Method for recycling copper, silver and gold step by step by using waste printed circuit board

A printed circuit board and copper recovery technology, applied in the field of copper, gold and silver recovery, can solve the problems of difficult to meet the requirements of resource utilization and market, complex nature, etc., and achieve short reaction time, simple operation and mild reaction conditions. Effect

Active Publication Date: 2022-07-08
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, due to the many types of metals and their complex properties, how to economically and efficiently separate and purify precious metals from various conventional metals is a key issue in the recycling of waste printed circuit boards, and it is also a difficult point in the treatment of waste printed circuit boards.
In addition, with the improvement of the manufacturing process of electronic products, the content of precious metals in printed circuit boards is gradually decreasing, while the content of conventional metals and non-metals is gradually increasing. The traditional recycling technology with precious metals as the main target is difficult to meet the requirements of resource utilization and market

Method used

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  • Method for recycling copper, silver and gold step by step by using waste printed circuit board
  • Method for recycling copper, silver and gold step by step by using waste printed circuit board
  • Method for recycling copper, silver and gold step by step by using waste printed circuit board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The relationship and scheme flow chart of Examples 1-3 refer to figure 1 . Among them, Example 1 is used to illustrate the preparation of CuCl and gold and silver enrichment from waste printed circuit boards, Example 2 is used to illustrate the leaching and recovery of silver, and Example 3 is used to illustrate the leaching and recovery of gold.

[0028] Example 1

[0029] a. Pretreatment of waste printed circuit boards: Crush the waste circuit boards to obtain circuit board powder of less than 30 meshes.

[0030] b. Selective dissolution of copper and enrichment of gold and silver: CuSO 4 ·5H 2 O and saturated sodium chloride were mixed in a mass-volume ratio of 1:5 (g / mL), and the CuSO 4 ·5H 2 After the O is completely dissolved, add the circuit board powder to control the copper and CuSO in the circuit board powder 4 ·5H 2 The molar ratio of copper ions in the O / NaCl mixed solution was 0.7:1-1.2:1, and the reaction was stirred at a temperature of 60° C. for 3...

Embodiment 2

[0034] Example 2 continued to use the gold and silver enriched residue obtained in Example 1, namely residue I. Ammonia solution of 0.1-1.5mol / L was added to the gold and silver enriched slag obtained in step b of Example 1, and the liquid-solid ratio of the ammonia solution to the gold and silver enriched slag was 100:1, and the reaction temperature was 25-75 mol / L. ℃, the reaction time is 2 minutes to 6 hours, and the silver solution and gold enriched slag are obtained after filtration.

[0035] For the data of silver leaching recovery rate in this example, see image 3 . from image 3 It can be seen that the concentration of ammonia water, leaching time and temperature have obvious effects on the leaching of silver. When the ammonia concentration is greater than 0.5, the silver leaching rate can reach more than 80%. The leaching rate is positively correlated with time and temperature. Under the conditions of 25℃, 50℃, and 75℃, the silver leaching rate can reach more tha...

Embodiment 3

[0037] In Example 3, the gold-enriched slag obtained in Example 2 was used. The gold-enriched slag obtained in Example 2 was added to Cu 2+ –NH 3 –Na 2 S 2 O 3 The mixed solution was stirred and leached, in which Na 2 S 2 O 3 The concentration is 0.09-0.13mol / L, NH 3 The concentration is 0.1-0.4mol / L, Cu 2+ Concentration 0.015-0.03mol / L, Cu 2+ –NH 3 –Na 2 S 2 O 3 The liquid-solid ratio of the mixed solution and the gold-enriched slag is 100:1, the reaction temperature is 20-60° C., and the gold solution is obtained by filtration after the reaction time.

[0038] For the data of gold leaching recovery rate in this example, see Figure 4 , Figure 5 . from Figure 4 It can be seen that Cu 2+ –NH 3 –Na 2 S 2 O 3 The concentration of the different components in the gold all affect the leaching rate of gold. when Na 2 S 2 O 3 The concentration is 0.1mol / L, 0.125mol / L, NH 3 Concentrations are 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L, Cu 2+ Concentration 0.0...

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Abstract

The invention discloses a method for recycling copper, silver and gold step by step by using a waste printed circuit board. The method comprises the following steps: a, pretreatment of the waste printed circuit board: a, crushing of the waste printed circuit board; b, mixing copper sulfate with a saturated sodium chloride solution, adding the circuit board powder, stirring for reaction, and filtering; c, filtering the filtrate in the step b into deionized water, and standing and precipitating to obtain cuprous chloride; d, adding the gold and silver enriched slag obtained in the step b into an ammonia solution, stirring and leaching, and filtering to obtain a silver solution and gold enriched slag; and e, adding the gold-enriched slag obtained in the step d into a Cu < 2 + >-NH3-Na2S2O3 mixed solution, stirring and leaching to obtain a gold solution. According to the method, copper in the waste circuit board is converted into cuprous chloride in the cuprous chloride synthesis process, meanwhile, enrichment of Ag and Au is achieved, step-by-step recycling of copper, gold and silver is achieved, and the method is a simple and environment-friendly method for recycling valuable metal from the waste circuit board.

Description

technical field [0001] The invention relates to a method for recovering copper, silver and gold from waste and old printed circuit boards, in particular to a method for recovering copper, silver and gold step by step by using waste and old printed circuit boards. Background technique [0002] Among different electronic and electrical products, the proportion of circuit boards varies from 2% to 20%. It is estimated that with a proportion of 5%, about 2 million tons of waste printed circuit boards are generated every year in the world. 50-1 million tons. The main components of waste printed circuit boards include three parts: metal, plastic and oxide. Among them, copper, gold and silver in waste printed circuit boards account for more than 95% of the total recycling value of printed circuit boards, and have extremely high recycling value. Waste printed circuit boards are usually first subjected to pretreatment processes such as crushing, sorting or incineration, high tempera...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B11/00C22B15/00
CPCC22B7/006C22B7/008C22B11/046C22B15/0089C22B15/0091Y02P10/20
Inventor 张志远张付申
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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