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Method for treating waste printed circuit board by using supercritical fluid

A printed circuit board, supercritical fluid technology, applied in cleaning methods and appliances, chemical instruments and methods, etc., can solve the problems that non-metallic materials cannot be recycled, the purity and recovery rate of metal recovery are low, and the required temperature and pressure are high.

Active Publication Date: 2021-10-22
DONGGUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the processing methods of waste printed circuit boards mainly include hydrometallurgy, mechanical physical method, pyrolysis method, and supercritical fluid method. Although the hydrometallurgical and mechanical physical methods are relatively mature in technology, they will cause serious damage to the environment during the processing process. Secondary pollution, and the recovery purity and recovery rate of metals are relatively low, and non-metallic materials cannot be recycled, so it will be gradually limited in practical applications; Circuit board, the organic resin in the circuit board is thermally decomposed into small molecule organic gas or liquid, and the glass fibers of the metal component and non-metal component in the pyrolysis solid product are automatically separated due to the destruction of the resin, which can realize metal and non-metal components. Effective separation of metal components without producing dioxin and other highly toxic gases, but this method often requires higher temperature, higher energy consumption and stricter conditions; the commonly used fluid in supercritical fluid method is water or water and Carbon dioxide, which requires high temperature and pressure and takes a long time to process, and its treatment effect is relatively general

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) Remove the electronic components on the waste printed circuit board, and then cut them into small pieces of 2cm×2cm;

[0034] (2) 2g small pieces are put into the supercritical reactor, add 50mL sodium chloride aqueous solution (the mass ratio of sodium chloride and water in the sodium chloride aqueous solution is 18:100, the quality of waste printed circuit board and sodium chloride aqueous solution The volume ratio is 2g:50mL), close the reactor, turn on the power supply and heat up, the reaction temperature is 300°C, the pressure is 15MPa, and the time is 1h. After the reaction is over, naturally cool to room temperature, open the supercritical reactor, and The phase and liquid phase are separated by filtration, and the liquid phase is heated to separate and precipitate dissolved substances, which are used to prepare chemical products. The solid phase is dried at 105° C. for 10 minutes to obtain a processed circuit board.

[0035]Its mass reduction rate ((initial...

Embodiment 2

[0037] (1) Remove the electronic components on the waste printed circuit board, and then cut them into small pieces of 2cm×2cm;

[0038] (2) 2g small pieces are put into the supercritical reactor, add 50mL sodium chloride aqueous solution (the mass ratio of sodium chloride and water in the sodium chloride aqueous solution is 27:100, the quality of waste printed circuit board and sodium chloride aqueous solution The volume ratio is 2g:50mL), close the reactor, turn on the power supply and heat up, the reaction temperature is 300°C, the pressure is 15MPa, and the time is 1h. After the reaction is over, naturally cool to room temperature, open the supercritical reactor, and The phase and the liquid phase are separated by filtration, and the liquid phase is heated to separate and precipitate dissolved substances, which are used to prepare chemical products. The solid phase is dried at 105° C. for 10 minutes to obtain a processed circuit board.

[0039] Its mass reduction rate ((in...

Embodiment 3

[0041] (1) Remove the electronic components on the waste printed circuit board, and then cut them into small pieces of 2cm×2cm;

[0042] (2) Put 2g small pieces into the supercritical reactor, add 50mL potassium chloride aqueous solution (the mass ratio of potassium chloride and water in the potassium chloride aqueous solution is 17.1:100, the quality of the waste printed circuit board and the potassium chloride aqueous solution The volume ratio is 2g:50mL), close the reactor, turn on the power supply and heat up, the reaction temperature is 300°C, the pressure is 15MPa, and the time is 1h. After the reaction is over, naturally cool to room temperature, open the supercritical reactor, and The phase and the liquid phase are separated by filtration, and the liquid phase is heated to separate and precipitate dissolved substances, which are used to prepare chemical products. The solid phase is dried at 105° C. for 10 minutes to obtain a processed circuit board.

[0043] Its mass r...

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PUM

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Abstract

The invention provides a method for treating a waste printed circuit board by using supercritical fluid, and belongs to the technical field of solid waste recovery. The method comprises the following steps that the waste printed circuit board is mixed with a metal chloride aqueous solution, and supercritical treatment is performed to obtain a treated circuit board. According to the method, the metal chloride aqueous solution is used as fluid to treat the waste printed circuit board in the supercritical environment, the metal chloride aqueous solution has good flowability, heat conductivity and solubility, organic components in the waste printed circuit board can be decomposed, a bonding layer of the circuit board can be separated, meanwhile, charged ions with strong polarity in the metal chloride can effectively attack covalent bonds of the bonding layer of the waste printed circuit board, the reaction temperature and pressure can be reduced, the reaction time can be shortened, and the treatment effect can be improved. The result shows that the mass reduction rate of the waste printed circuit board treated by the treatment method is 33.04%, and the thickness increase rate is 67.66%.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling, and in particular relates to a method for treating waste printed circuit boards with supercritical fluid. Background technique [0002] In recent years, with the rapid development of the electronics industry, the production and consumption capacity of electronic products has grown rapidly, and the replacement cycle of various products has gradually shortened. With the replacement of various electronic products, a large amount of electronic waste has been generated. As a basic component of electronic products, printed circuit boards (PCBs) are widely used in electronics-related fields, such as communications, home appliances, instrumentation, etc. It is estimated that the world's printed circuit board products are growing at an average annual rate of 8.7%, while my country's printed circuit board products are growing at an annual rate of 15%. The printed circuit board is a complex a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B08B7/00
CPCB08B7/0021
Inventor 郭晓娟金旭蔡均猛朱刚
Owner DONGGUAN UNIV OF TECH