WO2021077922A1

WO2021077922A1 - Method for extracting copper from waste printed circuit board using glycine solution

Info

Publication number: WO2021077922A1
Application number: PCT/CN2020/113868
Authority: WO
Inventors: 陈梦君; 韩昀晖; 舒建成; 王蓉; 符俊灵; 易小霞
Original assignee: 西南科技大学
Priority date: 2019-10-21
Filing date: 2020-09-08
Publication date: 2021-04-29
Also published as: CN110629037A

Abstract

Provided is a method for extracting copper from a waste printed circuit board using glycine. The steps are: through dismantling and mechanical crushing treatment to obtain the sample of the waste printed circuit board with the smaller particle size; under the stirring condition, placing the above pretreated sample in the mixed leaching agent of glycine and hydrogen peroxide, after leaching at the constant temperature for a period of time, the leaching solution is filtered to extract copper. Compared with traditional leaching agents, it is environmentally friendly and highly efficient, the leaching rate of copper can reach up to 94%, which is an environmentally friendly treatment method.

Description

Method for extracting copper from waste printed circuit boards using glycine solution

Technical field

The invention relates to a method for recycling waste printed circuit board resources, in particular to a method for extracting copper from waste printed circuit boards by using glycine.

Background technique

In recent years, with the rapid development of electronic technology and electronic information industry, various electronic products have emerged one after another. Various electronic devices such as mobile phones, computers, and home appliances have become more and more popular. The service life of electronic products has become shorter and shorter, and the replacement of electronic products has accelerated , Resulting in a sharp increase in the amount of electronic waste. As one of the most important components in electronic equipment, the number of printed circuit boards also increases with the increase in the amount of electronic waste. Waste printed circuit boards contain a lot of metal resources, including basic metals (Al, Cu, Fe, Ni, Pb, Sn, Zn, etc.), precious metals and rare metals (Au, Ag, Pd, Rh, Se, etc.), and toxic heavy metals (As, Pb, Cd, etc.), the copper content is the highest. If the waste printed circuit boards can be effectively recycled, not only the ecological environment can be achieved, but also a large amount of copper resources can be obtained through recycling.

The recycling and processing of waste printed circuit boards first started in 1969 by the U.S. Bureau of Mines. After more than one hundred years of exploration and research, there is a solid theoretical foundation for WPCBs recycling technology at home and abroad, and many mature processing technologies have been explored. At present, the most used treatment technologies are physical mechanical treatment, pyrometallurgy, hydrometallurgy, microbiological method and supercritical fluid method. Among them, the pyrometallurgical and physical mechanical treatment methods have high equipment costs, high energy consumption, and serious pollution, and the microbiological method and supercritical fluid method are not mature yet, have small processing capacity, and are not widely used. Hydrometallurgical technology is the most widely used in many waste printed circuit board processing technologies. It has attracted the attention of various researchers because of its simple operation and low energy consumption. Patent CN107574310A discloses a method for efficiently leaching copper from waste circuit boards. The waste circuit board polymetal powder is slurried with a sulfuric acid solution, and manganese oxide ore is added as an oxidant for leaching. The leaching rate of copper reaches more than 96%, but this method is selected As a leaching agent, sulfuric acid solution has a certain degree of danger. Improper operation can easily cause harm to the human body, and the acidic waste liquid produced by leaching needs additional treatment.

Summary of the invention

In order to solve the above problems, the present invention provides a method for extracting copper from waste printed circuit boards by using glycine. This method is based on hydrometallurgical technology, and the selected leaching agent is environmentally safe and has the characteristics of safe operation, simple process, and no acid and alkali waste liquid generated during the leaching process.

In order to achieve the above-mentioned objective, the technical solution adopted by the present invention is as follows:

A method for leaching copper from waste printed circuit boards using glycine, replacing traditional inorganic acid with glycine as the leaching agent, and hydrogen peroxide as the oxidant, leaching copper from waste printed circuit boards under constant temperature stirring conditions, specifically including the following steps :

Step 1: Disassemble, cut, and crush the waste printed circuit boards to obtain pre-processed samples;

Step 2: Under stirring conditions, put the above pretreated sample in a mixed leaching agent of glycine and hydrogen peroxide, after leaching at a constant temperature for a period of time, the leaching solution is filtered to extract copper.

Further, the waste printed circuit board is disassembled, sheared, and crushed to obtain a pretreated sample with a particle size of ≤ 1 mm.

Further, in the mixed leaching agent of glycine and hydrogen peroxide, the concentration of glycine is 0.25-1.25 mol/L, and the volume fraction of hydrogen peroxide is 2.5%-10%.

Further, the ratio of the pretreated sample to the mixed leaching agent is 5-25 g/L.

Further, the constant temperature is from room temperature to 60°C, and the leaching time is more than 480 minutes.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention uses glycine instead of traditional inorganic acid to leaching copper from waste printed circuit boards. Hydrogen peroxide is selected as the oxidant, no strong acid or strong alkali reagents are added, the operation process is safe, the energy consumption is low, and the copper leaching efficiency is high. , Can reach more than 94%.

(2) The present invention is environmentally friendly, no toxic and harmful by-products are produced during the leaching process, and no acid/alkali waste liquid is generated after leaching. The resulting copper glycinate is harmless to the environment and is convenient for subsequent processing; glycine and other organic acids It's easier to get than cheap.

Description of the drawings

Figure 1 is a process flow diagram of the method for leaching copper from waste printed circuit boards with a glycine solution according to the present invention.

Detailed ways

In order to better illustrate the present invention, specific examples are given below to describe the present invention in more detail, and the protection scope of the present invention is not limited to the examples given.

With reference to Fig. 1, the method for extracting copper from waste printed circuit boards by using glycine in the present invention includes the following steps:

Step 1: Disassemble, cut, shatter, and other methods of waste printed circuit boards to obtain pre-processed samples;

Step 2: Prepare a certain concentration of glycine solution;

Step 3: Add a certain amount of hydrogen peroxide to the glycine solution, mix it evenly to obtain a mixed solution of glycine and hydrogen peroxide, and use the mixed solution as the leaching agent;

Step 4: Under magnetic stirring, at a constant temperature, add a certain amount of the waste printed circuit board sample pretreated in step 1, and after leaching for a period of time, the copper in the circuit board is immersed in the solution, and the mixture is filtered.

Example 1

First, the waste printed circuit boards are manually disassembled, and then crushed to a particle size of ≤1mm with a double-shaft shearing machine and a crusher. Then prepare a glycine solution in a 500mL beaker, stir with a glass rod, add hydrogen peroxide, dilute the ultrapure water to 200mL, stir evenly with a magnetic stirrer, and finally obtain a concentration of 1mol/L glycine and a volume fraction of 2.5%. A mixed solution of hydrogen oxide, using the mixed solution as a leaching agent. Add the crushed waste printed circuit board powder, the ratio of the powder to the leaching agent is 5g/L, the temperature is controlled at 30℃, and the magnetic stirrer is used for continuous stirring and leaching for 480 minutes. The resulting mixture is diluted by centrifugal filtration to measure the copper content. The calculated copper leaching rate is 78.65%.

Example 2

Other conditions are the same as in Example 1. Experiments were carried out at different temperatures. The specific results are as follows:

Table 1 Experiments at different temperatures

It can be seen from Table 1 that at room temperature to 40°C, the leaching effect of copper is better, and at 30°C, the leaching effect of copper is the best, and the preferred temperature is 30°C.

Example 3

Other conditions are the same as in Example 1. The experiment was carried out by mixing hydrogen peroxide with different volume fractions in the leaching agent. The specific results are as follows:

Table 2 Experiments with different hydrogen peroxide concentrations

It can be seen from Table 2 that when the volume fraction of hydrogen peroxide in the leaching agent is 5.0-10%, the leaching effect of copper is better, and when the volume fraction of hydrogen peroxide in the leaching agent is 10%, the leaching effect of copper is the best, and peroxide is preferred. The hydrogen volume fraction is 10%.

Example 4

Other conditions are the same as in Example 1. Experiments were carried out under different ratios of powder and leaching agent. The specific results are as follows:

Table 3 Experiments on the ratio of different powders and leaching agents

It can be seen from Table 4 that when the ratio of powder to leaching agent is 5-15g/L, the leaching effect of copper is better, and when the ratio of powder to leaching agent is 10g/L, the leaching effect of copper is the best. Powder and leaching agent are preferred. The ratio is 10g/L.

Example 5

Other conditions are the same as in Example 1. Experiments were carried out under different glycine concentrations. The specific results are as follows:

Table 4 Experiments with different glycine concentrations

It can be seen from Table 5 that under the condition of excessive glycine, the copper leaching rate has little effect. When the glycine acid concentration is 0.25 to 1.25 mol/L, the copper leaching rate can basically reach more than 88%. However, when the concentration of glycine is 1mol/L, the leaching effect of copper is the best. Preferably, the concentration of glycine is 1mol/L.

The above are the preferred embodiments of the present invention, but do not represent the limitation of the protection scope of the present invention. Those skilled in the art make some non-essential improvements to the present invention based on the above-mentioned content of the invention, which still belong to the protection scope of the present invention.

Claims

A method for extracting copper from waste printed circuit boards using glycine is characterized in that it specifically includes the following steps:

Step 1: Disassemble, cut, and crush the waste printed circuit boards to obtain pre-processed samples;

Step 2: Under stirring conditions, put the above pretreated sample in a mixed leaching agent of glycine and hydrogen peroxide, and leaching for a period of time at a constant temperature.
The method according to claim 1, wherein the waste printed circuit board is disassembled, sheared, and broken to obtain a pretreated sample with a particle size of ≤ 1 mm.
The method according to claim 1, wherein the concentration of glycine in the mixed leaching agent of glycine and hydrogen peroxide is 0.25-1.25 mol/L.
The method of claim 1, wherein the volume fraction of hydrogen peroxide is 2.5%-10%.
The method according to claim 1 or 3, wherein the ratio of the pretreated sample to the mixed leaching agent is 5-25 g/L.
The method of claim 1, wherein the constant temperature is from room temperature to 60°C, and the leaching time is more than 480 minutes.