Detection method for recycled tin and method for preparing lead-free tin bar, tin wire, tin sheet and tin bar

Abstract

The invention relates to the technical field of tin recovery, in particular to a detection method for recovered tin and a method for preparing a lead-free tin bar, a tin wire, a tin sheet and a tin bar, and the detection method for recovered tin comprises the steps that S1, the surface of a tin block is cleaned; s2, the tin block is placed in a fluxing agent; s3, the fluxing agent is heated to 240 DEG C to 290 DEG C, so that the tin block is melted into tin beads; and S4, the tin beads are cooled to the room temperature in the fluxing agent. If black substances exist on the surfaces of the cooled tin balls, it is determined that the recycled tin blocks cannot be used for production. And if no black substance exists on the surface of the cooled tin bead, the recovered tin block can be directly used for production. Therefore, the quality of the recycled tin can be quickly distinguished.

Description

Technical Field

[0001] This application relates to the field of tin recycling technology, and in particular to a method for detecting recycled tin and a method for preparing lead-free tin rods, tin wires, tin sheets, and tin bars. Background Technology

[0002] In recent years, the booming development of the semiconductor and photovoltaic industries has driven up tin consumption, making tin resources increasingly scarce. Recycling tin from tin-containing waste can reduce environmental pollution and allow tin to be reused.

[0003] However, the purity of recycled tin is greatly affected by the type of waste and the recycling process. Therefore, how to quickly identify the quality of recycled tin has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In order to quickly identify the quality of recycled tin, this application provides a method for detecting recycled tin and a method for preparing lead-free tin rods, tin wires, tin sheets, and tin bars.

[0005] The primary objective of this application is to provide a method for detecting recycled tin, employing the following technical solution: A method for detecting recycled tin, comprising: Step S1: Clean the surface of the solder block; Step S2: Place the tin block into the flux; Step S3: Heat the flux to 240℃-290℃ to melt the tin block into tin beads; Step S4: Cool the solder balls to room temperature in the flux.

[0006] By employing the above technical solution, cleaning the surface of the tin ingot effectively removes impurities adhering to the surface of the recycled tin, reducing the impact of surface impurities on the test results and improving the accuracy and reliability of the test results. The flux provides a stable high-temperature environment for the melting of the tin ingot and enables the tin ingot to be heated uniformly, melting and forming tin beads. At high temperatures, the flux can form a thin film on the tin surface, isolating oxygen in the air from the molten tin, preventing oxidation, and ensuring that the black material on the surface of the tin beads is inherent to the tin material itself, rather than being produced by reaction with the outside air. Simultaneously, the hygroscopic nature of the flux allows it to absorb moisture from the environment and keep the system moist, indirectly reducing the oxidation rate of tin at high temperatures. Furthermore, the flux assists in the formation of tin beads, reducing molten tin loss. The flux is heated to 240℃-290℃ to melt the tin ingot into tin beads. The tin beads are then cooled to room temperature in the flux. If black substances are present on the surface of the cooled tin beads, the recycled tin ingot is considered unusable for production. If no black substance appears on the surface of the cooled tin beads, the recycled tin can be used directly in production. This allows for quick identification of the quality of the recycled tin.

[0007] This application further specifies that the flux is glycerol, diglycerol, sorbitol, polyethylene glycol 200, or polyethylene glycol 400.

[0008] This application further specifies that the flux comprises the following raw materials by weight percentage: sodium silicate 5-15%, glycerin 100%.

[0009] By employing the above technical solution, sodium silicate, when heated in a glycerol system, decomposes to form a glassy molten layer rich in silica, uniformly covering the surface of the tin beads. This physically isolates the air from contact with the tin, inhibiting the formation of tin oxide. Silicate ions in the silicate can undergo a complexation reaction with tin ions, forming a dense tin-silicate composite film on the tin surface. This film is chemically bonded to the tin surface, improving corrosion resistance, and its structural stability is superior to that of a simple oxide film. The high viscosity of glycerol slows down the flow and loss of the silicate molten layer, prolonging the duration of the protective film. Simultaneously, the hydroxyl groups in the glycerol molecules form hydrogen bonds with the metal cations in the silicate, enhancing the adhesion between the film and the tin surface. This can further improve the accuracy of detection.

[0010] This application further specifies that in step S2, the flux level is at least 2 cm above the top of the tin block.

[0011] The second objective of this application is to provide a method for preparing lead-free solder rods, employing the following technical solution: A method for preparing lead-free solder rods using solder beads includes: Step S1: Mix 2-4% Ag by weight, 0.3-0.7% Cu, and the balance tin beads and heat to form a first molten mixture, and make the first molten mixture homogeneous; Step S2: Cast lead-free solder rods using the first molten mixture.

[0012] The third objective of this application is to provide a method for preparing lead-free tin wire, which adopts the following technical solution: A method for preparing lead-free solder wire using solder beads, comprising: Step S1: Mix 0.3-0.7% Ag and 0.5-0.9% Cu by weight, with the balance being tin beads, and heat to form a second molten mixture, and make the second molten mixture homogeneous; Step S2: Cast the second molten mixture into a solder bar; Step S3: The solder rod is extruded and drawn to form lead-free solder wire.

[0013] This application is further configured such that: in step S3, during extrusion, flux with a weight ratio of 0-4% is added.

[0014] The fourth objective of this application is to provide a method for preparing lead-free tin sheets, which adopts the following technical solution: A method for preparing lead-free tin sheets using tin beads includes: Step S1: Mix 2-4% Ag, 0.3-0.7% Cu by weight, with the balance being tin beads, heat to form a third molten mixture, and ensure the third molten mixture is homogenized; Step S2: Cast the third molten mixture into a solder bar; Step S3: The solder rod is extruded to form a solder sheet; Step S4: Apply 0-5% by weight of flux to the surface of the solder sheet and dry it to obtain lead-free solder sheet.

[0015] The fifth objective of this application is to provide a method for preparing lead-free solder bars, which adopts the following technical solution: A method for preparing lead-free solder bars using solder beads includes: Step S1: Mix and heat 0-0.7% Ag, 0.3-0.9% Cu, 0-0.1% Ni by weight, with the balance being tin beads, to form a fourth molten mixture, and make the fourth molten mixture homogeneous; Step S2: Cast lead-free solder bars using the fourth molten mixture.

[0016] In summary, the beneficial technical effects of this application are as follows: 1. Cleaning the surface of the tin ingot effectively removes impurities adhering to the surface of the recycled tin, reducing the impact of surface impurities on test results and improving the accuracy and reliability of the results. The flux provides a stable high-temperature environment for the melting of the tin ingot and ensures uniform heating, allowing the tin ingot to melt and form tin beads. At high temperatures, the flux forms a thin film on the tin surface, isolating oxygen from the molten tin and preventing oxidation. This ensures that the black material on the surface of the tin beads is inherent to the tin itself, rather than resulting from a reaction with the outside air. Simultaneously, the flux's hygroscopic nature allows it to absorb moisture from the environment and keep the system moist, indirectly reducing the oxidation rate of tin at high temperatures. Furthermore, the flux assists in the formation of tin beads, reducing molten tin loss. The flux is heated to 240℃-290℃ to melt the tin ingot into tin beads. The tin beads are then cooled to room temperature in the flux. If black substances are present on the surface of the cooled tin beads, the recycled tin ingot is considered unusable for production. If no black substance appears on the surface of the cooled tin beads, the recycled tin can be used directly in production. This allows for quick identification of the quality of the recycled tin.

[0017] 2. When sodium silicate is heated in a glycerol system, it decomposes to form a glassy molten layer rich in silica, uniformly covering the surface of the tin beads. This physically isolates the tin from air contact and inhibits the formation of tin oxide. The silicate ions in the silicate can undergo a complexation reaction with tin ions, forming a dense tin-silicate composite film on the tin surface. This film is chemically bonded to the tin surface, improving corrosion resistance, and its structural stability is superior to that of a simple oxide film. The high viscosity of glycerol slows down the flow and loss of the silicate molten layer, prolonging the duration of the protective film. Simultaneously, the hydroxyl groups in the glycerol molecules form hydrogen bonds with the metal cations in the silicate, enhancing the adhesion between the film and the tin surface. This can further improve the accuracy of detection. Attached Figure Description

[0018] Figure 1 This is a flowchart of an embodiment of a method for detecting recycled tin; Figure 2 This is an image of the first sample after being detected using the detection method shown in Example 1; Figure 3 This is an image of the second sample after being detected using the detection method shown in Example 1. Detailed Implementation

[0019] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0020] Reference Figure 1 This application discloses a method for detecting recycled tin, comprising: Step S1: Clean the surface of the tin block.

[0021] This application does not impose any particular limitation on the cleaning agent used to clean the surface of the solder block. Any known cleaning agent can be used in this application without departing from the inventive concept. Examples such as using alcohol or ethyl acetate as cleaning agents are merely illustrative and not intended to limit the scope of protection.

[0022] This application does not specifically limit the cleaning method. Any known cleaning agent can be used in this application without departing from the inventive concept. The examples provided are merely illustrative and not intended to limit the scope of protection. The surface of the tin block is cleaned by wiping and drying or rinsing and drying.

[0023] It is understandable that cleaning the surface of the tin block can effectively remove impurities adhering to the surface of the recycled tin, reduce the impact of surface impurities on the test results, and improve the accuracy and reliability of the test results.

[0024] Step S2: Place the tin block in the flux.

[0025] This application does not impose any particular limitation on the container used to hold the flux. Any known heatable container can be used in this application without departing from the inventive concept. Examples such as beakers or test tubes are provided for illustrative purposes only and are not intended to limit the scope of protection.

[0026] In this embodiment, the flux level should be at least 2 cm above the top of the tin block to ensure the isolation effect.

[0027] It should be noted that the melting point of tin ingots is approximately 232°C, while the boiling point of flux should be higher than 232°C. Flux provides a stable high-temperature environment for the melting of tin ingots, ensuring uniform heating and allowing the tin ingots to melt and form tin beads. At high temperatures, flux can form a thin film on the tin surface, isolating the molten tin from oxygen in the air, preventing oxidation, and ensuring that the black material appearing on the surface of the tin beads is inherent to the tin itself, rather than a product of reaction with the outside air. Simultaneously, the hygroscopic nature of flux allows it to absorb moisture from the environment and keep the system moist, indirectly reducing the oxidation rate of tin at high temperatures. Furthermore, flux assists in the formation of tin beads, reducing molten tin loss.

[0028] Step S3: Heat the flux to 240℃-290℃ to melt the tin block into tin beads.

[0029] This application does not specifically limit the heating device used in its embodiments. Any known heating device can be used in this application without departing from the inventive concept. Examples such as using a heating platform or heating base as the heating device are merely illustrative and not intended to limit the scope of protection.

[0030] In this embodiment, the flux is heated to 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, or 290°C.

[0031] Understandably, the heating temperature should be higher than the melting point of the tin block and lower than the boiling point of the flux to prevent the flux from evaporating.

[0032] Step S4: Cool the solder balls to room temperature in the flux.

[0033] It should be noted that the room temperature was 23±2℃.

[0034] If black substances are present on the surface of the cooled solder balls, the recycled solder is deemed unusable for production. If no black substances are present on the surface of the cooled solder balls, the recycled solder can be used directly for production. This allows for quick identification of the quality of the recycled solder.

[0035] In one embodiment, the flux is glycerol, diglycerol, sorbitol, polyethylene glycol 200, or polyethylene glycol 400.

[0036] In another embodiment, the flux comprises the following raw materials by weight percentage: 5-15% sodium silicate and 100% glycerol. When heated in the glycerol system, sodium silicate decomposes to form a glassy molten layer rich in silica, uniformly covering the surface of the tin beads, physically isolating the air from the tin and inhibiting the formation of tin oxide. The silicate ions in the silicate can undergo a complexation reaction with tin ions, forming a dense tin-silicate composite film on the tin surface. This film is chemically bonded to the tin surface, improving corrosion resistance, and its structural stability is superior to that of a simple oxide film. The high viscosity of glycerol slows the flow and loss of the silicate molten layer, prolonging the duration of the protective film. Simultaneously, the hydroxyl groups in the glycerol molecules form hydrogen bonds with the metal cations in the silicate, enhancing the adhesion between the film and the tin surface. This can further improve the accuracy of detection.

[0037] It should be noted that the sodium silicate content can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%. Too high a sodium silicate content will result in an excessively thick protective film, interfering with heat transfer. Too low a sodium silicate content will prevent the formation of a complete protective film.

[0038] This application also discloses a method for preparing lead-free solder rods using solder beads, comprising: Step S1: Mix 2-4% Ag by weight, 0.3-0.7% Cu, and the balance tin beads and heat to form a first molten mixture, and make the first molten mixture homogeneous.

[0039] In the embodiments of this application, the content of Ag can be 2wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, 3wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, or 4wt%, and the content of Cu can be 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, or 0.7wt%.

[0040] Step S2: Cast lead-free solder rods using the first molten mixture.

[0041] This application also discloses a method for preparing lead-free solder wire using solder beads, comprising: Step S1: Mix 0.3-0.7% Ag and 0.5-0.9% Cu by weight, with the balance being tin beads, and heat to form a second molten mixture, and then mix the second molten mixture thoroughly.

[0042] In the embodiments of this application, the content of Ag can be 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, or 0.7wt%, and the content of Cu can be 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, or 0.9wt%.

[0043] Step S2: Cast the second molten mixture into a solder bar.

[0044] Step S3: The solder rod is extruded and drawn to form lead-free solder wire.

[0045] In the embodiments of this application, flux is added at a weight ratio of 0, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, or 4wt% during extrusion.

[0046] This application also discloses a method for preparing lead-free tin sheets using tin beads, comprising: Step S1: Mix 2-4% Ag, 0.3-0.7% Cu by weight, with the balance being tin beads, and heat to form a third molten mixture, and then mix the third molten mixture thoroughly.

[0047] In the embodiments of this application, the content of Ag can be 2wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, 3wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, or 4wt%, and the content of Cu can be 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, or 0.7wt%. Step S2: Cast the third molten mixture into a solder bar.

[0048] Step S3: The solder rod is extruded to form a solder sheet.

[0049] Step S4: Apply 0-5% by weight of flux to the surface of the solder sheet and dry it to obtain lead-free solder sheet.

[0050] In this embodiment, flux in weights of 0, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt% is applied to the surface of the solder sheet.

[0051] This application also discloses a method for preparing lead-free solder bars using solder beads, comprising: Step S1: Mix and heat 0-0.7% Ag, 0.3-0.9% Cu, 0-0.1% Ni by weight, with the balance being tin beads, to form a fourth molten mixture, and make the fourth molten mixture homogeneous.

[0052] In the embodiments of this application, the content of Ag can be 0, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, or 0.7wt%; the content of Cu can be 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, or 0.9wt%; and the content of Ni can be 0, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt%. Step S2: Cast lead-free solder bars using the fourth molten mixture. Example Example 1

[0053] A method for detecting recycled tin, comprising: Step S1: Clean the surface of the solder block with alcohol.

[0054] Step S2: Place the tin block in glycerin.

[0055] Step S3: Heat the glycerin to 260°C to melt the tin block into tin beads.

[0056] Step S4: Cool the tin beads in glycerin to room temperature. Example 2

[0057] The difference from Example 1 is that the flux is replaced with diglyceride. Example 3

[0058] The difference from Example 1 is that the flux is replaced with sorbitol. Example 4

[0059] The difference from Example 1 is that the flux is replaced with polyethylene glycol 200. Example 5

[0060] The difference from Example 1 is that the flux is replaced with polyethylene glycol 400. Example 6

[0061] The difference from Example 1 is that a certain amount of glycerol was heated to 150°C, and sodium silicate at a weight ratio of 5 wt% was slowly added to the glycerol under stirring to form mixture A. Mixture A was then cooled to room temperature. Mixture A was used as a flux. Example 7

[0062] The difference from Example 1 is that a certain amount of glycerol was heated to 150°C, and sodium silicate (10 wt%) was slowly added to the glycerol under stirring to form mixture B. Mixture B was then cooled to room temperature. Mixture B was used as a flux. Example 8

[0063] The difference from Example 1 is that a certain amount of glycerol was heated to 150°C, and sodium silicate (15 wt%) was slowly added to the glycerol under stirring to form a mixture C. The mixture C was then cooled to room temperature. Mixture C was used as a flux.

[0064] The quality of recycled tin can be quickly identified by testing the samples using the detection methods shown in Examples 1-8. Figure 2 The presence of black substances on the surface of the first sample indicates that the sample is of poor quality and cannot be used directly in production. Figure 3 The test results show that the surface of the second sample is free of black substances, proving that the quality of the second sample meets the standards and can be used directly in production.

[0065] The implementation principle of this embodiment is as follows: By cleaning the surface of the tin block, impurities adhering to the surface of the recycled tin can be effectively removed, reducing the impact of surface impurities on the test results and improving the accuracy and reliability of the test results. The flux provides a stable high-temperature environment for the melting of the tin block and enables the tin block to be heated uniformly, melting and forming tin beads. At high temperatures, the flux can form a thin film on the tin surface, isolating oxygen in the air from the molten tin, preventing oxidation, and ensuring that the black material on the surface of the tin beads is inherent to the tin itself, rather than being produced by reaction with the outside air. Simultaneously, the hygroscopic nature of the flux allows it to absorb moisture from the environment and keep the system moist, indirectly reducing the oxidation rate of tin at high temperatures. Furthermore, the flux assists in the formation of tin beads, reducing the loss of molten tin. The flux is heated to 240℃-290℃ to melt the tin block into tin beads. The tin beads are then cooled to room temperature in the flux. If black substances are present on the surface of the cooled tin beads, the recycled tin block is considered unusable for production. If no black substance appears on the surface of the cooled tin beads, the recycled tin can be used directly in production. This allows for quick identification of the quality of the recycled tin.

[0066] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting the recovery of tin, characterized in that, The application relates to a method for preparing a lead-free soldering tin product, comprising the following steps: S1, cleaning the surface of a tin block; S2, placing the tin block into a fluxing agent; S3, heating the fluxing agent to 240-290 DEG C to melt the tin block into tin beads; S4, cooling the tin beads in the fluxing agent to room temperature.

2. The method of claim 1, wherein the tin is recovered. The fluxing agent is glycerol, diglycerol, sorbitol, polyethylene glycol 200 or polyethylene glycol 400.

3. The method of claim 1, wherein the tin is recovered. The fluxing agent comprises the following raw materials in percentage by weight: sodium silicate 5-15%, glycerol 100%.

4. The method of claim 1, wherein the tin is recovered. In step S2, the liquid level of the fluxing agent is higher than the top of the tin block by more than 2 cm.

5. A method for producing a lead-free tin rod using the tin bead according to any one of claims 1 to 4, characterized by, The application relates to a method for preparing a lead-free soldering tin product, comprising the following steps: S1, mixing and heating Ag 2-4% by weight, Cu 0.3-0.7% by weight and the rest tin beads into a first molten-state mixture, and uniformly mixing the first molten-state mixture; S2, using the first molten-state mixture to cast the lead-free soldering tin rod.

6. A method for producing a lead-free tin wire using the tin bead according to any one of claims 1 to 4, characterized by, The application relates to a method for preparing a lead-free soldering tin product, comprising the following steps: S1, mixing and heating Ag 0.3-0.7% by weight, Cu 0.5-0.9% by weight and the rest tin beads into a second molten-state mixture, and uniformly mixing the second molten-state mixture; S2, using the second molten-state mixture to cast the soldering tin rod; S3, extruding and drawing the soldering tin rod to form the lead-free soldering tin wire.

7. The method of claim 6, wherein the lead-free tin wire is prepared by a process comprising the steps of: In step S3, when extruding, 0-4% by weight of a fluxing agent is added. ​ 8. A method for producing a lead-free tin sheet using the tin bead according to any one of claims 1 to 4, characterized by, The application relates to a method for preparing a lead-free soldering tin product, comprising the following steps: S1, mixing and heating Ag 2-4% by weight, Cu 0.3-0.7% by weight and the rest tin beads into a third molten-state mixture, and uniformly mixing the third molten-state mixture; S2, using the third molten-state mixture to cast the soldering tin rod; S3, extruding the soldering tin rod to form a soldering tin sheet; S4, coating 0-5% by weight of a fluxing agent on the surface of the soldering tin sheet, and drying to obtain the lead-free soldering tin sheet.

9. A method for producing a lead-free tin bar using the tin bead according to any one of claims 1 to 4, characterized by, The application relates to a method for preparing a lead-free soldering tin product, comprising the following steps: S1, mixing and heating Ag 0-0.7% by weight, Cu 0.3-0.9% by weight, Ni 0-0.1% by weight and the rest tin beads into a fourth molten-state mixture, and uniformly mixing the fourth molten-state mixture; S2, using the fourth molten-state mixture to cast the lead-free soldering tin rod.

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