Green recovery method for automobile circuit board

Abstract

The invention discloses a green recycling method for an automobile circuit board. The green recycling method comprises the following steps: S1, carrying out preliminary physical cutting and crushing treatment on a waste PCB (Printed Circuit Board); and S2, the crushed materials are subjected to metal and nonmetal component screening. The method is scientific in principle, simple in process method and easy to implement, firstly, the circuit board is cut and smashed into small fragments, then slurry is formed by adding water, finally, metal and nonmetal parts in the circuit board are separated through a laboratory flotation column, and the purpose of green recycling is achieved. The invention provides a scientific and green PCB recovery technology, metal and non-metal materials in the waste PCB are separated and recovered, the cost is low, the efficiency is high, and the method has important significance on environmental protection and energy regeneration.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and energy regeneration technology, and specifically relates to a green recycling method for automotive circuit boards. Background Technology

[0002] With the rapid development of the automotive industry, the recycling volume of waste motor vehicles is growing exponentially. Printed circuit boards (PCBs) are an important component of in-vehicle electronic products, containing both organic and inorganic materials. When waste PCBs are landfilled or incinerated, they generate large amounts of pollutants, causing environmental damage. Furthermore, PCBs contain a significant amount of rare and precious metals, possessing enormous recycling potential. Therefore, developing scientific and green PCB recycling technologies to separate metallic and non-metallic materials from waste PCBs is of great significance for environmental protection and energy regeneration. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a green recycling method for automotive circuit boards that is energy-saving, environmentally friendly, easy to implement, low-cost, and highly efficient.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a green recycling method for automotive circuit boards, comprising the following steps: S1. Perform preliminary physical cutting and shredding of waste PCBs; S2. Screen the pulverized material for metallic and non-metallic components.

[0005] Step S1 specifically includes the following sub-steps: S1-1: Manually remove screws, large heat sinks and other steel and aluminum components from the PCB, while also removing the battery, electrolyte and other toxic components; S1-2: A cutting machine driven by a three-phase motor is used to cut the PCB into large pieces of 12-18cm, reducing the size of the large circuit board to a size suitable for subsequent processing. S1-3: First, use a shredder to break down large pieces into medium pieces of 4-6cm. Then, use a shredder driven by a 5HP unidirectional motor with a 1.9cm sieve to sieve again, breaking down the medium pieces into small pieces smaller than 1.9cm.

[0006] Step S2 specifically includes the following sub-steps: S2-1: Prepare a slurry by mixing small fragments into water at a ratio of 1.25 wt.%; S2-2: Confirm that the flotation column body, bubble generator, slurry circulation pump, tailings discharge valve and automatic control loop are in normal working condition. The automatic control loop includes pressure sensor, controller and peristaltic feed pump. S2-3: The prepared slurry with a solid concentration of 1.25 wt.% is fed into the upper part of the flotation column through a peristaltic feed pump at a stable flow rate; S2-4: Start the flotation column to carry out flotation operations, and finally obtain metal concentrate by continuously discharging from the tailings pipe at the bottom of the flotation column.

[0007] The specific process of flotation operation in step S2-3 is as follows: (1) Initialization of water level and foam layer: The injected slurry is used to establish the initial liquid level in the flotation column, and then the bubble generator is started to form a stable initial foam layer at the top of the flotation column body; (2) The air flow rate injected into the bubble generator at the bottom of the flotation column is precisely controlled by a mass flow meter, and the apparent air velocity is adjusted and stabilized within the optimized range of 0.10 to 0.75 cm / s; the specific set value needs to be optimized in real time according to the particle size and metal content of the material. (3) The pressure at the interface between the foam layer and the slurry is monitored in real time by a pressure sensor. The pressure signal is fed back to the controller, which automatically adjusts the opening of the tailings discharge valve or the speed of the feed pump to stabilize the foam layer depth at a set value of 10-30 cm. A stable foam layer is a prerequisite for ensuring continuous and stable separation. (4) Because the non-metallic surface is naturally hydrophobic, it can firmly adhere to the surface of the bubble when it collides with the bubble. The bubble carries these hydrophobic particles upward, passes through the slurry zone, and finally converges at the top of the flotation column to form a foam product (Concentrate), which is scraped off or overflowed as a non-metallic concentrate. The metallic component is naturally hydrophilic and is difficult to adhere to the bubble. The metal settles downward in the slurry due to gravity, or is continuously discharged from the tailings pipe at the bottom of the flotation column with the downward flowing water, thus obtaining a metallic concentrate.

[0008] Compared with related technologies, the present invention has the following beneficial effects by adopting the above technical solution: This invention is based on sound principles, employs a simple and easy-to-implement process. First, the circuit board is cut and crushed into small pieces. Then, water is added to form a slurry. Finally, a laboratory flotation column is used to separate the metallic and non-metallic components, achieving green recycling. This invention presents a scientific and green PCB recycling technology that separates and recycles metallic and non-metallic materials from waste PCBs. It is low-cost, highly efficient, and of great significance for environmental protection and energy regeneration. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the present invention, which uses a flotation column to separate metallic and non-metallic materials. Detailed Implementation

[0010] A green recycling method for automotive circuit boards includes the following steps: S1. Perform preliminary physical cutting and shredding of waste PCBs; S2. Screen the pulverized material for metallic and non-metallic components.

[0011] Step S1 specifically includes the following sub-steps: S1-1: Manually remove screws, large heat sinks and other steel and aluminum components from the PCB, while also removing the battery, electrolyte and other toxic components; S1-2: A cutting machine driven by a three-phase motor is used to cut the PCB into large pieces of 12-18cm, reducing the size of the large circuit board to a size suitable for subsequent processing. S1-3: First, use a shredder to break down large pieces into medium pieces of 4-6cm. Then, use a shredder driven by a 5HP unidirectional motor with a 1.9cm sieve to sieve again, breaking down the medium pieces into small pieces smaller than 1.9cm.

[0012] Step S2 specifically includes the following sub-steps: S2-1: Prepare a slurry by mixing small fragments into water at a ratio of 1.25 wt.%; S2-2: Confirm that the flotation column body, bubble generator, slurry circulation pump, tailings discharge valve and automatic control loop are in normal working condition. The automatic control loop includes pressure sensor, controller and peristaltic feed pump. S2-3: The prepared slurry with a solid concentration of 1.25 wt.% is fed into the upper part of the flotation column through a peristaltic feed pump at a stable flow rate; S2-4: Start the flotation column to carry out flotation operations, and finally obtain metal concentrate by continuously discharging from the tailings pipe at the bottom of the flotation column.

[0013] like Figure 1 As shown, the specific process of flotation operation by the flotation column in step S2-3 is as follows: (1) Initialization of water level and foam layer: The injected slurry is used to establish the initial liquid level in the flotation column, and then the bubble generator is started to form a stable initial foam layer at the top of the flotation column body; (2) The air flow rate injected into the bubble generator at the bottom of the flotation column is precisely controlled by a mass flow meter, and the apparent air velocity is adjusted and stabilized within the optimized range of 0.10 to 0.75 cm / s; the specific set value needs to be optimized in real time according to the particle size and metal content of the material. (3) The pressure at the interface between the foam layer and the slurry is monitored in real time by a pressure sensor. The pressure signal is fed back to the controller, which automatically adjusts the opening of the tailings discharge valve or the speed of the feed pump to stabilize the foam layer depth at a set value of 10-30 cm. A stable foam layer is a prerequisite for ensuring continuous and stable separation. (4) Because the non-metallic surface is naturally hydrophobic, it can firmly adhere to the surface of the bubble when it collides with the bubble. The bubble carries these hydrophobic particles upward, passes through the slurry zone, and finally converges at the top of the flotation column to form a foam product (Concentrate), which is scraped off or overflowed as a non-metallic concentrate. The metallic component is naturally hydrophilic and is difficult to adhere to the bubble. The metal settles downward in the slurry due to gravity, or is continuously discharged from the tailings pipe at the bottom of the flotation column with the downward flowing water, thus obtaining a metallic concentrate.

[0014] The above embodiments illustrate the basic principles and features of the present invention, but are merely preferred embodiments and are not limited to these embodiments. Those skilled in the art, inspired by this patent, can make many modifications and improvements without departing from the spirit and scope of the claims, all of which fall within the scope of protection of the present invention. Therefore, the scope of this patent and its protection should be determined by the appended claims.

Claims

1. A method for green recycling of automotive circuit boards, characterized in that: The method comprises the following steps: S1, preliminary physical cutting and crushing treatment is performed on the waste PCB; S2, the crushed materials are screened for metal and non-metal components.

2. The green recycling method of automobile circuit board according to claim 1, characterized in that: Step S1 specifically comprises the following steps: S1-1: manually disassemble the screws, large-volume heat sinks and other steel and aluminum components on the PCB, and disassemble the battery and electrolyte and other toxic components; S1-2: use a cutting machine driven by a three-phase motor to cut the PCB into large pieces of 12-18 cm, so that the large circuit board is reduced to a size suitable for subsequent processing; S1-3: first use a crusher to break the large pieces into medium pieces of 4-6 cm, and then use a 5HP single motor driven crusher to cooperate with a 1.9 cm screen to sieve again, and the medium pieces are broken into small pieces of less than 1.9 cm.

3. The green recycling method of automobile circuit board according to claim 2, characterized in that: Step S2 specifically comprises the following steps: S2-1: mix the small pieces into water at a proportion of 1.25wt.% to prepare a slurry; S2-2: confirm that the flotation column body, bubble generator, slurry circulating pump, tailings discharge valve and automatic control loop are in normal working condition, and the automatic control loop includes a pressure sensor, a controller and a peristaltic feed pump; S2-3: feed the prepared slurry with a solid concentration of 1.25wt.% into the upper part of the flotation column through the peristaltic feed pump at a stable flow rate; S2-4: start the flotation column for flotation operation, and finally continuously discharge the metal concentrate from the tailings pipe at the bottom of the flotation column body.

4. The green recycling method of automobile circuit board according to claim 3, characterized in that: The specific process of the flotation column for flotation operation in step S2-3 is as follows: (1) water level and foam layer initialization: the injected slurry establishes an initial liquid level in the flotation column, and then the bubble generator is started to form a stable initial foam layer at the top of the flotation column body; (2) accurately control the air flow rate of the bubble generator injected into the bottom of the flotation column body through a mass flow meter, and adjust and stabilize the apparent air speed in the optimal range of 0.10 to 0.75 cm / s; the specific setting value needs to be optimized in real time according to the particle size and metal content of the material; (3) monitor the pressure of the foam layer and slurry interface in real time through the pressure sensor, and feed the pressure signal back to the controller, which automatically adjusts the opening degree of the tailings discharge valve or the speed of the feed pump to stabilize the foam layer depth at a set value of 10-30 cm; a stable foam layer is a prerequisite for continuous and stable separation; (4) because the non-metal surface is naturally hydrophobic, when it collides with the bubble, it can firmly adhere to the bubble surface, and the bubble carries these hydrophobic particles upward, passes through the slurry zone, and finally converges at the top of the flotation column body to form a foam product, which is scraped out or overflowed as a non-metal concentrate; the metal component surface is naturally hydrophilic and difficult to adhere to the bubble, and the metal sinks in the slurry due to gravity or flows downward with the water flow, and is continuously discharged from the tailings pipe at the bottom of the flotation column body, thereby obtaining a metal concentrate.

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