A two-step method for the recovery of copper and gold from waste electronic materials

A technology for recovering copper and materials, applied in the field of acid thiourea leaching gold system, zero-valent copper and gold, acidophilic microbial pretreatment-acid thiourea leaching zero-valent copper and gold, which can solve many disadvantages of gold extraction Inability, environmental pollution, toxic cyanide and other problems, to achieve the effect of non-toxic gold leaching system, no pollution to the environment, and low cost

Active Publication Date: 2016-04-20
SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, cyanide is poisonous, and if it is used to extract gold from electronic waste, it will definitely bring about very serious environmental pollution problems.
Non-cyanide methods such as thiosulfate method, halogenation method, lime sulfur method, etc. cannot be applied in industrial production due to their shortcomings in gold extraction.

Method used

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  • A two-step method for the recovery of copper and gold from waste electronic materials

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Experimental program
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Effect test

Embodiment 1

[0024] Take 40g containing gold 1.108mg / g, silver 7.62mg / g, iron 85.67mg / g, copper 223.24mg / g, zinc 32.21mg / g, tin 62.25mg / g, nickel 48.39mg / g The mobile phone board is crushed to powder with a particle size of less than 2mm. Prepare iron-free 9k medium, adjust the initial pH to 2.0 with 2 mol / L sulfuric acid, and inoculate about 10% by volume of activated Acidithiobacillus ferrooxidans into iron-free 9k medium. The solid material was added at a solid-liquid mass ratio of 1:50, and microbial leaching was carried out under the condition of 30 ℃ and mechanical stirring. The leaching rate of copper reached more than 95% after several days. Take 5g of filter residue and add it to the acid thiourea leaching system, wherein the pH of the system is 1.0, the concentration of sulfuric acid is 1g / L, the amount of thiourea is 4g / L, the amount of sodium hexametaphosphate is 1.0g / L, and the mechanical After stirring for 1 h, the leaching rate of gold reached 90.26%.

Embodiment 2

[0026]Take 50g containing gold 1.128mg / g, silver 10.62mg / g, iron 92.17mg / g, copper 277.68mg / g, zinc 19.49mg / g, tin 55.49mg / g, nickel 42.69mg / g The mobile phone board is crushed to powder with a particle size of less than 1mm. Prepare iron-free 9k medium, adjust the initial pH value to 1.6 with 5mol / L sulfuric acid, inoculate 15% Acidithiobacillus ferrooxidans, and add solid materials at a solid-liquid mass ratio of 1:100 for microbial leaching , the leaching rate of copper reaches more than 95%. Take 5g of filter residue and add it to the acid thiourea leaching system, wherein pH=1.5, sulfuric acid concentration is 3g / L, thiourea dosage is 8g / L, sodium hexametaphosphate dosage is 1.0g / L, and mechanical stirring is carried out at 30°C 1h, the gold leaching rate reached 95.15%.

Embodiment 3

[0028] Take 100g of mobile phone boards containing 1.108mg / g of gold, 7.62mg / g of silver, 223.24mg / g of copper, 32.21mg / g of zinc, 62.25mg / g of tin and 48.39mg / g of nickel, and crush them to particle size Powder smaller than 1mm. Prepare iron-free 9k medium, adjust the initial pH value to 1.5, inoculate about 10% of the volume of Acidithiobacillus ferrooxidans that has been activated for 2 days, and add solid materials according to the solid-liquid mass ratio of 1:50 for microorganisms. Leaching, the leaching rate of copper reaches more than 95%. Take 1g of filter residue and add it to the acid thiourea leaching system, wherein pH=1.5, sulfuric acid concentration is 4g / L, the amount of thiourea is 12g / L, and the amount of sodium hexametaphosphate is 1.0g / L. After stirring for 1 h, the leaching rate of gold reached 90.51%.

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Abstract

The invention belongs to the fields of chemical industry and hydrometallurgy and in particular relates to a method for recycling copper and gold from a waste electronic material through a two-step method. The method comprises the following steps: firstly leaching ordinary metals out of the material in the presence of acidophilic microorganisms, recycling the copper from an acidophilic microorganism leaching solution by using an extraction electrolysis process; and subsequently leaching zero-valence gold out of residue in an acidic thiourea system and recycling thiourea gold by using active carbon or ion exchange resin method. The method has the advantages that the environment of the process for leaching copper out of the microorganisms is environment-friendly, pollution-free and low in cost; the materials can be recycled in a closed cycle mode; by virtue of the pretreatment materials of the microorganisms, higher gold-leaching efficiency of the acidic thiourea is achieved, a faster speed is achieved; reagents used in the gold-leaching system are non-toxic; and moreover, the copper-leaching efficiency can reach over 95% and the gold-leaching efficiency can reach over 90%.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and hydrometallurgy, and relates to a method for acidophilic microorganism pretreatment-acidic thiourea leaching of zero-valent copper and gold. Specifically, it relates to an efficient and stable acid thiourea gold leaching system, and a method for acidophilic microorganism pretreatment-recovering zero-valent copper and gold in acid thiourea materials. Background technique [0002] Waste electronic materials such as discarded mobile phone boards, discarded computer boards, memory sticks, and scraps of gold-plated printed circuit boards contain zero-valent copper and gold with high recycling value. Heat treatment technology hinders its industrial application due to expensive equipment, non-metallic materials can not be recycled, serious environmental pollution and other problems. The traditional cyanidation method and the aqua regia method for dissolving gold are not suitable for the re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B15/00C22B11/00
CPCY02P10/20
Inventor 白建峰白静张承龙王景伟苑文仪
Owner SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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