Method for separating and recycling each component material in waste printed circuit boards by using near-critical water

A waste circuit board, near-critical water technology, applied in recycling technology, electronic waste recycling, solid waste removal, etc., can solve problems such as reducing fuel quality, corroding treatment equipment, polluting the environment, etc. Effect of carbonization rate

Active Publication Date: 2014-07-30
HARBIN INST OF TECH
10 Cites 10 Cited by

AI-Extracted Technical Summary

Problems solved by technology

However, during the pyrolysis process, the circuit board will generate more toxic and harmful substances such as masking smoke, elemental bromine an...
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Abstract

The invention discloses a method for separating and recycling each component material in waste printed circuit boards by using near-critical water. According to the method, the near-critical water is taken as a reaction medium, and the waste printed circuit boards are separated and recycled by regulating and controlling the temperature and the reaction time to realize complete separation of a copper foil, glass fiber cloth and a resin substrate under the existence of different catalysts, wherein the recycled copper coil and glass fiber cloth can be further reused directly; the resin substrate exists in the form of decomposed oil; major components of the resin substrate are phenol and phenol derivatives which can be further purified into chemical raw materials for application. Thus, the method plays a role in promoting the recycling of the waste printed circuit boards, is an environmentally-friendly, easy-to-operate and efficient technology, and is very wide in application prospect.

Application Domain

Technology Topic

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  • Method for separating and recycling each component material in waste printed circuit boards by using near-critical water
  • Method for separating and recycling each component material in waste printed circuit boards by using near-critical water
  • Method for separating and recycling each component material in waste printed circuit boards by using near-critical water

Examples

  • Experimental program(3)

Example Embodiment

[0029] Example 1
[0030] Such as figure 1 As shown, a method for separating and recycling various component materials of waste circuit boards with near-critical water mainly includes four processes: pretreatment, near-critical water treatment, extraction of decomposition products of resin matrix, copper foil and fiber woven fabric The specific steps are as follows:
[0031] (1) Pretreatment: Disassemble and separate the main board and components of the waste circuit board, and classify the disassembled components before processing them separately, and then cut the main board into cubes with a size of 1.0cm×1.0cm.
[0032] (2) Near-critical water treatment: According to the feed ratio of 1:5 (g/ml), add 1g of the cut waste circuit board main board and 5ml of water to the reactor, and then add 0.02g of hydrochloric acid (HCl) as a catalyst , Seal the reactor, turn on the power to start heating, the reaction temperature is 300 ℃, after the temperature stabilizes, start timing, the reaction time is maintained for 120 minutes, and the pressure in the kettle is maintained above 4.5 MPa.
[0033] (3) Extraction of decomposition products of the resin matrix: After the near-critical water treatment, turn off the power, take out the reaction kettle and cool it to room temperature with tap water to transfer the reaction products, the aqueous decomposition liquid and solid phase products obtained, and then extract with ethyl acetate The aqueous phase decomposition liquid is mainly phenol and phenol derivatives (such as figure 2 As shown), the fiber fabric in the solid phase product obtained at the same time has obvious delamination, and the copper foil is easy to peel off (such as image 3 Shown)
[0034] (4) Recovery of copper foil and glass fiber cloth: the solid phase product (glass fiber cloth and copper foil) obtained in step (3) is soaked in acetone for 24 hours, then washed with distilled water 5 times, and placed in an oven at 100°C Dry for 3h in the middle to obtain the separation product of copper foil and glass fiber cloth (such as Figure 4-6 Shown).

Example Embodiment

[0035] Example 2
[0036] A method of using near-critical water to separate and recycle the components of waste circuit boards mainly includes the following steps:
[0037] (1) Pretreatment: Disassemble and separate the main board and components of the used circuit board, and classify the disassembled components before processing separately, and then cut the main board into cubes of 2cm×2cm.
[0038] (2) Near-critical water treatment: According to the feed ratio of 1:15 (g/ml), add 1g of the cut waste circuit board main board and 15ml of water to the reactor, and then add 0.02g of sodium hydroxide (NaOH) , The reaction kettle is sealed, the power is turned on to start heating, and the reaction temperature is 320°C. After the temperature stabilizes, start timing, and the reaction time is maintained for 150 minutes. The pressure in the reactor is monitored by a pressure gauge connected to it, and the pressure in the reactor remains above 7.0 MPa during the reaction.
[0039] (3) Extraction of decomposition products of the resin matrix: After the near-critical water treatment, turn off the power, take out the reaction kettle and cool it to room temperature with tap water to transfer the reaction products, the aqueous decomposition liquid and solid phase products obtained, and then extract with ethyl acetate The aqueous phase decomposition liquid is mainly phenol and phenol derivatives (such as figure 2 As shown), the fiber fabric in the solid phase product obtained at the same time has obvious delamination, and the copper foil is easy to peel off (such as image 3 Shown).
[0040] (4) Recovery of copper foil and glass fiber cloth: the solid phase product (glass fiber cloth and copper foil) obtained in step (3) is soaked in acetone for 24 hours, then washed with distilled water 5 times, and placed in a temperature of 100 ℃ Dry in an oven for 3 hours, and finally obtain the separation product of copper foil and glass fiber cloth (such as Figure 4 , 5 with Image 6 Shown).

Example Embodiment

[0041] Example 3
[0042] A method of using near-critical water to separate and recycle the components of waste circuit boards mainly includes the following steps:
[0043] (1) Pretreatment: Disassemble and separate the main board and components of the used circuit board, and classify the disassembled components before processing separately, and then cut the main board into cubes with a size of 0.5cm×0.5cm.
[0044] (2) Near-critical water treatment: According to the feed ratio of 1:10 (g/ml), add 1g of the cut waste circuit board main board and 10ml of water into the reactor, and then add 0.02 g of sodium carbonate (Na 2 CO 3 ) As a catalyst, the reactor is sealed, the power is turned on, and the heating is started. The reaction temperature is 280°C. After the temperature stabilizes, start timing and the reaction time is maintained for 150 minutes. The pressure in the reactor is monitored by a pressure gauge connected to it, and the pressure in the reactor remains above 5.0 MPa during the reaction.
[0045] (3) Extraction of decomposition products of the resin matrix: After the near-critical water treatment, turn off the power, take out the reaction kettle and cool it to room temperature with tap water to transfer the reaction products, the aqueous decomposition liquid and solid phase products obtained, and then extract with ethyl acetate The aqueous phase decomposition liquid is mainly phenol and phenol derivatives (such as figure 2 As shown), the fiber fabric in the solid phase product obtained at the same time has obvious delamination, and the copper foil is easy to peel off (such as image 3 Shown).
[0046] (4) Recovery of copper foil and glass fiber cloth: the solid phase product (glass fiber cloth and copper foil) obtained in step (3) is soaked in acetone for 24 hours, then washed with distilled water 5 times, and placed in a temperature of 100 ℃ Dry in an oven for 3 hours, and finally obtain the separation product of copper foil and glass fiber cloth (such as Figure 4-6 Shown).
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the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
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