Method for recovering and reusing cutting lines
Through the recycling and secondary utilization of cutting lines, the problem of high cutting cost of silicon materials in the photovoltaic industry is solved. Through the treatment and sand plating, the utilization rate and cost-effectiveness of cutting lines are improved, multiple uses are achieved and production is reduced. cost.
Patent Information
- Application Number
- CN202310693750.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-12
- Publication Date
- 2024-12-13
AI Technical Summary
In the photovoltaic industry, silicon material loss is large when cutting silicon material, resulting in higher costs. Although the existing methods of reducing the cutting line diameter or using high-strength materials can reduce the loss of silicon material, the use cost of cutting lines is relatively high. Overall production No significant reduction in cost.
The method of recycling and secondary utilization of cutting lines includes processing, sand plating, and cleaning and drying under specific conditions to improve the utilization and cost-effectiveness of cutting lines.
Through the selection of specific tool counts and processing conditions, multiple use of cutting lines is achieved, reducing the cost of cutting lines, avoiding waste treatment after disconnection, improving the utilization rate of cutting lines, and suitable for various materials and type of cutting line.
Smart Images
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Figure BDA0004283215090000111
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of wire cutting in single crystal silicon manufacturing, and in particular to a method for recycling and reusing a cutting wire. Background Art
[0002] In the photovoltaic industry, the main silicon material cutting tool is the electroplated diamond wire saw. Due to the large loss of silicon material when cutting silicon material, the cost is high, and the cost per kilowatt-hour cannot be reduced, which is not conducive to the development of the photovoltaic industry. To solve the above problems, the usual method is to reduce the cutting wire diameter or develop and introduce high-strength performance materials (such as tungsten wire). Although the above methods can reduce the loss of silicon material, the cost of using the cutting wire is high, and the overall production cost is not significantly reduced. Summary of the invention
[0003] The purpose of the present disclosure is to provide a method for recycling and reusing a cutting wire, which can improve the utilization rate of the cutting wire and reduce the use cost of the cutting wire.
[0004] In order to achieve the above object, the present disclosure provides a method for recycling and reusing a cutting wire, the method comprising the following steps:
[0005] S1, processing the used cutting line to obtain a processed cutting line;
[0006] S2, performing sand plating on the treated cutting wire;
[0007] S3, reusing the cutting wire after the sand plating treatment;
[0008] The process comprises the following steps:
[0009] a. contacting the used cutting wire with a first cleaning liquid to obtain a first product;
[0010] b. contacting the first product with a reaction solution for a second time to obtain a second product, wherein the reaction solution comprises a mixed solution of sodium chloride and nitric acid;
[0011] c. contacting the second product with a second cleaning liquid for a third time to obtain the treated cutting line;
[0012] The used cutting wire is a ring-shaped wire with less than 100 cuts, or a metal wire with less than 100 cuts.
[0013] Optionally, the used cutting wire is a ring wire with 80-100 cuts, or a metal wire with 80-100 cuts.
[0014] Optionally, the conditions of the first contact include: time of 1-3h, temperature of 15-50°C;
[0015] The conditions of the second contact include: time of 2-5 min, temperature of 20-100° C.;
[0016] The conditions of the third contact include: time of 5-30 min and temperature of 15-50°C.
[0017] Optionally, the first cleaning solution and the second cleaning solution are the same or different, and each comprises 500-5000 mL of a sodium chloride solution with a concentration of 20-60 wt %.
[0018] Optionally, the first cleaning liquid and the second cleaning liquid are the same.
[0019] Optionally, in step b, the method for preparing the reaction solution comprises: mixing a sodium chloride solution and a nitric acid solution;
[0020] The concentration of the sodium chloride solution is 20-60% by weight, and the volume is 3000-5000 mL; the concentration of the nitric acid solution is 50-75% by weight, and the volume is 30-150 mL.
[0021] Optionally, step a further comprises: drying the product obtained by the first contact at 50-80° C. for 10-120 min to obtain the first product;
[0022] Step c also includes: drying the product obtained by the third contact at 50-80° C. for 10-120 min to obtain the treated cutting line.
[0023] Optionally, in step a, the number of cutting lines that are simultaneously subjected to the first contact in the same container is 10 or less;
[0024] In step c, the number of cutting lines that are simultaneously subjected to the third contact in the same container is 10 or less.
[0025] Optionally, in step S3, the feed displacement of the sand-plated cutting wire remains unchanged;
[0026] The conditions for the secondary utilization include: a feed speed of 20-50 mm / min, a tension of 60-90 N, a wire bow time of 0.5-2 min, a feed time of 6-8 min for round bars, and a feed time of 5-7 min for square bars.
[0027] Optionally, the method further comprises: before step S1, collecting the used cutting wire;
[0028] The collecting of the used cutting wires comprises: alternately crossing and folding the used cutting wires into double helices, and storing them at 15-40° C.;
[0029] The total number of double helical crossings is 2-4 times;
[0030] The total number of foldings is 2-4 times;
[0031] Optionally, the total number of double helical crossings is the same as the total number of double folds.
[0032] Through the above technical scheme, the present invention selects a cutting wire with a specific number of blades and combines it with specific processing conditions to recycle and reuse the used cutting wire, thereby improving the utilization rate of the cutting wire and reducing the cost; avoiding the disadvantage that the cutting wire can only be discarded after it breaks.
[0033] Other features and advantages of the present disclosure will be described in detail in the following detailed description. DETAILED DESCRIPTION
[0034] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.
[0035] The present disclosure provides a method for recycling and reusing a cutting wire, the method comprising the following steps:
[0036] S1, processing the used cutting line to obtain a processed cutting line;
[0037] S2, performing sand plating on the treated cutting wire;
[0038] S3, reusing the cutting wire after the sand plating treatment;
[0039] The process comprises the following steps:
[0040] a. contacting the used cutting wire with a first cleaning liquid to obtain a first product;
[0041] b. contacting the first product with a reaction solution for a second time to obtain a second product, wherein the reaction solution comprises a mixed solution of sodium chloride and nitric acid;
[0042] c. contacting the second product with a second cleaning liquid for a third time to obtain the treated cutting line;
[0043] The used cutting wire is a ring-shaped wire with less than 100 cuts, or a metal wire with less than 100 cuts.
[0044] The present invention selects a cutting wire with a specific number of blades and combines it with specific processing conditions to recycle and reuse the used cutting wire. The cutting wire can be used multiple times, avoiding the disadvantage that the cutting wire can only be discarded after it breaks, thereby improving the utilization rate of the cutting wire, reducing costs, and being suitable for cutting wires of various materials and types.
[0045] In the present disclosure, cutting wire refers to a metal wire whose surface is sand-plated to have wire sawing capability; loop wire refers to a loop wire formed by weaving multiple strands of fine wires, which is sand-plated as a whole after weaving, or a specially made single-strand diamond sand wire is connected end to end to form a loop; metal wire refers to a non-loop cutting wire.
[0046] In the present disclosure, the busbar refers to the middle of the ring-shaped wire, which plays the role of supporting the outer sub-wires and is connected end to end, and can withstand a large tensile force. The material can be carbon steel, metal tungsten and other metal materials. This is conventional in the field and the present disclosure does not make specific requirements.
[0047] In the present disclosure, the sub-line refers to the outer circle of the ring-shaped line, which is woven back and forth around the main line and crimped to the upper circle line at both ends. It is characterized by a thin wire diameter, generally a thin steel wire.
[0048] In the present disclosure, the grain size of corundum refers to fine granular irregular diamonds, also called corundum, with a size between 25-400 μm, which are generally sorted using a specific sieve.
[0049] In the present disclosure, annular wire cutting is divided into normal annular wire cutting, abnormal annular wire cutting, graphite annular wire cutting, etc. This is conventional in the art and will not be elaborated here.
[0050] The present disclosure does not make specific requirements on parameters such as the type, size, and material of the cutting line, that is, the above parameters do not affect the technical effects of the present application.
[0051] In this disclosure, room temperature refers to 25°C.
[0052] According to one embodiment of the present disclosure, the used cutting wire is a ring-shaped wire with 80-100 cutters, or a metal wire with 80-100 cutters; the number of cutters used for the ring-shaped wire can be, for example, 80, 85, 87, 90, 95, 100, etc., and the number of cutters used for the metal wire can be, for example, 80, 85, 87, 90, 95, 100, etc.; the wire body of the cutting wire with the above number of cutters can continue to be used, saving material costs and weaving costs compared to new wires.
[0053] According to one embodiment of the present disclosure, the conditions for the first contact include: time of 1-3h, for example, 1h, 2h, 3h, etc.; temperature of 15-50°C, for example, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, etc.
[0054] According to one embodiment of the present disclosure, the conditions for the second contact include: a time of 2-5 min, for example, 2 min, 3 min, 4 min, 5 min, etc.; a temperature of 20-100°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc.
[0055] According to one embodiment of the present disclosure, the conditions for the third contact include: a time of 5-30 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc.; a temperature of 15-50°C, for example, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, etc.
[0056] According to one embodiment of the present disclosure, the first cleaning liquid and the second cleaning liquid are the same or different, and respectively include 500-5000mL of a sodium chloride solution with a concentration of 20-60 weight %, and the concentration of the sodium chloride solution can be, for example, 20 weight %, 30 weight %, 40 weight %, 50 weight %, 60 weight %, etc.; optionally, the first cleaning liquid and the second cleaning liquid are the same, and the use of the above cleaning liquid can complete the cleaning of dirt on the surface of the old line, which has a positive effect on the electrochemical reaction of the subsequent process.
[0057] According to one embodiment of the present disclosure, in step b, the method for preparing the reaction solution includes: mixing a sodium chloride solution with a nitric acid solution, specifically, adding a nitric acid solution dropwise into the sodium chloride solution and mixing them evenly; the concentration of the sodium chloride is 20-60% by weight, and the concentration of the sodium chloride solution can be, for example, 20% by weight, 30% by weight, 40% by weight, 50% by weight, 60% by weight, etc., and the volume is 3000-5000mL; the concentration of the nitric acid is 50-75% by weight, and the concentration of the nitric acid can be, for example, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, etc.; the volume is 30-150mL, and the above reaction solution is simple to prepare. The use of the above reaction solution can fully and efficiently remove the old coating without damaging the wire body, and as long as the wire body is intact, the cutting wire can be treated multiple times by the method of the present application and reused in a cycle.
[0058] According to one embodiment of the present disclosure, step a also includes: drying the product obtained by the first contact at 50-80°C for 10-120 min to obtain the first product, wherein the temperature can be, for example, 50°C, 60°C, 70°C, 80°C, etc., and the time can be, for example, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc.
[0059] According to one embodiment of the present disclosure, step c also includes: drying the product obtained by the third contact at 50-80°C for 10-120 min to obtain the treated cutting line, wherein the temperature can be, for example, 50°C, 60°C, 70°C, 80°C, etc., and the time can be, for example, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc.
[0060] According to one embodiment of the present disclosure, the number of cleaning cutting lines can be appropriately increased according to the size of the container. To ensure the cleaning effect, in step a, the number of cutting lines that simultaneously perform the first contact in the same container is less than 10; in step c, the number of cutting lines that simultaneously perform the third contact in the same container is less than 10.
[0061] Because the wire has been used, the length will increase by 5-10mm according to the ductility of the metal. In order to reuse the treated cutting wire, according to an embodiment of the present disclosure, in step S3, the feed displacement of the sand-plated cutting wire remains unchanged, and the conditions for the secondary utilization include: the feed speed is 20-50mm / min, for example, it can be 20mm / min, 30mm / min, 40mm / min, 50mm / min, etc.; the tension is 60-90N, for example, it can be 60N, 70N, 80N, 90N, etc.; the wire bow time is 0.5-2min, for example, it can be 0.5min, 1.0min, 1.5min, 2.0min, etc.; the feed time of the round rod is 6-8min, for example, it can be 6min, 6.5min, 7min, 7.5min, 8min, etc.; the feed time of the square rod is 5-7min, for example, it can be 5min, 5.5min, 6min, 6.5min, 7min, etc.
[0062] According to one embodiment of the present disclosure, in order to cause less damage to the wire body and facilitate collection, the method also includes: before step S1, collecting the used cutting wire; the collecting of the used cutting wire includes: alternately double-helix crossing and folding the used cutting wire, and storing it at 15-40°C; the total number of double-helix crossings is 2-4 times; the total number of foldings is 2-4 times; the total number of double-helix crossings and the total number of foldings are preferably the same; wherein, "double-helix crossing" refers to spreading the two ends of the cutting wire with both hands, rotating it once, and then crossing the two wires; "folding in half" refers to folding the cutting wire in half after the double-helix crossing.
[0063] In the present disclosure, sand plating refers to burying metal wires or braided sub-wires and busbar structures in a mixture of corundum and nickel solution, attaching them to the wire body through an external power supply, winding copper rings on the wire body, connecting wires as cathodes, nickel sulfamate solution as electrolytes, and nickel beads as anodes. After the power is turned on, nickel ions adhere to the surface of the steel wire, and the anodes (nickel beads) continuously provide nickel molecules. The grain size of corundum needs to be greater than 1 / 2 of the thickness of the nickel plating layer to ensure that the corundum is fixed and exposed; the specific conditions for sand plating are conventional in the art and are not required here. For example, the same method and conditions as the sand plating of a new wire can be used. The present disclosure does not specifically limit the size and other parameters of the sand-plated cutting wire. After the sand plating is completed, the sand-plated wire is washed with water and then dried.
[0064] The present disclosure will be further illustrated by examples below, but the present disclosure is not limited thereby. The instruments and reagents used in the examples of the present disclosure are all commonly used instruments and reagents by those skilled in the art unless otherwise specified.
[0065] The breaking force testing method in the examples is conventional in the art.
[0066] Examples 1-5
[0067] The following steps were used to recycle and reuse the cutting wires of samples numbered 1-5. The test parameters of the processed cutting wires are listed in Table 1:
[0068] (1) Use a 80-knife round bar ring wire (ring-shaped diamond wire saw, specification 0.5mm, length 2960mm), return all moving parts to their original state, open the protective door, press the tension wheel with your left hand, remove the wire from the wire groove contact point with your right hand, then remove the wire from the two driven wheels in turn, and finally remove the driving wheel wire.
[0069] (2) Spread the two ends of the loop wire with both hands, rotate it with the right hand once, cross the two strands, and then fold it in half. According to the above winding steps, repeat it twice in sequence, for a total of 4 turns, put it into a special collection bag for loop wire, seal it, and place it in a collection box for old wires, and store it at 26°C away from light. After collecting a certain amount of old wires, open the collection box, take out the old wire collection bag, disassemble the loop wire folded in half 4 times, and put it into the first cleaning solution (5000mL of 50 wt% NaCl solution) at room temperature for the first contact time of 3 hours. The number of loop wires immersed can be appropriately increased according to the size of the container, and the maximum number should not exceed 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 50°C, after 10 minutes, put it into the reaction solution (add 100mL of 75% by weight concentrated nitric acid solution to 4900mL of 50% by weight NaCl solution and mix well) and carry out the second contact at room temperature for 4.5 minutes. Use a glass rod to pick up the wire from one end and put it into the second cleaning solution (5000mL of 50% by weight NaCl solution) and carry out the third contact at room temperature for 20 minutes. The number of cleaned ring wires can be appropriately increased according to the size of the container, and the maximum number is no more than 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 80°C, after 10 minutes, obtain the treated cutting wire;
[0070] (3) After the wires are collected separately, the surface of the wires is checked for obvious breakage, wear and tear, and creases, and then sand plating is performed. The conditions and steps of the sand plating are the same as those of a new wire, which are conventional in the art;
[0071] (4) Secondary use under the following conditions:
[0072] ①Feed speed: 32mm / min;
[0073] ②The feed displacement remains unchanged;
[0074] ③Tension: 70±10N;
[0075] ④ Feeding time: round bar 7.65min;
[0076] ⑤Line bow time: 1.5min.
[0077] Example 6
[0078] The following steps were used to recycle and reuse the cutting wire of sample No. 6. The test parameters of the processed cutting wire are listed in Table 1:
[0079] (1) Use a 90-knife round bar ring wire (ring-shaped diamond wire saw, specification 0.5mm, length 2960mm), return all moving parts to their original state, open the protective door, press the tension wheel with your left hand, remove the wire from the wire groove contact point with your right hand, then remove the wire from the two driven wheels in turn, and finally remove the driving wheel wire.
[0080] (2) Spread the two ends of the loop wire with both hands, rotate it with the right hand once, cross the two strands, and then fold it in half. According to the above winding steps, repeat it twice in sequence, for a total of 4 turns, put it into a special collection bag for loop wire, seal it, and place it in a collection box for old wires, and store it at 26°C away from light. After collecting a certain amount of old wires, open the collection box, take out the old wire collection bag, disassemble the loop wire folded in half 4 times, put it into the first cleaning solution (5000mL of 20 wt% NaCl solution) at 50°C for the first contact for 1 hour. The number of loop wires immersed can be appropriately increased according to the size of the container, and the maximum number should not exceed 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 65°C, after 60 minutes, put it into the reaction solution (add 30 mL of 50% by weight concentrated nitric acid solution to 3000 mL of 20% by weight NaCl solution and mix well) for the second contact at 50°C for 2 minutes, use a glass rod to pick up the wire from one end, put it into the second cleaning solution (5000 mL of 20% by weight NaCl solution) for the third contact at 15°C for 30 minutes, and the number of cleaned ring wires can be appropriately increased according to the size of the container, and the maximum number is no more than 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 50°C, after 120 minutes, obtain the treated cutting wire;
[0081] (3) After the wires are collected separately, the surface of the wires is checked for obvious breakage, wear and tear, and creases, and then sand plating is performed. The conditions and steps of the sand plating are the same as those of a new wire, which are conventional in the art;
[0082] (4) Secondary use under the following conditions:
[0083] ①Feed speed: 20mm / min;
[0084] ②The feed displacement remains unchanged;
[0085] ③Tension: 80±10N;
[0086] ④ Feeding time: 6min for round bar;
[0087] ⑤Line bow time: 0.5min.
[0088] Example 7
[0089] The following steps were used to recycle and reuse the cutting wire of sample No. 7. The test parameters of the processed cutting wire are listed in Table 1:
[0090] (1) Use a 100-knife round bar ring wire (ring-shaped diamond wire saw, specification 0.5mm, length 2960mm), return all moving parts to their original state, open the protective door, press the tension wheel with your left hand, remove the wire from the wire groove contact point with your right hand, then remove the wire from the two driven wheels in turn, and finally remove the driving wheel wire.
[0091] (2) Spread the two ends of the loop wire with both hands, rotate it with the right hand once, cross the two strands, and then fold it in half. According to the above winding steps, repeat it twice in sequence, for a total of 4 turns, put it into a special collection bag for loop wire, seal it, and place it in a collection box for old wires, and store it at 26°C away from light. After collecting a certain amount of old wires, open the collection box, take out the old wire collection bag, disassemble the loop wire folded in half 4 times, put it into the first cleaning solution (5000mL of 40 wt% NaCl solution) at 15°C for the first contact for 2 hours. The number of loop wires immersed can be appropriately increased according to the size of the container, and the maximum number should not exceed 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 80°C, after 120 minutes, put it into the reaction solution (add 90 mL of 60 wt% concentrated nitric acid solution to 4000 mL of 40 wt% NaCl solution and mix well) for the second contact at 100°C for 3.5 minutes, use a glass rod to pick up the wire from one end, put it into the second cleaning solution (5000 mL of 40 wt% NaCl solution) for the third contact at 50°C for 5 minutes, and the number of cleaned ring wires can be appropriately increased according to the size of the container, and the maximum number is no more than 10. Take the cleaned ring wire, take it out and hang it up individually, at a temperature of 65°C, after 60 minutes, obtain the treated cutting wire;
[0092] (3) After the wires are collected separately, the surface of the wires is checked for obvious breakage, wear and tear, and creases, and then sand plating is performed. The conditions and steps of the sand plating are the same as those of a new wire, which are conventional in the art;
[0093] (4) Secondary use under the following conditions:
[0094] ①Feed speed: 50mm / min;
[0095] ②The feed displacement remains unchanged;
[0096] ③Tension: 80±10N;
[0097] ④ Feeding time: round bar 8min;
[0098] ⑤Line bow time: 2min.
[0099] Table 1
[0100]
[0101]
[0102] According to the data in Table 1 above, the life of the cutting wire treated by the method of the present application is 90-130 cuts when it is reused, and the average life is 111.4 cuts; it is known in the art that the normal life of a new wire is 100-120 cuts. According to the data comparison, the life of the cutting wire treated by the method of the present application is close to that of a new wire when it is reused. Therefore, the cutting wire recycled and treated by the method disclosed in the present invention can be reused, which improves the utilization rate of the cutting wire and reduces the cost.
[0103] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0105] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A method for recycling and reusing a cutting wire, characterized in that: The method comprises the following steps: S1, processing the used cutting line to obtain a processed cutting line; S2, performing sand plating on the treated cutting wire; S3, reusing the cutting wire after the sand plating treatment; The process comprises the following steps: a. contacting the used cutting wire with a first cleaning liquid to obtain a first product; b. contacting the first product with a reaction solution for a second time to obtain a second product, wherein the reaction solution comprises a mixed solution of sodium chloride and nitric acid; c. contacting the second product with a second cleaning liquid for a third time to obtain the treated cutting line; The used cutting wire is a ring-shaped wire with less than 100 cuts, or a metal wire with less than 100 cuts.
2. The method according to claim 1, wherein: The used cutting wire is a ring wire with 80-100 cuts, or a metal wire with 80-100 cuts.
3. The method according to claim 1, wherein: The conditions of the first contact include: time of 1-3h, temperature of 15-50°C; The conditions of the second contact include: time of 2-5 min, temperature of 20-100° C.; The conditions of the third contact include: time of 5-30 min and temperature of 15-50°C.
4. The method according to claim 1, wherein: The first cleaning solution and the second cleaning solution are the same or different, and each includes 500-5000 mL of a sodium chloride solution with a concentration of 20-60% by weight.
5. The method according to claim 4, wherein: The first cleaning liquid and the second cleaning liquid are the same.
6. The method according to claim 1, wherein: In step b, the method for preparing the reaction solution comprises: mixing a sodium chloride solution and a nitric acid solution; The concentration of the sodium chloride solution is 20-60% by weight, and the volume is 3000-5000 mL; the concentration of the nitric acid solution is 50-75% by weight, and the volume is 30-150 mL.
7. The method according to claim 1, wherein: Step a further comprises: drying the product obtained by the first contact at 50-80° C. for 10-120 min to obtain the first product; Step c also includes: drying the product obtained by the third contact at 50-80° C. for 10-120 min to obtain the treated cutting wire.
8. The method according to claim 1, wherein: In step a, the number of cutting lines that are simultaneously subjected to the first contact in the same container is less than 10; In step c, the number of cutting lines that are simultaneously subjected to the third contact in the same container is 10 or less.
9. The method according to claim 1, wherein: In step S3, the feeding displacement of the sand-plated cutting wire remains unchanged; The conditions for the secondary utilization include: a feed speed of 20-50 mm / min, a tension of 60-90 N, a wire bow time of 0.5-2 min, a feed time of 6-8 min for round bars, and a feed time of 5-7 min for square bars.
10. The method according to claim 1, wherein: The method further comprises: before step S1, collecting the used cutting wire; The collecting of the used cutting wires comprises: alternately crossing and folding the used cutting wires into double helices, and storing them at 15-40° C.; The total number of double helical crossings is 2-4 times; The total number of foldings is 2-4 times; Optionally, the total number of double helical crossings is the same as the total number of double folds.