Process for recovering metal from electronic waste

A technology of electronic waste and metal, applied in chemical instruments and methods, improvement of process efficiency, transportation and packaging, etc., can solve problems such as expensive, highly toxic, and non-recyclable

Pending Publication Date: 2020-06-19
MINT INNOVATION LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hydrometallurgical methods generally involve the use of strong acids or cyanide-based solutions to leach metals, which are highly toxic, expensive, and not recyclable
The intermingling of e-waste as a feedstock also makes it difficult to use these existing technologies in an economically viable manner

Method used

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  • Process for recovering metal from electronic waste
  • Process for recovering metal from electronic waste
  • Process for recovering metal from electronic waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0252] Basic Example 1 Biosorption of Gold Dissolved in Aqua Regia

[0253] Materials and methods:

[0254] Microbial cultures are grown under sterile conditions, but then processed using non-sterile solutions and equipment.

[0255] 1. Incubate and grow 25 mL of nutrient broth (0.5% peptone, 0.3% yeast extract) with C. metalloreta CH34 (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH#2839) at 30°C at about 200 rpm for at least 16 hours to the stationary phase.

[0256] 2. The culture was centrifuged at 3100 rcf for 15 minutes, the supernatant was discarded, and the pellet (about 0.1 g) was resuspended in 30 mL of 0.1 M sodium perchlorate for washing. This centrifugation / washing step was repeated one more time with a volume of 10 mL.

[0257] 3. The culture was centrifuged again as above, the supernatant was discarded, and the pellet was resuspended in 25 mL of 0.1 M sodium perchlorate, 25 μM chloroauric acid (about 5 ppm Au), pH 4 (with hydrogen NaO adjustment...

Embodiment 3

[0321] The lixiviant of embodiment 3B dissolved gold

[0322] Materials and methods:

[0323] Printed circuit boards were collected from discarded desktop computers, sections with gold-plated connection pins were cut from the boards, and used as e-scrap stock models.

[0324] 1. Prepare a lixiviant solution for gold as follows:

[0325] a. Iodine based lixiviant: 0.1 M iodine, 37.5 mM potassium iodide; make up in water and let stand for 2 hours before use.

[0326] b. Acetic acid / peroxide based lixiviant: 1.5M hydrochloric acid, 0.6M hydrogen peroxide, 0.6M calcium chloride; make up in glacial acetic acid and stir for 30 minutes before use. This lixiviant is similar to that described in WO 2016 / 168933 A1 (Foley et al., 2016-10-27 (27-10-16)).

[0327] c. Acetic acid / hypochlorite based lixiviant: 0.7M hydrochloric acid, 0.25M calcium hypochlorite; make up in glacial acetic acid.

[0328] d. Acetic acid / chlorine based lixiviant: 0.48M hydrochloric acid made up in glacial ace...

Embodiment 4

[0353] Example 4A Dissolution of gold and leaching of base metals from ground printed circuit boards

[0354] Materials and methods:

[0355] As a model for e-scrap feedstock, printed circuit boards were collected from discarded desktop computers and ground to a particle size <3 mm. This powder was then sieved to obtain a <1 mm particle size fraction, which was used in subsequent experiments.

[0356] 1. To pre-treat the e-scrap powder to remove base metals, 1200 g of <1 mm finely ground e-scrap was treated with 5M sulfuric acid as an approximately 30% w / v slurry in a reactor with a mechanical stirrer at 200 rpm for approximately 16 Hour. Add 50% hydrogen peroxide dropwise until a final concentration of about 7.5% is reached.

[0357] a. This treatment was repeated and the weight of the powder obtained was reduced to 745 g.

[0358] b. 125 g of this powder were subjected to an additional treatment step with 4M sulfuric acid as a slurry of about 25% w / v in a reactor with a ...

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Abstract

The invention relates to a method for recovering precious metals from electronic waste. In particular, bio-metallurgical techniques are utilised during the process. In a first aspect, the invention provides a method of recovering one or more target metals from electronic waste, the method comprising (a) a pre-processing step comprising removing at least a portion of non-target material from the electronic waste or grinding to a preselected size particle to give pre-processed electronic waste; (b) a dissolving step comprising contacting the pre-processed electronic waste with a lixiviant such that at least a portion of the target metal(s) dissolve into the lixiviant to produce a pregnant solution; (c) a biological absorption step comprising contacting a microorganism with the pregnant solution such that at least a portion of the target metal(s) ions is biologically absorbed to the microorganism wherein the microorganism becomes metal laden and the pregnant solution becomes barren; (d) aseparating step comprising substantially separating the metal laden microorganism from the barren solution; and (e) a recovery step comprising recovery of the target metal(s) from the metal laden microorganism. In particular embodiments, the target metal is gold.

Description

[0001] field of invention [0002] The present invention relates to a method for recovering at least one precious metal from electronic waste. In particular, biometallurgical techniques are used in this process. Background technique [0003] There are many materials containing trace metals in the world, including aqueous solutions and solid materials. However, recycling these metals in an efficient and environmentally friendly manner is challenging due to the rarity of metallic components relative to nonmetallic substrates. For example, the removal of toxic metal ions from aqueous liquid waste streams is an important challenge for many industries. [0004] Similarly, as the grades of ores used to mine and refine primary metals decrease, there is increasing interest in obtaining metals from source materials such as low-grade ores, smelter tailings, and electronic scrap. However, recovery of metals from these feedstocks is often economically limited. Factors that affect the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/18C22B11/00
CPCC22B11/046C22B3/18B01J2220/4868B09B3/10B09B3/80C22B3/24C22B3/065C22B3/10C22B3/22C22B7/007C22B11/06C22B11/08C22B1/005C22B3/02C22B3/08C22B3/44Y02P10/20C22B3/33C22B3/34
Inventor O·克鲁什R·惠特比R·史密斯
Owner MINT INNOVATION LTD
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