CN105385860A - Method for extracting copper from waste circuit boards - Google Patents

Abstract

The invention discloses a method for extracting copper from waste circuit boards. The method comprises the steps that the waste circuit boards are crushed and then placed into a waste etching solution to be stirred for 20-60 min, and the process for extracting the copper from the waste circuit boards is finished. Tests prove that by the adoption of the method, the copper on the waste circuit boards is extracted; the amount of generated waste liquid is reduced by using the waste etching solution; the operation process is simple and feasible, the cost is low, and the method has great significance for environment protection.

Description

A method for leaching copper from waste circuit boards

technical field

The invention belongs to the technical field of electronic waste recycling and waste liquid reuse, and relates to a method for leaching copper from waste circuit boards.

Background technique

With the production and scrapping of electronic and electrical products, the amount of discarded circuit boards is increasing day by day. In the leaching process of waste circuit boards, the recovery of copper by hydrometallurgy generally adopts methods such as crushing and using inorganic acids or organic solvents. During the leaching process, a large amount of waste liquid will be generated, which not only wastes a lot of resources, but is also economical. The cost is high, and it also causes secondary pollution to the environment. Therefore, finding a method to replace copper leaching with inorganic acid or organic solvent has become an urgent problem in the recycling process of waste circuit boards.

There are as many as 20 processes in the production process of printed circuit boards (PCBs), among which copper etching is the process that produces a large amount of waste liquid in PCB enterprises. Calculated by consuming at least 1.5 ^m3 of etching liquid per 1000 square meters of circuit boards produced, the global annual Consumption of 300 million cubic meters of etching solution is still increasing at a rate of 15%-18%. When the copper-etching ability of the etching solution decreases, it becomes a waste etching solution, and the concentration of heavy metals in it is as high as 80-120g/l (mainly copper). At present, the copper chloride etching solution is widely used, and the test shows that copper chloride The waste etching solution still has the ability to continue to dissolve copper, so the waste etching solution can be used as a copper-dissolving leaching agent to continue to extract copper from waste circuit boards, so as to achieve the purpose of treating waste with waste.

At present, the domestic research work on the wet copper extraction of waste circuit boards has made important progress, and there are a number of patents on the recycling technology of waste circuit boards.

Circuit board recycling technology patent:

Patent [200910009562.1] crushes waste circuit boards, and then extracts copper by adding nitric acid to copper residues to regenerate valuable metal resources; patent [201310292820.8] crushes waste circuit boards to 40-200 meshes, dissolves sticky After high-voltage electrostatic separation, sulfuric acid and aqua regia are used to extract precious metals; patent [201110092620.9] adopts methods such as crushing, electrostatic separation, calcination, and sulfuric acid extraction to realize the recycling of valuable metal resources.

All the technologies adopted in the above patents require the use of new leaching reagents in the treatment of copper recovery, thereby generating new waste liquids, such as acidic waste liquids or organic waste liquids, which will cause additional impact on the environment and Secondary pollution is not conducive to the sustainable development of waste circuit board recycling.

Contents of the invention

The purpose of the present invention is to provide a method for leaching copper from waste circuit boards.

The method comprises the steps of:

After the waste circuit board is pulverized, it is placed in the waste etching solution and stirred for 20-60 minutes to complete the process of leaching copper from the waste circuit board.

In the crushing step of the above method, the particle size of the crushed circuit board is 0.1-8 mm, specifically 4 mm.

The waste etching solution is copper chloride waste etching solution, specifically acidic copper chloride waste etching solution or alkaline copper chloride waste etching solution.

The solid-liquid ratio of the waste circuit board to the waste etching solution is 1g:2-36mL.

In the stirring step, the stirring speed is 100-1000r/min, specifically 500-700r/min;

The temperature is normal temperature;

The time is 32-40min.

The waste circuit board is a single-layer or multi-layer circuit board without components.

Experiments have proved that using the method provided by the invention to extract copper from waste circuit boards can realize reuse of waste etching solution, reduce the amount of waste liquid, the operation process is simple and feasible, and the cost is low, which is of great significance to environmental protection.

detailed description

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The methods are conventional methods unless otherwise specified. The raw materials can be obtained from open commercial channels unless otherwise specified.

In the following examples, the waste etching solution used comes from Kunshan Qiandeng Sanwaste Purification Co., Ltd., which is produced by a circuit board manufacturer after etching copper. The specific components are shown in Table 1.

The concrete composition of table 1, waste etching solution (solvent is water)

Embodiment 1, leaching copper from multilayer waste circuit board

At room temperature, the computer multi-layer waste circuit board was selected as the test material, crushed to a particle size of 4mm, soaked in waste etching solution, the solid-liquid ratio (g/ml) was 1:36, and the stirring speed was 500r/min. The soaking time was 32 minutes.

The test result shows that the copper content in the remaining residue powder is less than 5%, and the copper in the double-layer waste circuit board is leached.

Embodiment 2, leaching copper from single-layer waste circuit board

At room temperature, select the single-layer waste circuit board of the cathode ray tube display as the test material, crush it to a particle size of 8mm, soak it in the waste etching solution, the solid-liquid ratio (g/ml) is 1:2, and the stirring speed is 700r /min, soaking time is 40 minutes.

The test result shows that the copper content in the remaining residue powder is less than 5%, and the copper in the single-layer waste circuit board is leached.

Embodiment 3, various extractants compare the extraction efficiency of copper from computer waste circuit boards

Table 1. Comparison of extraction efficiency of copper from circuit boards by various extraction agents

Note: The crushed particle size is <2mm, the solid-to-liquid ratio (g/ml) is 1:36, and the stirring speed is 700r/min.

From the comparison in Table 1, it can be seen that under the same crushing particle size, solid-to-liquid ratio, and stirring speed, using the waste etching solution to extract copper from the circuit board requires a lower extraction temperature, a shorter extraction time, and a lower copper extraction rate. high without generating additional waste.

Claims (8)

1. A method for extracting copper from waste circuit boards, comprising the steps of: after waste circuit boards are pulverized, placed in waste etching solution and stirred for 20-60min, completing the process of extracting copper from waste circuit boards . 2. The method according to claim 1, characterized in that: in the crushing step, the particle size of the crushed circuit board is 0.1-8 mm, specifically 4 mm. 3. The method according to claim 1 or 2, characterized in that: the waste etching solution is copper chloride waste etching solution, specifically acid copper chloride waste etching solution or alkaline copper chloride waste etching solution. 4. The method according to any one of claims 1-3, characterized in that: the solid-to-liquid ratio of the waste circuit board to the waste etching solution is 1 g: 2-36 mL. 5. The method according to any one of claims 1-4, characterized in that: in the stirring step, the stirring speed is 100-1000r/min, specifically 500-700r/min. 6. The method according to any one of claims 1-5, characterized in that: in the stirring step, the stirring temperature is normal temperature. 7. The method according to any one of claims 1-6, characterized in that: in the stirring step, the stirring time is 32-40min. 8. The method according to any one of claims 1-7, wherein the waste circuit board is a single-layer or multi-layer circuit board without components.