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A method for recovering solder from waste circuit boards

A technology of waste circuit boards and soldering tin, applied in the direction of improving process efficiency, etc., can solve the problems of exhaust gas, high cost, affecting solder recovery rate, etc., achieve the effect of being friendly to the environment and improving recovery rate

Active Publication Date: 2018-08-03
珠海格力绿色再生资源有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it can only handle single-sided boards, and requires that the circuit board must have an exposed solder surface, which affects its application on double-sided boards; and when the temperature of melting solder is high, it will emit toxic and harmful exhaust gases; there is still a small amount of solder that inevitably sticks Attached to the light board, affecting the recovery rate of solder
[0004] The patent application with the application number 201310657568.6 discloses an environmentally friendly detinning liquid used on waste circuit boards. The liquid is used to soak the waste circuit boards, and nitric acid is used to dissolve the solder and remove the components on the circuit boards. However, this method There is a problem that the formula of the detinning solution is complex and the cost is high; the recovered solder is tin hydroxide, which needs further treatment; detinning of the solution produces a large amount of waste water, which needs to be treated

Method used

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  • A method for recovering solder from waste circuit boards

Examples

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Effect test

Embodiment 1

[0046] Used to illustrate the method of the present invention for reclaiming solder from waste circuit boards

[0047] Put the waste circuit boards obtained above in a Y800 hot air drum, rotate the drum at a speed of 20 rpm, and at the same time pass hot air at a temperature of 185°C, and obtain a mixture after heat treatment for 30 minutes; put the mixture in S49 vibration classification In the sieve, the mixture is sequentially passed through vibrating grading sieves with different aperture sizes to separate the bare board (with solder particles remaining on the surface), components and solder particles.

[0048] The bare board is crushed once to a particle size of about 20 mm, and then further crushed to a particle size of less than 0.5 mm, and the crushed particles are added to an eddy current electrostatic separation device to obtain metal powder and non-metal powder. The solder particles and metal powder are mixed to obtain mixed metal powder.

[0049] The sodium hydrox...

Embodiment 2

[0051] The method for reclaiming solder from waste circuit boards: with reference to the method in Example 1, the difference is that during the electrolytic reaction, the cell voltage is 3.5 volts, and the current density is 250 amps / square meter;

[0052] After detection and conversion, the purity of the obtained sponge tin product is 98.4%, and the yield is 98.9%.

Embodiment 3

[0054] The method for reclaiming solder from waste circuit boards: with reference to the method in Example 1, the difference is that in the electrolytic reaction process, the cell voltage is 2.5 volts, and the current density is 150 amps / square meter;

[0055] After detection and conversion, the purity of the obtained sponge tin product is 99.3%, and the yield is 93.4%.

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Abstract

The invention discloses a method for recycling soldering tin from a waste circuit board. The method comprises the following steps that firstly, metal mixed powder containing soldering tin particles is separated from the waste circuit board; and secondly, under the electrolysis condition, the metal mixed powder is added in an electrolysis system with an alkaline solution as an electrolyte, and metallic tin is obtained through the electrolysis reaction. According to the method, the metal mixed powder containing the soldering tin particles is separated from the waste circuit board, the soldering tin can be comprehensively recycled, and the tin recycling rate is increased; the characteristic that the metallic tin can be reacted with the alkaline solution to form tin ions is utilized, the metal mixed powder is added in the electrolysis system with the alkaline solution as the electrolyte, the metallic tin and other metal (such as copper and silver) are separated through the electrolysis reaction, accordingly, sponge tin is obtained, the sponge tin product is high in purity, and a tin ingot can be obtained through direct ingot casting.

Description

technical field [0001] The invention relates to the field of metal tin recovery, in particular to a method for recovering solder from waste circuit boards. Background technique [0002] With the increasing number of domestic waste electronic appliances year by year, electronic waste has become an important issue related to environmental protection and circular economy, and waste circuit boards are the most complicated and difficult parts of electronic waste. In the past, the focus was often on the recovery of precious metals and copper, but in fact circuit boards still contain an average of about 2wt% solder, and the recovery value is also very high, and the detachment of solder also helps the recovery of copper and precious metals. [0003] Patent application No. 201410160701.1 discloses a method and device for separating solder on waste circuit boards. In this method, the solder surface of waste circuit boards is immersed in molten salt to melt and separate the solder. Ho...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25C5/02C22B7/00
CPCC22B7/008C25C5/02Y02P10/20
Inventor 王九飙王红霞王琳曹全红周文斌
Owner 珠海格力绿色再生资源有限公司