Selenium Polymer Gold Extraction Selectivity
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Solution Overview
Problem
Current methods for extracting gold from electronic waste, such as cyanide extraction and organic phase extraction, are environmentally harmful due to toxic byproducts and complex post-treatment requirements, and struggle with selective recovery amidst other metals like copper and nickel.
Innovation Solution
A method involving the use of a selenium-containing compound and isocyanate, with a tin-based catalyst, to form a selenium-containing polymer or porous material that selectively extracts and enriches gold by immersion in an aqueous solution, followed by removal of the selenium material to obtain high-purity gold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cyanide extraction method is used, then gold extraction efficiency is improved, but environmental harm increases due to toxic cyanide waste
Solution Approach 1:
The patent converts the harmful cyanide extraction method into a beneficial selenium-based extraction method. The selenium-containing compound selectively binds with gold ions, forming a stable complex that can be easily separated. This transforms the previously harmful toxic waste problem into an environmentally friendly extraction process that maintains high gold recovery efficiency while eliminating cyanide pollution.
Solution Approach 2:
The patent changes the chemical parameter of the extraction agent from cyanide to selenium-containing compound. By altering the chemical nature of the extracting agent, the method achieves selective gold extraction without producing toxic waste. The selenium compound forms specific complexes with gold ions, enabling efficient extraction while being environmentally benign.
2Productivity
If organic phase extraction method is used, then gold extraction is achieved, but post-treatment complexity increases due to large amount of organic solvents
Solution Approach 1:
The patent extracts and eliminates the organic solvent step from the extraction process. By using a water-soluble selenium-containing compound, the method directly extracts gold from aqueous solutions without requiring organic phase separation. This simplifies the entire process by removing the complex post-treatment steps needed to remove and recover organic solvents.
Solution Approach 2:
The patent introduces a selenium-containing compound as an intermediary agent that facilitates gold extraction without requiring organic solvents. This intermediary forms water-soluble complexes with gold ions, enabling direct extraction and simplifying the overall process by eliminating the need for organic phase extraction and subsequent solvent removal steps.
3Productivity
If existing extraction methods are used, then gold can be extracted, but selectivity decreases due to presence of other metals like copper and nickel
Solution Approach 1:
The patent applies local quality by making the extraction agent specifically selective for gold ions. The selenium-containing compound has a particular affinity for gold ions over other metals like copper and nickel. This localized selectivity allows the extraction process to target only gold while leaving other metals unaffected, achieving high purity gold extraction in the presence of multiple metal ions.
Solution Approach 2:
The patent converts the non-selective extraction problem into a selective extraction solution. By using selenium-based chemistry, which naturally has high affinity for gold, the method transforms the challenge of separating gold from other metals into an advantage. The selenium compound selectively complexes with gold ions, enabling efficient separation and purification even in complex multi-metal solutions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient, selective, and environmentally friendly gold recovery from electronic waste, reducing the need for toxic chemicals and complex post-treatment, with high gold extraction efficiency and selectivity, and can be applied to solutions with multiple metal ions.
Implementation Method 1
mixing an isocyanate and a selenium-containing compound of a formula of HO—R—Se—R—OH in a solvent according to a mass ratio of the isocyanate to the selenium-containing compound of (0.2 to 2):1 to obtain a mixture system
Implementation Method 2
adding a tin-based catalyst in an amount of 20 to 100 μL per 1 g of the selenium-containing compound into the mixture system to activate a reaction
Implementation Method 3
immersing the selenium-containing polymer in an aqueous solution containing gold ions to allow gold to be extracted from the aqueous solution
Data Source
AI summary
A method for extracting and enriching gold with a selenide includes: mixing an isocyanate and a selenium-containing compound of a formula of HO—R—Se—R—OH in a solvent to obtain a mixture system, where R is selected from linear or branched C2 to C11 alkylene groups; adding a tin-based catalyst into the mixture system to activate a reaction, drying the mixture system after the reaction, and obtaining a powdery selenium-containing polymer by grinding; immersing the selenium-containing polymer in an aqueous solution containing gold ions to allow gold to be extracted from the aqueous solution; and removing the selenium-containing polymer attached to a surface of extracted gold, thereby obtaining an extracted and enriched gold.