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Method for recovering precious metal from waste circuit boards

A technology of waste circuit boards and precious metals, applied in the field of waste resource utilization, can solve the problems of lead vapor environment and human injury, and achieve the effects of low cost, short process and shortened process flow

Inactive Publication Date: 2016-01-27
建昇电子科技(惠州)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Only because lead-containing substances are used as the precious metal collector at high temperature, the lead vapor produced will cause great harm to the environment and the human body

Method used

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  • Method for recovering precious metal from waste circuit boards

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Circuit board pretreatment. The waste circuit boards are subjected to coarse crushing and fine crushing, then electrostatic separation, and the obtained metal enrichment is subjected to hydraulic separation, and the obtained precious metal enrichment is hot-pressed and electrolytically refined to obtain precious metal anode slime, and then the precious metal anode slime Roasting;

[0023] (2) Silver recovery. The roasted precious metal anode slime is dissolved in 10% nitric acid solution with a mass fraction of 10% according to the solid-to-liquid ratio of 1:4 and dissolved at a temperature of 60°C for 3 hours. After filtering, the solution is added to the solution to precipitate silver ions. The molar ratio is 2.2:1, the temperature of the precipitated silver is 55°C, and the time is 3 hours. The filtered silver chloride is dissolved with 18% ammonia water, the dissolution temperature is 55°C, and the time is 2 hours. The obtained solution is added with hydrazine ...

Embodiment 2

[0029] (1) Circuit board pretreatment. The waste circuit boards are subjected to coarse crushing and fine crushing, then electrostatic separation, and the obtained metal enrichment is subjected to hydraulic separation, and the obtained precious metal enrichment is hot-pressed and electrolytically refined to obtain precious metal anode slime, and then the precious metal anode slime Roasting;

[0030] (2) Silver recovery. The roasted noble metal anode slime is dissolved in 12% nitric acid solution with a mass fraction of 12% according to the solid-to-liquid ratio of 1:4 and dissolved at a temperature of 55°C for 4 hours. After filtering, potassium chloride is added to the solution to precipitate silver ions. The molar ratio is 3:1, the temperature of the precipitated silver is 55°C, and the time is 3 hours. The filtered silver chloride is dissolved with 15% ammonia water, the dissolution temperature is 55°C, and the time is 2.5 hours. The obtained solution is added with zinc po...

Embodiment 3

[0036] (1) Circuit board pretreatment. The waste circuit boards are subjected to coarse crushing and fine crushing, then electrostatic separation, and the obtained metal enrichment is subjected to hydraulic separation, and the obtained precious metal enrichment is hot-pressed and electrolytically refined to obtain precious metal anode slime, and then the precious metal anode slime Roasting;

[0037] (2) Silver recovery. Dissolve the calcined precious metal anode slime in a solid-to-liquid ratio of 1:2.5 by adding a 7.5% nitric acid solution at a temperature of 60°C for 3 hours. After filtering, add calcium chloride to the solution to precipitate silver ions. The molar ratio is 2.5:1, the temperature of the precipitated silver is 65°C, and the time is 3 hours. The filtered silver chloride is dissolved with 17% ammonia water, the dissolution temperature is 50°C, and the time is 3 hours. The obtained solution is added with hydroxylamine hydrochloride The reducing agent is reduc...

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Abstract

The invention provides a method for recovering precious metal from waste circuit boards and belongs to the field of waste resource utilization. The method comprises the following steps that (1) the circuit boards are pretreated, (2) silver is recovered, (3) chloridizing leaching is carried out, (4) gold is reduced through nitrite, and (5) palladium is reduced through hydrazine hydrate. Compared with the prior art, the method is advantageous in that the recovery cost is lower, the process is short, environmental friendliness is achieved, and the recovery rate of the precious metal is high.

Description

technical field [0001] The invention provides a method for recycling precious metals from waste circuit boards, which belongs to the field of resource utilization of waste. Background technique [0002] my country has become the world's largest producer of electronic products and e-waste. The disposal of electronic waste is an urgent problem to be solved in our country. Printed circuit board (PCB for short) is an important part of electronic products. Its composition includes organic substrates and electronic components containing high-grade metals assembled on the substrates. The main metal components are: Cu, Fe, Sn , Ni, Pb, Zn, Sb, Au, Ag, Pd, etc., its recovery value is much higher than that of general municipal waste, and it is an important "urban mine". If discarded circuit boards cannot be effectively disposed of, it will not only be a great waste of resources, but the heavy metals in them will also pollute the environment. [0003] Seeking economical, effective a...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B11/00
CPCY02P10/20
Inventor 董亚伦
Owner 建昇电子科技(惠州)有限公司
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