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A method for selectively stripping metal gold from the surface of waste printed circuit boards

A technology for printed circuit boards and waste circuit boards, applied in the direction of improving process efficiency, etc., can solve problems such as restrictions, difficult recycling of leachate, secondary pollution, etc., to avoid waste liquid discharge, low cost, and realize closed-circuit circulation Effect

Active Publication Date: 2017-09-19
SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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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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  • A method for selectively stripping metal gold from the surface of waste printed circuit boards

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Using waste mobile phone circuit boards as raw materials, it contains 0.13wt% Au and 20.9wt% Cu.

[0028] Extraction process such as figure 1 Shown: Add 182g of mobile phone circuit boards after pretreatment to remove components into the reaction container, and at the same time add 1000ml of prepared gold removal solution, in which the mass fraction of methanesulfonic acid is 29.6%, and the mass fraction of hydrogen peroxide is 7.2%. Set to leaching for 3-4 hours. Stir the solution after leaching, then take out the mobile phone circuit board, wash it, collect it, and use it to extract other metals and non-metallic materials; filter the degold solution to obtain the copper-nickel solution and the peeled off gold foil, and the copper-nickel solution Copper powder or copper sheet is obtained by electrodeposition, and the electrodeposition process is 100-300A / M 2 , the plate is made of stainless steel plate, the liquid contains 1g / L copper after electrolysis, the direct r...

Embodiment 2

[0030] Using computer memory stick as raw material, Au 0.05wt%, Cu 21.1wt%.

[0031] Extraction process such as figure 1 Shown: Add 150g of the computer memory stick after the pretreatment to remove the components into the reaction container, and at the same time add 1000ml of the prepared gold removal solution, in which the mass fraction of methanesulfonic acid is 22.2%, and the mass fraction of hydrogen peroxide is 8.0%. Set to leaching for 3-4 hours. Stir the solution after leaching, then take out the mobile phone circuit board, wash it, collect it, and use it to extract other metals and non-metallic materials; filter the degold solution to obtain a copper-containing solution and peeled off gold foil, pass the copper-nickel solution through Copper powder or copper sheet is obtained by electrodeposition, and the electrodeposition process is 100-300A / M 2 , the plate is made of stainless steel plate, the liquid contains 1g / L copper after electrolysis, the direct recovery rat...

Embodiment 3

[0033] Using waste mobile phone circuit boards as raw materials, it contains 0.13% Au and 20.9% Cu.

[0034] Extraction process such as figure 1 Shown: Add 103g of mobile phone circuit boards after pretreatment to remove components into the reaction container, and at the same time add 1000ml of prepared gold removal solution, in which the mass fraction of sulfamic acid is 13.2%, and the mass fraction of hydrogen peroxide is 10.68%. Leach for 3-4 hours. Stir the solution after leaching, then take out the mobile phone circuit board, wash it, collect it, and use it to extract other metals and non-metallic materials; filter the degold solution to obtain the copper-nickel solution and the peeled off gold foil, and the copper-nickel solution Copper powder or copper sheet is obtained by electrodeposition, and the electrodeposition process is 100-300A / M 2 , the plate is made of stainless steel plate, the liquid contains 1g / L copper after electrolysis, the direct recovery rate of cop...

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Abstract

The invention discloses a method for selectively peeling away metal gold from the surface of a waste printed circuit board. The method comprises the steps that the waste circuit board is used as a raw material, components are removed through preprocessing at first, and cleaning and drying are performed; then, a degolding solution is added for a leaching reaction on the basis that the solid-liquid massic volume ratio is 1:5-1:10, and the leaching reaction time is 2-4 h; the degolding solution comprises, by mass, 10.1-47.0% of a sulfoacid solute, 3.5-11.2% of an oxidizing agent and the balance water; after leaching is finished, a solution is filtered to obtain a solution containing copper and nickel and filter residues containing gold foil, and the filtrate is molten to obtain gold ingots; the leached solution containing copper and nickel is circularly used for leaching the waste printed circuit board after copper is recycled through electro-deposition, and nickel is extracted from the circularly-used solution; a mother solution is circularly used for leaching the waste printed circuit board. The method is simple in technology, low in cost and capable of achieving green resource processing of metal gold in the waste printed circuit board.

Description

technical field [0001] The invention relates to a method for selectively stripping metal gold from the surface of waste printed circuit boards, and belongs to the technical field of metal recycling and solid waste recycling. Background technique [0002] In recent years, the printed circuit board manufacturing industry in mainland China has developed rapidly at an average annual growth rate of 14.4%. By 1995, the total output of printed circuit boards in my country ranked fifth in the world, and its output value accounted for 5.2% of the world's total output value of printed circuit boards. In 2000, the demand for printed circuit boards in the domestic electronics industry soared to 150,000 tons. In my country, where the total size of the electronic product market has reached 1 trillion yuan and the output value of the electronic industry ranks fourth in the world, the number of discarded printed circuit boards is very large. Take Dongguan, Guangdong, where the electronics ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B11/00
CPCY02P10/20
Inventor 张承龙郑飞龙赵颖璠白建峰王景伟王鹏程
Owner SHANGHAI SECOND POLYTECHNIC UNIVERSITY