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Recycling method of waste printed circuit board

A technology for printed circuit boards and wastewater, applied in chemical instruments and methods, improvement of process efficiency, instruments, etc., can solve the problems of secondary pollution, high cost, no industrial feasibility, etc. The effect of reducing iron content and realizing waste recycling

Inactive Publication Date: 2017-07-14
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the existing chemical leaching of waste printed circuit boards, the leaching agents used include concentrated sulfuric acid, nitric acid, FeCl 3 etc. Although these leaching agents can bring a large degree of leaching, due to the high cost of the leaching agent itself and the secondary pollution problem, this form of leaching of waste printed circuit boards does not have practical industrial feasibility. sex
Flávia P.C. Silvas et al. (Printed circuit board recycling: Physical processing and copper extraction by selective leaching, Waste Management 46 (2015) 503-510) used sulfuric acid and hydrogen peroxide as leaching agents to carry out two-step leaching respectively. The first stage of sulfuric acid leaching , 90% Al, 8.6Sn, 40% Zn leaching, other metals are not leaching, the second stage hydrogen peroxide oxidative leaching, 10% Al, 100% Cu, 60% Zn leaching, other metals are not leaching, although the stage leaching method Significantly improve the efficiency of metal leaching and shorten the leaching time, but due to the large amount of chemical agents added, the cost is high, and a large amount of waste water is generated at the same time, causing new environmental pollution

Method used

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  • Recycling method of waste printed circuit board
  • Recycling method of waste printed circuit board
  • Recycling method of waste printed circuit board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] ① Pretreatment of waste printed circuit boards: disassemble the electronic components in the waste printed circuit boards by hand and crush them with a FW-400A high-speed universal grinder, pass through a 10-mesh standard sieve, and continue to crush the fragments that cannot pass the sieve until all After sieving, the collected powder was dried in an oven at 105°C for 24 hours, and the dried sample was used for leaching experiments.

[0025] The main metal content of the dried waste printed board powder was digested on the electric heating plate, and the results are shown in Table 1 below:

[0026] Table 1 Metal content in waste printed circuit board powder

[0027]

[0028]

[0029] ② Domestication of acidophilic Thiobacillus ferrooxidans: The acidophilic Thiobacillus ferrooxidans was domesticated successively to resistance to chloride ion, acid washing wastewater and WPCBs. First, carry out chloride ion tolerance acclimatization, set Cl - Concentration is 0g / ...

Embodiment 2

[0037] Steps ①②⑤ are the same as in Example 1 for the pretreatment of waste printed circuit boards, the domestication of Thiobacillus acidophilus ferrooxidans, and the recovery of metals.

[0038] ③Chemical leaching of waste printed circuit boards: Chemical leaching of waste printed circuit boards: Add 12g of WPCBs to 200mL of pickling wastewater, heat and stir, adjust the speed to 500rpm, the temperature to 25°C, and the leaching time to 3d. After chemical leaching, samples were taken to measure the metal content in the leaching solution. The concentrations of metal copper, zinc and lead were 6.89g / L, 3.95g / L and 1.57g / L, respectively, to determine the leaching rate. The experimental results show that the leaching rates of the three metals with the highest content: copper, zinc and lead are 46%, 100% and 100%, respectively.

[0039] ④ Microbial leaching of waste printed circuit boards: Add 20 mL of acclimated and cultured strains to the leaching solution of chemical leaching,...

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Abstract

The invention discloses a recycling method of a waste printed circuit board. Chemical-biological joint leaching is used for lixiviating metal in the waste printed circuit board by using strong acidity and high ferroic of pickling waste water. The recycling method includes the steps of conducting chemical leaching by using the pickling waste water to lixiviate Pb, Zn, Al, Fe, Sn and the like metal completely till the leaching rate of Cu reaches to 30% and over, and adding domesticated acidithiobacillus ferrooxidans to conduct microbial leaching till the leaching rate of Cu reaches to 90% and over. By adoption of the recycling method, the waste printed circuit board and the pickling waste water can be utilized comprehensively, the principle of using waste to eliminate waste is fully carried out, maximal resource recycling and treatment of the two wastes are achieved, not only the heavy metal in the waste printed circuit board is leached completely, but also the effective treatment of the pickling waste water is achieved.

Description

technical field [0001] The invention relates to a method for recycling waste printed circuit boards, in particular to a comprehensive utilization method for leaching and recovering metals in waste printed circuit boards by using pickling wastewater and simultaneously treating waste from the pickling wastewater. Background technique [0002] Waste printed circuit boards (WPCBs) are mainly PCBs substrates produced during the PCBs manufacturing process, scraps and discarded electronic products. With the elimination of electronic products, PCBs are eliminated, and the amount of discarded PCBs shows a high-speed growth trend. Therefore, electronic pollution caused by discarded PCBs has become a serious environmental problem. WPCBs usually contain plastics, inert oxides and metals, of which the metal content accounts for about 28% (copper: 10-20%, lead: 1-5%, nickel: 1-3%). The grade of the metal in the circuit board is much higher than that of general mineral deposits (such as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C25C1/12C02F3/34
CPCC02F3/34C22B7/007C25C1/12Y02P10/20
Inventor 孙秀云王莉莉王连军李桥李健生沈锦优韩卫清刘晓东张景雨晏鑫
Owner NANJING UNIV OF SCI & TECH
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