Waste solder paste environment-friendly treatment device and treatment method based on gradient temperature control

Abstract

The invention discloses a waste solder paste environment-friendly treatment device and treatment method based on gradient temperature control, and belongs to the technical field of waste solder paste recycling treatment. Waste solder paste is put into the waste solder paste environment-friendly treatment device, a melting chamber is subjected to two-stage gradient heating through a heating device, and scaling powder and metal powder in the waste solder paste are separated; the method comprises the following steps: firstly heating to melt a soldering flux in the waste solder paste, opening a vibration module to prevent filter screens from blocking holes, enabling the soldering flux to flow into a heat preservation collection chamber through a double-layer filter screen, and blocking unmelted solid metal powder in the waste solder paste on the double-layer filter screen; a scaling powder outlet control valve is opened, and the liquid scaling powder is led into a collector; and then the solid metal powder is heated and melted, after the melted metal liquid is vibrated to fall into the heat preservation collecting chamber, a metal liquid outlet valve is opened, and the metal liquid is led out to be cast into an ingot. Through gradient temperature control, step-by-step separation of the soldering flux and the alloy solder in the waste soldering paste is achieved, and high efficiency and environmental protection are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste solder paste recycling and treatment, and particularly relates to an environmentally friendly and efficient waste solder paste treatment device and a treatment method thereof. Background Art

[0002] With the rapid development of the electronic product manufacturing industry, more than 500,000 tons of waste solder paste are generated globally every year, which requires a great deal of effort to handle. Traditional waste solder paste treatment mostly uses the direct melting method. For example, in CN108823413A, the flux and solder are synchronously treated at a high temperature of 300°C, resulting in the pyrolysis of components such as rosin and organic acids to generate a large amount of waste gas containing benzene series and dioxins. According to statistics, 8.6 kg of VOCs are generated per ton of waste solder paste treatment, and RTO incineration equipment worth more than 2 million yuan needs to be supported. The chemical dissolution method for treating waste solder paste (such as CN114289480) is to soak and separate the waste solder paste with an organic solution. Although it can reduce soot, it will generate a large amount of high-COD wastewater and the treatment cost is relatively high. Through experimental tests, it is found that the existing treatment technologies mainly have the following technical bottlenecks: the temperature ranges of the flux vapor phase and the molten solder overlap (120 - 200°C), resulting in the synchronous gasification-liquefaction phenomenon, and further causing the flux vapor phase and the molten solder phase to be difficult to separate, and the treatment efficiency is low. In addition, most of the existing technologies still rely on manual operation, which has serious safety hazards. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems of serious waste gas pollution, high treatment cost, low treatment efficiency, and high dependence on manual labor existing in the above-mentioned existing technologies, and to provide an automatic treatment device and a treatment method thereof that can effectively separate the solder and flux in the waste solder paste through gradient temperature control.

[0004] The technical solution adopted by the present invention is as follows: An environmentally friendly waste solder paste treatment device based on gradient temperature control, including a melting chamber provided with a heating device, a heat preservation collection chamber provided with a heat preservation layer, a double-layer filter screen arranged between the melting chamber and the heat preservation collection chamber, a vibration module arranged between the double-layer filter screens, a flux control valve and a metal liquid control valve arranged at the bottom of the side wall of the heat preservation collection chamber, a flux collector and a metal automatic casting module respectively arranged at the flux outlet and the metal liquid outlet, and the bottom of the heat preservation collection chamber is a conical bottom with the cone top upward.

[0005] Further, the double-layer filter screen is a double-layer filter screen sintered with tungsten wire, the aperture of the upper filter screen is 80 - 120 μm, and the aperture of the lower filter screen is 5 - 25 μm; the vibration module is a piezoelectric vibration module with a vibration frequency of 20 - 40 kHz.

[0006] The treatment method of the environmentally friendly waste solder paste treatment device of the present invention is as follows: Put the waste solder paste into the melting chamber, and use the heating device to raise the temperature of the melting chamber in two - stage gradient, so as to separate the flux and metal powder in the waste solder paste. First, heat and keep warm to melt the flux in the waste solder paste first, and it flows into the heat - preservation collection chamber through the double - layer filter screen. Turn on the vibration module to prevent the filter holes from being blocked. The solid metal powder in the waste solder paste that has not melted is blocked on the double - layer filter screen. First, open the flux control valve to lead out the liquid flux to the flux collector arranged below the flux outlet. Then, heat the melting chamber until the solid metal powder melts, and the molten metal liquid flows into the heat - preservation collection chamber. Open the metal liquid control valve to divert the metal liquid to the metal automatic casting module to complete the casting.

[0007] Further, for the two - stage gradient heating, the melting chamber is first heated to 120 - 130 °C and kept warm for 80 - 120 minutes to completely melt the flux in the waste solder paste and let it flow out of the heat - preservation collection chamber. Then, the heating cylinder is heated to 180 °C - 360 °C to completely melt the metal powder in the waste solder paste.

[0008] The present invention has the following beneficial effects: 1. The processing device of the present invention forms an upper - layer heating and melting area and a lower - layer heat - preservation area by setting the upper - layer heating cylinder and the lower - layer heat - preservation collection chamber. Through the gradient temperature control of the upper - layer heating and melting area and the dynamic filtering component composed of the double - layer filter screen and the vibration module, the sequential and efficient separation of solder and flux is realized. And through the flux outlet, the metal liquid outlet and the collection devices respectively arranged at the flux outlet and the metal liquid outlet, the separation process of solder and flux is more efficient. At the same time, it is convenient for the recycling treatment of waste flux and avoids the loss of valuable metals.

[0009] 2. Adopt a double - layer tungsten - wire sintered filter screen, and the bottom aperture of the lower - layer filter screen is smaller than that of the upper - layer filter screen, which can effectively prevent the solid metal powder particles in the solder paste from entering the heat - preservation chamber during the melting stage of the flux, avoiding the loss of valuable metals. At the same time, integrate the piezoelectric vibration module, which can effectively prevent the filter holes from being blocked, improve the stability and reliability of the filtering component, and reduce the maintenance cost.

[0010] 3. Set an electric heating device inside the wall of the heating cylinder and set a heat - preservation layer outside the heat - preservation collection chamber, which can accurately control the heating temperature, effectively reduce heat loss and lower energy consumption.

[0011] 4. The processing method is simple and efficient, does not require adding any auxiliary agents, nor does it require combustion. The processing process is clean and environmentally friendly, with low processing costs, extremely low emissions of waste gas and waste liquid, meeting the environmental protection requirements. Description of the Drawings

[0012] Figure 1 It is a structural schematic diagram of the processing device of the present invention; Figure 2It is the temperature control curve graph of the two-stage temperature control program adopted by the processing method of Embodiment 1 of the present invention; Figure 3 It is the temperature control curve graph of the two-stage temperature control program adopted by the processing method of Embodiment 2 of the present invention; Figure 4 It is the temperature control curve graph of the two-stage temperature control program adopted by the processing method of Embodiment 3 of the present invention; Figure 5 It is the temperature control curve graph of the two-stage temperature control program adopted by the processing method of Embodiment 4 of the present invention. Detailed implementation manners

[0013] The content of the present invention will be further elaborated below in conjunction with the specification drawings and embodiments.

[0014] As Figure 1 shown, an environmentally friendly waste solder paste treatment device based on gradient temperature control includes a melting chamber 1, a heating device 2 arranged on the side wall of the melting chamber, a double-layer filter screen 3 arranged between the melting chamber and the heat preservation collection chamber, a vibration module 4 arranged between the double-layer filter screens, a heat preservation collection chamber 5 arranged below the filter screen, a heat preservation layer 6 arranged on the side wall of the heat preservation collection chamber, a flux control valve 9 and a metal liquid control valve 9 arranged at the bottom of the side wall of the heat preservation collection chamber, a flux collector 10 and a metal automatic casting module 11 respectively arranged at the flux outlet and the metal liquid outlet. The bottom 7 of the heat preservation collection chamber is a conical bottom with the cone top upward, which can prevent the melted flux and metal liquid solder from staying at the bottom of the device. The device is a SUS304 stainless steel double-layer hollow shell, and the power of the interlayer heating device is 10 - 50 kW. The treatment device is provided with an automatic control system, which adopts PID to accurately control the heating temperature and the heat preservation temperature, and at the same time has a fault alarm and an emergency stop function. The provided heat preservation layer 6 helps the liquid flux and metal liquid to maintain good fluidity and flow out of the heat preservation collection chamber smoothly. A flux collector 10 is arranged below the flux outlet 8, and a metal liquid container or a metal automatic casting module 11 is arranged below the metal liquid outlet 9. The metal automatic casting module is an existing technical device.

[0015] The double-layer filter screen 3 is a double-layer filter screen sintered with tungsten wire. The pore diameter of the upper filter screen 3a is 80 - 120 μm, and the pore diameter of the lower filter screen 3b is 5 - 25 μm. The vibration module 4 is a piezoelectric vibration module with a vibration frequency of 20 - 40 kHz. The heating device 2 can be an electric heating device, or can adopt a high-temperature heat-conducting oil heating method or other heating methods of existing technologies.

[0016] The treatment method of the environmentally friendly waste solder paste treatment device of the present invention is as follows: Put the waste solder paste into the melting chamber 1, start the two-stage temperature control program, and perform gradient heating through the heating device 2. Use PID for precise temperature control. In the first stage of heating, first melt the flux in the waste solder paste, which then flows into the insulation chamber through the double-layer filter screen. Control the vibration frequency of the vibration module at 20 - 40 kHz, open the control valve of the liquid flux outlet 8, and the liquid flux flows into the flux collector 10. After the flux separation is complete, close the control valve of the flux outlet, and move the flux collector to the designated area for further processing. After the liquid flux collection is completed, enter the second stage of heating. Melt the metal powder in the waste solder paste and let it flow into the insulation collection chamber 5 through the double-layer filter screen 3. The vibration module 4 vibrates at a vibration frequency of 20 - 40 kHz to prompt the metal liquid to enter the insulation collection chamber faster and more thoroughly. Open the control valve of the metal liquid outlet, and the metal liquid flows into the metal liquid container, where it is cast into tin solder ingots to achieve metal recycling. It is also possible to use the metal liquid collection and automatic pouring device 11 of the existing technology to collect the metal liquid from the metal liquid outlet and directly cast it into tin solder ingots.

[0017] Example 1 Using the treatment device as Figure 1 shown to treat Sn42Bi58 waste solder paste, put the Sn42Bi58 waste solder paste into the melting chamber 1, and start the two-stage temperature control program as Figure 2 shown. Gradually increase the temperature of the melting chamber through the heating device 2. In the first stage of heating, increase the temperature at a rate of 12 °C / min to 120 °C and keep it warm for 100 minutes. The flux in the waste solder paste melts first due to heat and flows into the insulation chamber through the double-layer filter screen. Control the vibration frequency of the vibration module at 20 kHz, open the control valve of the liquid flux outlet 8, and the liquid flux flows into the flux collector 10. After the flux separation is complete, close the control valve of the flux outlet, and move the flux collector to the designated area for further processing. After the liquid flux collection is completed, enter the second stage of heating. Increase the temperature of the melting chamber at a rate of 12 °C / min to 180 °C and then keep it warm. The metal powder in the waste solder paste starts to melt and flows into the insulation collection chamber 5 through the double-layer filter screen 3. The vibration module 4 vibrates at a vibration frequency of 20 kHz, and the metal liquid enters the insulation collection chamber 5. Open the control valve 9 of the metal liquid outlet, and the metal liquid flows into the metal liquid container of the metal liquid collection and automatic pouring device 11 and is directly cast into tin solder ingots.

[0018] Example 2 Using the treatment device as Figure 1 shown to treat rosin-based waste solder paste Sn63Pb37, put the Sn63Pb37 waste solder paste into the melting chamber 1, and start as Figure 3The two-stage temperature control program shown heats the melting chamber in a gradient manner through the heating device 2. In the first stage of heating, it is heated at a rate of 10 °C / min to 120 °C and kept warm for 100 minutes. The flux in the waste solder paste is first melted by heat, flows through the double-layer filter screen into the heat preservation chamber. The vibration frequency of the vibration module is controlled at 30 kHz, the control valve of the flux outlet 8 for the liquid flux is opened, and the liquid flux flows into the flux collector 10. After the flux separation is completed, the control valve of the flux outlet is closed, and the flux collector is moved to the designated area for treatment. After the collection of the liquid flux is completed, it enters the second stage of heating. The melting chamber is heated at a rate of 10 °C / min to 225 °C and then kept warm. The metal powder in the waste solder paste starts to melt and flows through the double-layer filter screen 3 into the heat preservation collection chamber 5. The vibration module 4 vibrates at a vibration frequency of 30 kHz, and the metal liquid enters the heat preservation collection chamber 5. The control valve 9 of the metal liquid outlet is opened, and the metal liquid flows into the metal liquid container of the metal liquid collection automatic pouring device 11 and is directly poured into solder ingots.

[0019] Example 3 Using the method of Figure 1 processing the rosin-based waste solder paste SnAg3.0Cu0.5 with the processing device shown, the SnAg3.0Cu0.5 waste solder paste is put into the melting chamber 1, and start as Figure 4 The two-stage temperature control program shown heats the melting chamber in a gradient manner through the heating device 2. In the first stage of heating, it is heated at a rate of 10 °C / min to 125 °C and kept warm for 100 minutes. The flux in the waste solder paste is first melted by heat, flows through the double-layer filter screen into the heat preservation chamber. The vibration frequency of the vibration module is controlled at 40 kHz, the control valve of the flux outlet 8 for the liquid flux is opened, and the liquid flux flows into the flux collector 10. After the flux separation is completed, the control valve of the flux outlet is closed, and the flux collector is moved to the designated area for treatment. After the collection of the liquid flux is completed, it enters the second stage of heating. The melting chamber is heated at a rate of 10 °C / min to 255 °C and then kept warm. The metal powder in the waste solder paste starts to melt and flows through the double-layer filter screen 3 into the heat preservation collection chamber 5. The vibration module 4 vibrates at a vibration frequency of 30 kHz, and the metal liquid enters the heat preservation collection chamber 5. The control valve 9 of the metal liquid outlet is opened, and the metal liquid flows into the metal liquid container of the metal liquid collection automatic pouring device 11 and is directly poured into solder ingots.

[0020] Example 4 Using the method of Figure 1 processing the rosin-based waste solder paste SnPb92.5Ag2.5 with the processing device shown, the SnPb92.5Ag2.5 waste solder paste is put into the melting chamber 1, and start as Figure 5The two-stage temperature control program shown heats the melting chamber in a gradient manner through the heating device 2. In the first stage of heating, the temperature is raised to 130 °C at a rate of 11 °C / min and held for 100 minutes. The flux in the waste solder paste is first melted by heat, flows through the double-layer filter screen into the heat preservation chamber. The vibration frequency of the vibration module is controlled at 40 kHz, the control valve of the flux outlet 8 is opened, and the liquid flux flows into the flux collector 10. After the flux separation is completed, the control valve of the flux outlet is closed, and the flux collector is moved to the designated area for treatment. After the liquid flux collection is completed, it enters the second stage of heating. The melting chamber is heated to 360 °C at a rate of 10 °C / min and then held. The metal powder in the waste solder paste starts to melt and flows through the double-layer filter screen 3 into the heat preservation and collection chamber 5. The vibration module 4 vibrates at a vibration frequency of 30 kHz, and the metal liquid enters the heat preservation and collection chamber 5. The control valve 9 of the metal liquid outlet is opened, and the metal liquid flows into the metal liquid container of the metal liquid collection and automatic pouring device 11 and is directly poured into a tin solder ingot.

[0021] The present invention scientifically adopts gradient heating to phase-separate the waste solder paste. After the separation of the flux and the metal powder is completed at about 120 °C, the melting temperature of the metal powder is set to melt it, realizing the efficient recycling of the flux and the metal components. And no chemical agents are added during the treatment process, nor is high-temperature smelting required. Verified by experiments, the treatment device and method of the present invention have outstanding environmental protection effects and economic benefits. Compared with the traditional direct smelting method, the VOCs emission reduction reaches 80%-90%, and the generation amount of dioxins is lower than the detection limit (0.1 ng-TEQ / m³). The total cost of treating 1 ton of waste solder paste by the present invention is only about 600-1000 yuan, while the cost of the traditional treatment method is high. Among them, the chemical dissolution method is about 5000-10000 yuan / ton, and the direct smelting method is about 8000-15000 yuan / ton. In addition, the method of the present invention has less manual intervention and can greatly reduce the occupational hazards to the operators.

Claims

1. A device for environmentally friendly treatment of waste solder paste based on gradient temperature control, characterized in that: The invention comprises a melting chamber (1) provided with a heating device (2), a heat-insulating collection chamber (5) provided with a heat-insulating layer (6), a double-layer filter screen (3) provided between the melting chamber and the heat-insulating collection chamber, a vibration module (4) provided between the double-layer filter screen, a flux control valve (8) and a molten metal control valve (9) provided at the bottom of the side wall of the heat-insulating collection chamber, a flux collector (10) and a metal automatic pouring module (11) provided at the flux outlet and the molten metal outlet, respectively, wherein the bottom of the heat-insulating collection chamber is a conical bottom (7) with the top of the cone facing upward; The double-layer filter is a double-layer filter sintered with tungsten wire, the pore size of the upper filter is 80-120 μm, and the pore size of the lower filter is 5-25 μm; The vibration module (4) is a piezoelectric vibration module with a vibration frequency of 20-40 kHz.

2. The method for treating waste solder paste by using the device for environmentally friendly treatment of waste solder paste based on gradient temperature control according to claim 1 is characterized in that: The method is as follows: waste solder paste is put into a melting chamber (1), and the melting chamber is heated in two stages by a heating device (2) to separate the flux and metal powder in the waste solder paste; firstly, heating and heat preservation are performed to melt the flux in the waste solder paste first, and then the flux flows into a heat preservation collection chamber (5) through a double-layer filter (3); a vibration module (4) is started to prevent the filter from being blocked, and the solid metal powder in the waste solder paste that has not yet melted is blocked on the double-layer filter; firstly, a flux control valve (8) is opened to lead the liquid flux to a flux collector (10) arranged below the flux outlet; then, the melting chamber is heated until the solid metal powder is melted, and the molten metal liquid flows into the heat preservation collection chamber; and the metal liquid control valve (9) is opened to lead the metal liquid to a metal automatic pouring module (11) to complete the pouring.

3. The processing method according to claim 2, characterized in that: The two-stage gradient heating is to first heat the melting chamber (1) to 120-130°C and keep it warm for 80-120 minutes, so that all the flux in the waste solder paste melts and flows out of the heat-insulating collection chamber (5), and then heat the melting chamber (1) to 180°C-360°C to melt all the metal powder in the waste solder paste.

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