[0041] The tubular casing 22 has a feed inlet 221 located at one end of the tubular membrane 21 (such as the left end in FIG4 ), a clean water outlet 222 located at the side of the tubular membrane 21 , and a product outlet 223 located at the other end of the tubular membrane 21 (such as the right end in FIG4 ).

[0042] Specifically, the feed port 221 is used to transport the process waste liquid S1 into the tubular membrane 21, and then discharge the water or small molecular substances in the process waste liquid S1 through the clean water outlet 222, and output the concentrated liquid S2 through the product outlet 223.

[0043] More specifically, in this embodiment, the tubular casing 22 can be, for example, a metal outer tube or a plastic outer tube made of a polymer material such as polyvinyl chloride (PVC) or polypropylene (PP), but the present invention is not limited thereto.

[0044] In more detail, the concentrated liquid S2 is produced by filtration and purification of the tubular membrane filtration unit 2 in this embodiment, so that the predetermined concentration of the silicon particles S11 in the concentrated liquid S2 reaches a concentration of not less than 1 wt%, and preferably not less than 20 wt%.

[0045] As described above, in order to make the silicon particles S11 in the concentrated liquid S2 reach the predetermined concentration, the tubular membrane filtration unit 2 further includes a reflux line 224. The reflux line 224 is connected to the product outlet 223 of the tubular casing 22, and is used to reflux the process waste liquid S1 that does not reach the predetermined concentration to the waste liquid unit 1 or the feed inlet 221, so that the process waste liquid S1 is filtered and purified again, thereby increasing the concentration of the silicon particles S11 in the process waste liquid S1 to the predetermined concentration, and finally outputting the concentrated liquid S2 from the product outlet 223.

[0046] Continuing to refer to FIG. 1 , the concentrated liquid S2 is output from the tubular membrane filtration unit 2 and enters the drying unit 3 . The drying unit 3 is configured to further dry the concentrated liquid S2 to obtain dried silicon particles S3 , wherein the water content of the dried silicon particles S3 is no greater than 5 wt %.

[0047] In some embodiments of the present invention, the drying unit 3 may dry the concentrated liquid S2 by, for example, a drying machine, a rotary dryer, a flash dryer, or a vibration dryer, but the present invention is not limited thereto.

[0048] The calcination unit 4 is configured in an environment filled with nitrogen G to calcine the dried silicon particles S3, so that the dried silicon particles S3 react with the nitrogen G to generate a silicon nitride powder material S4.

[0049] Specifically, the calcination unit 4 calcines the dried silicon particles S3 at a temperature between 1000° C. and 1700° C., with the optimal temperature being between 1200° C. and 1400° C. In this embodiment, the calcination unit 4 may be, for example, a calcination furnace for calcination, but the present invention is not limited thereto.

[0050] After the dried silicon particles S3 are calcined by the calcining unit 4, the collecting unit 5 is used to collect the silicon nitride powder material S4. Furthermore, in this embodiment, the collecting unit 5 can be, for example, a collecting tank or a collecting tank, but the present invention is not limited thereto.

[0051] According to the above configuration, the process waste liquid S1 can be properly treated by the treatment system 100A provided by the embodiment of the present invention, thereby solving the problem that a large amount of sludge may cause an increase in the subsequent treatment load and a burden on the environment.

[0052] Furthermore, through the treatment system 100A provided in this embodiment of the present invention, the process waste liquid S1 can be treated to produce the silicon nitride powder material S4, which has industrial application value. The silicon nitride powder material S4 has the following material properties, such as high hardness and mechanical strength, low thermal expansion coefficient, good oxidation resistance, corrosion resistance, and high fracture toughness. It can be widely used in precision machinery, metallurgy, aerospace, chemical engineering, biomedicine, and other fields. For example, the silicon nitride powder material S4 can be used as a heat-resistant material, electronic material, and thermal conductive material. Its application products can also include cutting tools, ceramic bearings, refractory materials, and high-temperature engine nozzles, but the present invention is not limited to this.

[0053] [Second embodiment]

[0054] Please refer to Figures 2 and 4 , which illustrate a second embodiment of the present invention. This embodiment discloses a system 100B for treating wastewater containing silicon particles. Since this embodiment is similar to the first embodiment, the similarities between the two embodiments will not be described in detail. The differences between this embodiment and the first embodiment are briefly described as follows:

[0055] In this embodiment, when the dried silicon particles S3 are calcined in an environment filled with nitrogen G, a carbon source C may be added so that part of the dried silicon particles S3 can react with the carbon source C to form a silicon carbide powder material S4a.

[0056] According to the above configuration, the process waste liquid S1 can be properly treated through the treatment system 100B provided by the embodiment of the present invention, thereby solving the problem that a large amount of sludge may cause an increase in the subsequent treatment load and a burden on the environment.

[0057] Furthermore, through the treatment system 100B provided in this embodiment of the present invention, the process waste liquid S1 can be further processed to produce the silicon carbide powder material S4a, which has industrial application value. The silicon carbide powder material S4a has high thermal conductivity and possesses better hardness, heat resistance, oxidation resistance, corrosion resistance, and high thermal conductivity than conventional ceramic materials. It can be widely used in structural parts in mechanical engineering and seals in chemical engineering. For example, the silicon carbide powder material S4a can be used as automotive parts, heat-resistant parts for high-temperature electric furnaces and other electric heating applications, or in equipment materials such as bearings, cutting tools, heat-dissipating ceramic structural materials, and deoxidizer materials, but the present invention is not limited to these.

[0058] [Third embodiment]

[0059] Please refer to Figures 3 and 4 , which illustrate a third embodiment of the present invention. This embodiment discloses a system 100C for treating wastewater containing silicon particles. Since this embodiment is similar to the second embodiment described above, the similarities between the two embodiments will not be further described. The differences between this embodiment and the second embodiment described above are briefly described as follows:

[0060] In this embodiment, the number of tubular membrane filtration units 2 can be multiple. More specifically, the multiple tubular membrane filtration units 2 are arranged side by side and connected in series. According to this configuration, compared to a single tubular membrane filtration unit 2, multiple tubular membrane filtration units 2 can improve the concentration efficiency of the process waste liquid S1, reduce the number of refluxes, and maintain a higher flow rate. This allows the treatment system 100C provided by this embodiment of the present invention to further improve the filtration and purification efficiency and extend the service life of the tubular membranes 21 in the tubular membrane filtration units 2.

[0061] [Treatment Method for Wastewater Containing Silicon Particles]

[0062] Another embodiment of the present invention also provides a method for treating waste liquid containing silicon particles, as shown in FIG5 . The method includes steps S100 to S130. It should be noted that the order of the steps and the actual operation methods described in this embodiment can be adjusted as needed and are not limited to those described in this embodiment.

[0063] The step S100 includes: inputting a process waste liquid S1 generated by the wafer backside grinding process into a tubular membrane filtration unit 2 for filtration and purification. The process waste liquid includes water and silicon particles S11 dispersed in the water.

[0064] The step S110 includes: refluxing the process waste liquid S1 in the tubular membrane filtration unit 2 to increase the concentration of the silicon particles S11 in the process waste liquid S1 to a predetermined concentration, thereby forming a concentrated liquid S2 containing the silicon particles S11.

[0065] Furthermore, the predetermined concentration of the silicon particles in the concentrated solution is not less than 1 wt %, and preferably not less than 20 wt %.

[0066] The step S120 includes: using a drying unit 3 to further remove water from the concentrated liquid S2 and obtain dried silicon particles S3.

[0067] The step S130 includes: using a calcination unit 4 to calcine the dried silicon particles S3 in an environment filled with nitrogen G (the calcination temperature is between 1000°C and 1700°C, and the optimal temperature is between 1200°C and 1400°C), so that the dried silicon particles S3 react with the nitrogen G to form a silicon nitride powder material S4.

[0068] Furthermore, the process waste liquid S1 can also be formed into a silicon carbide powder material S4a through the treatment method provided by the embodiment of the present invention.

[0069] In one embodiment, when the dried silicon particles S3 are calcined in an environment filled with nitrogen G, a carbon source C may be added so that a portion of the dried silicon particles S3 reacts with the carbon source C to form the silicon carbide powder material S4a.

[0070] [Technical Effects of the Embodiments of the Invention]

[0071] The beneficial effect of the present invention is that the present invention provides a treatment system and treatment method for waste liquid containing silicon particles, which can be achieved through "a waste liquid unit, which is used to collect a process waste liquid, wherein the process waste liquid contains water and silicon particles dispersed in the water" and "a tubular membrane filtration unit, which includes: a tubular membrane, which is used to filter the process waste liquid and increase the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrated liquid containing the silicon particles; and a tubular casing, which is set on the outside of the tubular membrane, which is used to filter the process waste liquid. The present invention provides a technical solution comprising a device for outputting the concentrated liquid, a drying unit configured to further dry the concentrated liquid to obtain the dried silicon particles, a calcining unit configured to calcine the dried silicon particles in a nitrogen-filled environment, so that the silicon particles react with the nitrogen to produce a silicon nitride powder material, and a collecting unit for collecting the silicon nitride powder material, so that the process waste liquid generated by the process can be properly treated, thereby solving the problems of increased subsequent treatment load and burden on the environment. Furthermore, the process waste liquid can be converted into a recycled product (silicon nitride powder material) with industrial application value through the treatment system provided by the present invention. For example, the recycled product (silicon nitride powder material) with industrial application value can be used as a heat-resistant material, an electronic material, and a thermal conductive material.

[0072] The contents disclosed above are only preferred feasible embodiments of the present invention and do not limit the patent scope of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention's description and drawings are included in the patent scope of the present invention.

[0073] 100A, 100B, 100C: Treatment system for waste liquid containing silicon particles 1: Waste liquid unit 2: Tubular membrane filtration unit 21: Tubular membrane 211: Filter membrane layer 212: Inner support tube 213: Outer support tube 22: Tubular housing 221: Feeding port 222: Clean water outlet 223: Product Export 224: Return line 3: Drying unit 4: Calcination unit 5: Collection unit S1: Process wastewater S11: Silicon particles S2: Concentrate S3: Dried silicon particles S4: Silicon nitride powder material S4a: Silicon carbide powder material G: Nitrogen C: Carbon source S100, S110, S120, S130: Steps

Claims

1. A treatment system for waste liquid containing silica particles, comprising: A waste liquid unit for collecting a process waste liquid, wherein the process waste liquid contains water and silicon particles dispersed in the water; a tubular membrane filtration unit comprising: a tubular membrane for filtering and purifying the process waste liquid, and increasing the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrate containing the silicon particles; and a tubular casing fitted over the outside of the tubular membrane for discharging the concentrate, the tubular casing having: an inlet located at one end of the tubular membrane along a length direction for conveying the process waste liquid into the tubular membrane; A purified water outlet, located on the side of the tubular membrane along a direction perpendicular to the length direction, is used to discharge water or small molecule substances from the process waste liquid; and a product outlet, located at the other end of the tubular membrane along the length direction, is used to output the concentrate; and a return pipeline, connected to the product outlet of the tubular casing, is used to return the process waste liquid that has not reached the predetermined concentration to the waste liquid unit or the feed inlet, so as to filter the process waste liquid again, thereby increasing the concentration of silicon particles in the process waste liquid to the predetermined concentration, so that the concentrate can be output from the product outlet; wherein the predetermined concentration of silicon particles in the concentrate is not less than 20 wt%; and a drying unit, configured to further dry the concentrate to obtain dried silicon particles; A calcination unit configured in a nitrogen-filled environment to calcine the dried silicon particles, causing the dried silicon particles to react with nitrogen to produce a silicon nitride powder material; and a collection unit for collecting the silicon nitride powder material.

2. The waste liquid treatment system containing silica particles as described in claim 1, wherein, The silicon particles are solid particles produced by grinding silicon wafers.

3. The waste liquid treatment system containing silica particles as described in claim 2, wherein, The silicon particles in the process waste liquid have an initial concentration between 0.001 wt% and 0.5 wt%.

4. The waste liquid treatment system containing silica particles as described in claim 1, wherein, The moisture content of the dried silicon particles is no more than 5 wt%.

5. The waste liquid treatment system containing silica particles as described in claim 1, wherein, The calcination temperature of the calcination unit for the dried silicon particles is between 1000℃ and 1700℃.

6. A method for treating waste liquid containing silica particles, comprising: A process waste liquid is fed into a tubular membrane filtration unit for filtration; wherein the process waste liquid contains water and silicon particles dispersed in the water; the process waste liquid is then refluxed into the tubular membrane filtration unit to increase the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrate containing the silicon particles; wherein the tubular membrane filtration unit comprises: a tubular membrane for filtering and purifying the process waste liquid, and increasing the concentration of the silicon particles in the process waste liquid to a predetermined concentration, thereby forming a concentrate containing the silicon particles; and a tubular casing fitted over the outside of the tubular membrane for discharging the concentrate, the tubular casing having: an inlet located at one end of the tubular membrane along a length direction for conveying the process waste liquid into the tubular membrane. A purified water outlet, located on the side of the tubular membrane along a direction perpendicular to the length direction, is used to discharge water or small molecule substances from the process waste liquid; and a product outlet, located at the other end of the tubular membrane along the length direction, is used to output the concentrate; and a return pipeline, connected to the product outlet of the tubular casing, is used to return the process waste liquid that has not reached the predetermined concentration to the feed inlet, so as to filter the process waste liquid again, thereby increasing the concentration of silicon particles in the process waste liquid to the predetermined concentration, so as to output the concentrate from the product outlet; wherein the predetermined concentration of silicon particles in the concentrate is not less than 20 wt%; a drying unit further removes water from the concentrate and obtains dried silicon particles; and a calcination unit calcines the dried silicon particles in a nitrogen-filled environment, so that the silicon particles react with nitrogen to form a silicon nitride powder material.

7. The method for treating waste liquid containing silica particles as described in claim 6, wherein, When the dried silicon particles are calcined in a nitrogen-filled environment, a carbon source can be added to allow some of the dried silicon particles to react with the carbon source, thereby forming a silicon carbide powder material.

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