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Method for extracting metallic silver from waste circuit board

A technology for extracting metal from waste circuit boards, which is applied to the improvement of process efficiency, photography technology, instruments, etc., can solve the problems of restrictions, secondary pollution, difficult recycling of leachate, etc., and achieve the effect of strong selective leaching and avoiding discharge

Inactive Publication Date: 2015-10-21
CHINA NAT ELECTRIC APP RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the need to use strong corrosive chemical reagents, this method is easy to cause secondary pollution
The selective leaching method mainly utilizes the reaction of precious metals such as gold and silver with some complexing agents (such as cyanide) to generate water-soluble metal complex ions to realize the separation of precious metals from common metals, but the toxicity of cyanide limits the application of this method. use, and the leachate is difficult to recycle, which is likely to cause secondary pollution

Method used

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  • Method for extracting metallic silver from waste circuit board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Using waste computer printed circuit boards as raw materials, it contains 0.32% Ag and 17.9% Cu.

[0019] Crush 50g of the above-mentioned raw materials into 1-2mm fragments, add them into a mechanically stirred reactor, add 0.3 L of disodium edetate solution with a concentration of 15g / L and 30ml of oxidant hydrogen peroxide at the same time, and stir and leach for 1h. After leaching, filter and separate the leaching solution and leaching slag, add copper flakes to the leaching solution to replace to obtain coarse silver powder, the replaced solution is added to the cationic diaphragm electrolytic cell as the catholyte, and the stainless steel is used as the cathode plate for electrolysis to obtain copper powder, and the electrolysis conditions adopt the conventional process conditions. After electrolysis, the waste electrolyte is returned to the leaching process for recycling. Among them, the leaching rate of silver is 90.5%, and the leaching rate of other metals suc...

Embodiment 2

[0021] Using waste mobile phone printed circuit boards as raw materials, it contains 0.53% Ag and 23.5% Cu.

[0022] Crush 50g of the above-mentioned raw materials into 1-2mm fragments, add them into a mechanically stirred reactor, add 0.5 L of ethylenediamine solution with a concentration of 20g / L and 100ml of oxidant hydrogen peroxide, and stir and leach for 2 hours. After leaching, filter and separate the leaching solution and leaching slag, add copper flakes to the leaching solution to obtain coarse silver powder, add the replaced solution to the cationic membrane electrolytic cell as catholyte, and use stainless steel as the cathode plate for electrolysis to obtain copper powder, waste electrolyte after electrolysis Return to the leaching process for recycling. The leaching rate of silver is 93.7%, and the leaching rate of other metals such as copper is less than 5%. The resulting leaching slag is used to extract the remaining metal and non-metal materials.

Embodiment 3

[0024] The components after dismantling the printed circuit boards of waste mobile phones are used as raw materials, which contain 1.12% Ag and 41.7% Cu.

[0025] Crush 50g of the above-mentioned raw materials into 1-2mm fragments and add them to a mechanically stirred reactor. At the same time, add 0.5 L of ethylenediamine solution with a concentration of 20g / L and 150ml of oxidant sodium hypochlorite solution, and stir and leach for 3h. After leaching, filter and separate the leaching solution and leaching slag, add copper flakes to the leaching solution to obtain coarse silver powder, add the replaced solution to the cationic membrane electrolytic cell as catholyte, and use stainless steel as the cathode plate for electrolysis to obtain copper powder, waste electrolyte after electrolysis Return to the leaching process for recycling. The leaching rate of silver is 93.5%, and the leaching rate of other metals such as copper is less than 5%. The resulting leaching slag is use...

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Abstract

The invention discloses a method for extracting metallic silver from a waste circuit board. The method comprises the steps that after the waste circuit board is smashed into crushed materials, the crushed materials are placed into an extracting solution of a leaching reactor to be subjected to selective leaching reaction, wherein the extracting solution is formed by a complexing agent and an oxidizing agent; a copper sheet is added to an obtained leaching solution to be subjected to replacement reaction, and the metallic silver is prepared. The technology is simple, the cost is low, the metallic silver in the circuit board can be subjected to complexing leaching in a selective mode, it is avoided that strong acid is in use, and the environment-protected and resource-recovered processing on the metallic silver of the waste circuit board is achieved.

Description

technical field [0001] The invention relates to a method for extracting metallic silver from waste circuit boards, and belongs to the technical fields of metal recovery and solid waste recycling. Background technique [0002] The disposal of e-waste has become an urgent problem in the world. Printed circuit boards are an important part of electronic products, accounting for a considerable proportion, so the treatment of printed circuit boards is the key to the disposal and utilization of electronic waste. Waste printed circuit boards are different from general solid waste. It contains many heavy metals and toxic and harmful substances such as lead, cadmium, mercury, hexavalent chromium, polyvinyl chloride and halogenated flame retardants. Improper disposal will inevitably have a serious impact on the environment; at the same time, waste printed circuit boards contain gold, silver, palladium, platinum and other precious metals, which have high economic value. According to s...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B11/00C25C1/12
CPCY02P10/20
Inventor 王鹏程张承龙拓磊赵颖璠郑飞龙白建峰王景伟韩文生刘阳赵新符永高万超胡嘉琦曹诺邓梅玲
Owner CHINA NAT ELECTRIC APP RES INST
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