Polishing liquid recovery device and polishing liquid recovery method

Abstract

The invention relates to a grinding fluid recovery device which comprises an iron removal structure, a centrifugal structure and a filtering structure, the iron removal structure comprises a shell and a magnetic part, a first containing cavity used for containing waste liquid is formed in the shell, and at least one second containing cavity used for containing the magnetic part is further formed in the shell; the second containing cavity is independent of the first containing cavity, and at least one end of the second containing cavity penetrates through the corresponding side wall of the first containing cavity. The invention further relates to a grinding fluid recovery method. Through cooperation of the iron removal structure, the centrifugal structure and the filtering structure, used grinding fluid is treated and recycled, the utilization rate of the grinding fluid is increased, and the use amount of the grinding fluid is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor product manufacturing, and in particular to a grinding liquid recovery device and a grinding liquid recovery method. Background Art

[0002] In the silicon wafer grinding process, a large amount of grinding liquid is required. The grinding liquid is composed of grinding powder, dispersant, and water. After the new liquid is used once after the proportion is completed, less than 30% of the effective grinding powder particles in the grinding liquid are consumed. Directly using the waste liquid for re-grinding will cause problems such as excessive metal content in the silicon wafer, reduced grinding efficiency, and scratches on the silicon wafer surface. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a grinding liquid recovery device and a grinding liquid recovery method to solve the problem of low grinding liquid utilization rate.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted in the embodiment of the present invention is: a grinding liquid recovery device, including an iron removal structure, a centrifugal structure and a filtering structure:

[0005] The iron removal structure includes a shell and a magnetic part. A first accommodating cavity for accommodating waste liquid is arranged in the shell. At least one second accommodating cavity for accommodating the magnetic part is also arranged in the shell. The second accommodating cavity is arranged independently of the first accommodating cavity, and at least one end of the second accommodating cavity passes through the corresponding side wall of the first accommodating cavity.

[0006] Optionally, the magnetic part includes a magnetic rod and a moving structure, and the moving structure is used to control the second accommodating cavity to be inserted into or detached from the second accommodating cavity.

[0007] Optionally, the first accommodating cavity and the second accommodating cavity are an integral structure or a separate structure.

[0008] Optionally, the second accommodating cavity is a hollow cylindrical structure, and an axial direction of the second accommodating cavity is parallel to a first direction, and the first direction is a direction from the bottom of the shell to the top of the shell.

[0009] Optionally, a first waste liquid inlet is arranged at the top of the shell, a first waste liquid outlet is arranged at the bottom of the shell, and the second accommodating cavity is located between the first waste liquid inlet and the first waste liquid outlet.

[0010] Optionally, the shell includes a rectangular body, and the first waste liquid inlet and the second waste liquid outlet are located at diagonal positions of the shell.

[0011] Optionally, a cleaning liquid inlet is arranged at the top of the shell, and a cleaning liquid outlet is arranged at the bottom of the shell, the shell comprises a rectangular body, and the cleaning liquid inlet and the cleaning liquid outlet are located at diagonal positions of the shell.

[0012] Optionally, a centrifugal structure is also included to separate small waste particles in the waste liquid.

[0013] Optionally, the centrifugal structure is a cyclone-type centrifugal structure, including a funnel-shaped outer shell, and a rotating shaft located in the outer shell, and blades are arranged on the outer circumferential surface of the rotating shaft.

[0014] Optionally, it further includes a filtering structure, the filtering structure includes a third accommodating cavity, a third waste liquid inlet is arranged at the top of the third accommodating cavity, and a fourth waste liquid outlet is arranged at the bottom of the third accommodating cavity;

[0015] The filtering structure includes a filter screen and a collecting tray located inside the third accommodating cavity. The collecting tray is used to collect the grinding liquid filtered by the filter screen. A through hole is provided at the bottom of the collecting tray. The through hole is connected to a pipe, and the pipe is arranged through the side wall of the third accommodating cavity.

[0016] Optionally, the filtering structure further includes three gears distributed in a triangle, the three gears include a first gear and a second gear arranged near the second waste liquid inlet, and a line connecting the centers of the first gear and the second gear is perpendicular to the flow direction of the waste liquid entering from the second waste liquid inlet;

[0017] The filter screen is arranged around the three rotating wheels and rotates in a first plane driven by the three rotating wheels, wherein the first plane is parallel to the flow direction of the waste liquid entering from the second waste liquid inlet;

[0018] The collecting tray is located inside the filter screen and directly below a line connecting the centers of the first gear and the second gear.

[0019] Optionally, the three gears also include a third gear, and the filtering structure also includes a cleaning part for cleaning the filter mesh, the cleaning part includes a cleaning nozzle located inside a triangle formed by the three gears, the cleaning nozzle sprays cleaning liquid toward a portion of the filter mesh located between the second gear and the third gear, or the cleaning nozzle sprays cleaning liquid toward a portion of the filter mesh located between the first gear and the third gear.

[0020] The embodiment of the present invention further provides a grinding liquid recovery method, which uses the above-mentioned grinding liquid recovery device to recycle and reuse the grinding liquid. The grinding liquid recovery method comprises:

[0021] The iron chips in the waste grinding liquid are removed by the iron removal structure;

[0022] The small waste particles in the grinding liquid waste are removed by a centrifugal structure;

[0023] The impurities in the grinding liquid waste are further removed through the filtering structure.

[0024] Optionally, the step of removing iron filings from the waste grinding liquid by the iron removal structure specifically includes:

[0025] Inserting the magnetic rod into the second accommodating cavity, so that the iron filings in the waste liquid entering the first accommodating cavity are adsorbed onto the outer wall of the second accommodating cavity;

[0026] The magnetic rod is taken out from the second accommodating cavity, and a cleaning liquid is introduced into the first accommodating cavity to clean the outer walls of the first accommodating cavity and the second accommodating cavity.

[0027] The beneficial effects of the present invention are as follows: through the coordination of the iron removal structure, the centrifugal structure and the filtering structure, the used grinding liquid is processed and recycled, the utilization rate of the grinding liquid is improved, and the amount of grinding liquid used is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram showing an iron removal structure in an embodiment of the present invention;

[0029] Figure 2 A schematic diagram showing an iron removal structure in an embodiment of the present invention;

[0030] Figure 3 A schematic diagram showing a centrifugal structure in the practice of the present invention;

[0031] Figure 4 A schematic diagram showing a filtering structure in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram showing the comparison of effective abrasive particles of initial polishing liquid, polishing liquid waste that has not been recycled, and polishing liquid after recycling. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0034] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0035] The features such as "parallel", "perpendicular", and "same" used in the embodiments of the present disclosure include the features such as "parallel", "perpendicular", and "same" in a strict sense, as well as the cases where "approximately parallel", "approximately perpendicular", "approximately the same", etc. include certain tolerances, taking into account the tolerances associated with the measurement of specific quantities (e.g., the limitations of the measurement system), and represent the acceptable deviation range for a specific value determined by ordinary technicians in the field. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of the value.

[0036] refer to Figure 1-Figure 4 , this embodiment provides a grinding liquid recovery device, including an iron removal structure, a centrifugal structure and a filtering structure:

[0037] The iron removal structure includes a shell 1 and a magnetic part. A first accommodating cavity 11 for accommodating waste liquid is arranged in the shell 1. At least one second accommodating cavity 12 for accommodating the magnetic part is also arranged in the shell 1. The second accommodating cavity 12 is arranged independently of the first accommodating cavity 11, and at least one end of the second accommodating cavity 12 passes through the corresponding side wall of the first accommodating cavity 11.

[0038] In this embodiment, the iron filings and other impurities that can be magnetically adsorbed are removed from the waste grinding liquid by the iron removal structure, the invalid small particles in the waste grinding liquid are separated by the centrifugal structure, and the impurities including large particles of silicon slag are filtered out by the filtering structure. The iron removal structure, the centrifugal structure and the filtering structure cooperate to process the used grinding liquid and recycle it, thereby improving the utilization rate of the grinding liquid and saving the amount of grinding liquid used.

[0039] refer to Figure 5 , Figure 5The blue curve represents the abrasive particle size curve of the initial polishing liquid, the yellow curve represents the abrasive particle size curve of the polishing liquid after recycling, and the gray curve represents the abrasive particle size curve of the polishing liquid waste that has not been recycled. Figure 5 It can be seen that the particle size distribution of the recycled grinding liquid is consistent with that of the initial grinding liquid (i.e., the new grinding liquid that has not been used), and the recovery ratio can reach about 70%, which greatly reduces the cost of using silicon wafer grinding consumables.

[0040] In an exemplary embodiment, the magnetic part includes a magnetic rod 2 and a moving structure 3 , and the moving structure 3 is used to control the second accommodating cavity 12 to be inserted into or detached from the second accommodating cavity 12 .

[0041] The magnetic rod 2 is inserted into the second accommodating cavity 12, and under the action of magnetic force, magnetic materials such as iron filings in the grinding liquid waste are adsorbed onto the outer wall of the second accommodating cavity 12. Figure 1 .

[0042] When the magnetic rod 2 is taken out of the second accommodating cavity 12, the magnetic force disappears. Figure 2 At this time, the cleaning fluid may be used to clean the first accommodating cavity 11 to remove the iron filings.

[0043] In an exemplary embodiment, the shells constituting the first accommodating cavity 11 and the second accommodating cavity 12 are made of non-magnetic material to prevent iron filings and other materials adsorbed on the first accommodating cavity 11 and the second accommodating cavity 12 from being difficult to remove. Exemplarily, the material constituting the shells of the first accommodating cavity 11 and the second accommodating cavity 12 can be made of PVC (polyvinyl chloride), but is not limited thereto.

[0044] In an exemplary embodiment, the first accommodating cavity 11 and the second accommodating cavity 12 are an integral structure or a separate structure.

[0045] The first accommodating cavity 11 and the second accommodating cavity 12 may be integrally injection molded. The first accommodating cavity 11 and the second accommodating cavity 12 may also be a split structure, that is, a through hole communicating with the first accommodating cavity 11 is provided on the side wall of the housing 1, and the second accommodating cavity 12 is inserted into the through hole.

[0046] Exemplarily, a hollow cylindrical retaining wall is arranged inside the first accommodating cavity 11 to form the second accommodating cavity 12 , and at least one end of the second accommodating cavity 12 passes through the corresponding side wall of the shell 1 to facilitate the insertion of the magnetic rod 2 .

[0047] In an exemplary embodiment, the second accommodating cavity 12 is a hollow cylindrical structure, and the axial direction of the second accommodating cavity 12 is parallel to the first direction, and the first direction is the direction from the bottom of the shell 1 to the top of the shell 1 (refer to Figure 2 in the X direction).

[0048] In an exemplary embodiment, a first waste liquid inlet 13 is disposed at the top of the shell 1 , a first waste liquid outlet 14 is disposed at the bottom of the shell 1 , and the second accommodating cavity 12 is located between the first waste liquid inlet 13 and the first waste liquid outlet 14 .

[0049] In an exemplary embodiment, the housing 1 includes a rectangular body, and the first waste liquid inlet 13 and the second waste liquid outlet 43 are located at diagonal positions of the housing 1 .

[0050] By adopting the above solution, the distance between the first waste liquid inlet 13 and the first waste liquid outlet 14 can be increased, so as to effectively remove magnetic substances such as iron filings in the waste grinding liquid.

[0051] It should be noted that the number of the second accommodating cavities 12 can be set according to actual needs, and the number of the magnetic bars 2 can be set according to actual needs. When the magnetic part includes a plurality of the magnetic bars 2, the magnetic part also includes a fixed plate, and the plurality of magnetic bars 2 are all fixed on the fixed plate. A moving rod is set on the side of the fixed plate where the magnetic bars 2 are not set. The moving structure controls the movement of the fixed plate through the moving rod, and then controls the synchronous movement of the plurality of magnetic bars 2 to improve efficiency.

[0052] In an exemplary embodiment, in order to effectively adsorb magnetic materials such as iron filings in the grinding liquid waste, the two opposite ends of the second accommodating cavity 12 respectively penetrate the corresponding side walls of the shell, that is, one end of the second accommodating cavity 12 penetrates the top of the shell, and the other end of the second accommodating cavity 12 penetrates the bottom of the shell. The length of the magnetic rod 2 is greater than the length of the second accommodating cavity. When the magnetic rod 2 is inserted into the second accommodating cavity 12, the magnetic rod 2 is exposed outside the second accommodating cavity.

[0053] In an exemplary embodiment, a cleaning liquid inlet 15 is disposed at the top of the shell 1 , and a cleaning liquid outlet 16 is disposed at the bottom of the shell 1 . The shell 1 includes a rectangular body, and the cleaning liquid inlet 15 and the cleaning liquid outlet 16 are located at diagonal positions of the shell 1 .

[0054] The arrangement of the cleaning liquid inlet 15 and the cleaning liquid outlet 16 facilitates the cleaning of the iron removal structure.

[0055] Exemplarily, the cleaning solution may include ultrapure water or the like.

[0056] In an exemplary embodiment, the grinding liquid recovery device further includes a centrifugal structure for separating small waste particles in the waste liquid.

[0057] In an exemplary embodiment, the centrifugal structure is a cyclone centrifugal structure, including a funnel-shaped outer shell, and a rotating shaft located in the outer shell, and blades are arranged on the outer circumferential surface of the rotating shaft. For details, reference may be made to the conventional structure of a cyclone centrifuge.

[0058] A second waste liquid inlet 42 is arranged on the side wall of the shell of the centrifugal structure, a second waste liquid outlet 43 is arranged on the top of the shell of the centrifugal structure, and a third waste liquid outlet 44 is arranged on the bottom of the shell of the centrifugal structure. Under the action of the centrifugal force, the low-density waste liquid rises and is discharged from the second waste liquid outlet 43, and the high-density waste liquid sinks and is discharged from the third waste liquid outlet 44 for further recovery treatment.

[0059] In an exemplary embodiment, the grinding liquid recovery device further includes a filtering structure, the filtering structure includes a third accommodating cavity 51, a third waste liquid inlet 57 is disposed at the top of the third accommodating cavity 51, and a fourth waste liquid outlet 58 is disposed at the bottom of the third accommodating cavity 51;

[0060] The filtering structure includes a filter screen 52 and a collecting tray located inside the third accommodating cavity 41. The collecting tray is used to collect the grinding liquid filtered by the filter screen 52. A through hole is opened at the bottom of the collecting tray. The through hole is connected to a pipe, and the pipe is set through the side wall of the third accommodating cavity 51.

[0061] In an exemplary embodiment, the filtering structure further includes three gears distributed in a triangle, the three gears including a first gear 54 and a second gear 55 disposed near the third waste liquid inlet 57, and a line connecting the centers of the first gear 54 and the second gear 55 is perpendicular to the flow direction of the waste liquid entering from the second waste liquid inlet 42;

[0062] The filter screen 52 is disposed around the three rotating wheels and rotates in a first plane driven by the three rotating wheels. The first plane is parallel to the flow direction of the waste liquid entering from the second waste liquid inlet 42.

[0063] The collecting tray is located inside the filter 52 , that is, inside a triangle formed by the first gear 54 , the second gear 55 and the third gear 56 , and directly below a line connecting the centers of the first gear 54 and the second gear 55 .

[0064] In an exemplary embodiment, the collecting tray includes a bottom wall and side walls located around the bottom wall to prevent the filtered grinding liquid from overflowing.

[0065] In an exemplary embodiment, the bottom wall is funnel-shaped to facilitate the filtered grinding liquid to flow out from the through hole located at the bottom of the collecting tray.

[0066] In an exemplary embodiment, the grinding liquid recovery device also includes a recovery structure for recovering the grinding liquid that has been processed sequentially by the iron removal structure, the centrifugal structure and the filtering structure, and the through hole at the bottom of the collection tray is connected to the recovery structure through a pipe.

[0067] In some embodiments, the three gears are distributed in an equilateral triangle, including a first gear 54, a second gear 55 and a third gear 56. The first gear 54 and the second gear 55 are arranged at the same height and are located near the third waste liquid inlet 57. The line connecting the centers of the first gear 54 and the second gear 55 is perpendicular to the flow direction of the waste liquid entering from the second waste liquid inlet 42, so that the grinding liquid waste entering the third accommodating cavity 41 flows vertically into the part of the filter net 52 located between the first gear 54 and the second gear 55 for easy filtration.

[0068] The filter screen 52 is arranged around the three gears and can rotate in the first plane driven by the three gears. The large particles of foreign matter remaining on the filter screen 52 will fall to the bottom of the third accommodating cavity 41 as the filter screen 52 rotates and be discharged from the fourth waste liquid outlet 58.

[0069] Exemplarily, the distance between the first gear 54 and the second gear 55 is greater than the length of the third waste liquid inlet 57 in the direction from the first gear 54 to the second gear 55, that is, the area of ​​the portion of the filter screen 52 located between the first gear 54 and the second gear 55 is greater than the area of ​​the positive projection of the third waste liquid inlet 57 on the filter screen 52, so that all the grinding liquid waste entering from the third waste liquid inlet 57 falls into the portion of the filter screen 52 located between the first gear 54 and the second gear 55 for effective filtration.

[0070] In an exemplary embodiment, the three gears also include a third gear 56, and the filtering structure also includes a cleaning part for cleaning the filter mesh 52, and the cleaning part includes a cleaning nozzle 59 located inside the triangle formed by the three gears, and the cleaning nozzle 59 sprays cleaning liquid toward the portion of the filter mesh 52 located between the second gear 55 and the third gear 56, or the cleaning nozzle 59 sprays cleaning liquid toward the portion of the filter mesh 52 located between the first gear 54 and the third gear 56.

[0071] The cleaning nozzle 59 can be provided to clean the part of the filter screen 52 that is not performing filtering work in time, thereby ensuring the filtering effect.

[0072] The number of the cleaning nozzles 59 can be set according to actual needs. In some embodiments, at least two cleaning nozzles 59 are provided to respectively spray cleaning liquid toward a portion of the filter 52 located between the second gear 55 and the third gear 56, and to spray cleaning liquid toward a portion of the filter 52 located between the first gear 54 and the third gear 56, thereby effectively cleaning the filter 52 and ensuring the filtering effect.

[0073] The embodiment of the present invention further provides a grinding liquid recovery method, which uses the above-mentioned grinding liquid recovery device to recycle and reuse the grinding liquid. The grinding liquid recovery method comprises:

[0074] The iron chips in the waste grinding liquid are removed by the iron removal structure;

[0075] The small waste particles in the grinding liquid waste are removed by a centrifugal structure;

[0076] The impurities in the grinding liquid waste are further removed through the filtering structure.

[0077] The grinding liquid is recovered and processed by the iron removal structure, the centrifugal structure and the filtering structure, so as to be recycled and reused, thereby improving the utilization rate of the grinding liquid and saving the amount of grinding liquid used.

[0078] In an exemplary embodiment, the step of removing iron filings from the waste grinding liquid by the iron removal structure specifically includes:

[0079] Insert the magnetic rod 2 into the second accommodating cavity 12 so that the iron filings in the waste liquid entering the first accommodating cavity 11 are adsorbed onto the outer wall of the second accommodating cavity 12;

[0080] The magnetic rod 2 is taken out from the second accommodating cavity 12, and the iron filings adsorbed on the outer wall of the second accommodating cavity 12 lose their adsorption force and fall into the first accommodating cavity 11. Cleaning liquid is introduced into the first accommodating cavity 11 to clean the outer walls of the first accommodating cavity 11 and the second accommodating cavity 12.

[0081] In an exemplary embodiment, impurities in the waste grinding liquid are further removed by a filtering structure, including:

[0082] Controlling the three gears to rotate, so as to drive the filter screen 52 to rotate;

[0083] Start the cleaning nozzle 59 so that the cleaning nozzle 59 sprays cleaning liquid toward the area corresponding to the filter screen 52;

[0084] The grinding liquid after centrifugation is introduced and the grinding liquid is filtered.

[0085] There are a few points to note:

[0086] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0087] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0088] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0089] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A grinding liquid recovery device, characterized in that: Including iron removal structure, centrifugal structure and filtration structure: The iron removal structure includes a shell and a magnetic part. A first accommodating cavity for accommodating waste liquid is arranged in the shell. At least one second accommodating cavity for accommodating the magnetic part is also arranged in the shell. The second accommodating cavity is arranged independently of the first accommodating cavity, and at least one end of the second accommodating cavity passes through the corresponding side wall of the first accommodating cavity.

2. The grinding liquid recovery device according to claim 1, characterized in that: The magnetic part includes a magnetic rod and a moving structure, and the moving structure is used to control the second accommodating cavity to be inserted into or separated from the second accommodating cavity.

3. The grinding liquid recovery device according to claim 1, characterized in that: The first accommodating cavity and the second accommodating cavity are an integral structure or a separate structure.

4. The grinding liquid recovery device according to claim 1, characterized in that: The second accommodating cavity is a hollow columnar structure, and the axial direction of the second accommodating cavity is parallel to the first direction, and the first direction is the direction from the bottom of the shell to the top of the shell.

5. The grinding liquid recovery device according to claim 4, characterized in that: A first waste liquid inlet is arranged at the top of the shell, a first waste liquid outlet is arranged at the bottom of the shell, and the second accommodating cavity is located between the first waste liquid inlet and the first waste liquid outlet.

6. The grinding liquid recovery device according to claim 5, characterized in that: The housing comprises a rectangular body, and the first waste liquid inlet and the second waste liquid outlet are located at diagonal positions of the housing.

7. The grinding liquid recovery device according to claim 1, characterized in that: A cleaning liquid inlet is arranged at the top of the shell, and a cleaning liquid outlet is arranged at the bottom of the shell. The shell comprises a rectangular body, and the cleaning liquid inlet and the cleaning liquid outlet are located at diagonal positions of the shell.

8. The grinding liquid recovery device according to claim 1, characterized in that: A centrifugal structure is also included for separating small waste particles from the waste liquid.

9. The grinding liquid recovery device according to claim 8, characterized in that: The centrifugal structure is a cyclone centrifugal structure, comprising a funnel-shaped outer shell and a rotating shaft located in the outer shell, and blades are arranged on the outer peripheral surface of the rotating shaft.

10. The grinding liquid recovery device according to claim 1, characterized in that: It also includes a filtering structure, the filtering structure includes a third accommodating cavity, a third waste liquid inlet is arranged at the top of the third accommodating cavity, and a fourth waste liquid outlet is arranged at the bottom of the third accommodating cavity; The filtering structure includes a filter screen and a collecting tray located inside the third accommodating cavity. The collecting tray is used to collect the grinding liquid filtered by the filter screen. A through hole is provided at the bottom of the collecting tray. The through hole is connected to a pipe, and the pipe is arranged through the side wall of the third accommodating cavity.

11. The grinding liquid recovery device according to claim 10, characterized in that: The filtering structure further includes three gears distributed in a triangle shape, the three gears including a first gear and a second gear disposed near the second waste liquid inlet, and a line connecting the centers of the first gear and the second gear is perpendicular to the flow direction of the waste liquid entering from the second waste liquid inlet; The filter screen is arranged around the three rotating wheels and rotates in a first plane driven by the three rotating wheels, wherein the first plane is parallel to the flow direction of the waste liquid entering from the second waste liquid inlet; The collecting tray is located inside the filter screen and directly below a line connecting the centers of the first gear and the second gear.

12. The grinding liquid recovery device according to claim 10, characterized in that: The three gears also include a third gear, and the filtering structure also includes a cleaning part for cleaning the filter net, and the cleaning part includes a cleaning nozzle located inside the triangle formed by the three gears, and the cleaning nozzle sprays cleaning liquid toward the part of the filter net located between the second gear and the third gear, or the cleaning nozzle sprays cleaning liquid toward the part of the filter net located between the first gear and the third gear.

13. A method for recovering a grinding liquid, characterized in that: The grinding liquid recovery device according to any one of claims 1 to 12 is used to recycle the grinding liquid, and the grinding liquid recovery method comprises: The iron chips in the waste grinding liquid are removed by the iron removal structure; The small waste particles in the grinding liquid waste are removed by a centrifugal structure; Impurities including silicon slag in the grinding liquid waste are further removed by the filtering structure.

14. The grinding liquid recovery method according to claim 13, characterized in that: The steps of removing iron chips from the waste grinding liquid by the iron removal structure specifically include: Inserting the magnetic rod into the second accommodating cavity, so that the iron filings in the waste liquid entering the first accommodating cavity are adsorbed onto the outer wall of the second accommodating cavity; The magnetic rod is taken out from the second accommodating cavity, and a cleaning liquid is introduced into the first accommodating cavity to clean the outer walls of the first accommodating cavity and the second accommodating cavity.

Images