Supramolecular Gold Stripping via Alpha-Cyclodextrin

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Solution Overview

Problem

Current gold stripping processes in gold mining require harsh conditions such as high temperatures, high pressures, and toxic chemicals, which are environmentally detrimental and costly.

Innovation Solution

A method using a surface-bound linear gold anion and a molecular receptor, specifically α-cyclodextrin, to transfer gold anions from activated carbon into an aqueous solution at mild temperatures, facilitating gold recovery through electrolysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If harsh conditions (high temperature, high pressure, concentrated cyanide and hydroxide solution) are used for gold stripping from activated carbon, then gold recovery efficiency is improved, but environmental harm and operational complexity increase

Engineering Contradiction:

Improvegold recovery efficiencyVSAvoidenvironmental harm

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the parameters of the stripping process by using a molecular receptor that enables gold stripping at mild temperatures (20-40°C) and atmospheric pressure, replacing the conventional harsh conditions of high temperature (95-140°C), high pressure (70-400 kPa), and concentrated cyanide/hydroxide solutions. This parameter change maintains gold recovery efficiency while eliminating environmental harm associated with harsh chemicals and extreme conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces a molecular receptor as an intermediary substance that selectively binds to the linear gold anion Au(CN)2−. This receptor acts as a mediator between the activated carbon and the gold complex, enabling selective stripping of gold under mild conditions without requiring harsh chemicals. The receptor's specific binding affinity for the gold complex allows efficient recovery while avoiding the use of toxic concentrated cyanide and hydroxide solutions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If harsh conditions (high temperature, high pressure) are used for gold stripping, then gold recovery efficiency is improved, but energy consumption increases

Engineering Contradiction:

Improvegold recovery efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention fundamentally changes the operational parameters by conducting the stripping process at mild temperatures (20-40°C) and atmospheric pressure, eliminating the need for high temperature (95-140°C) and high pressure (70-400 kPa) equipment. This parameter change dramatically reduces energy consumption for heating and pressurization while maintaining effective gold recovery through the molecular receptor's selective binding

Inventive Principle:

Principle #35Parameter changes

3Productivity

If concentrated cyanide and hydroxide solution are used for gold stripping, then gold recovery efficiency is improved, but toxicity and environmental impact increase

Engineering Contradiction:

Improvegold recovery efficiencyVSAvoidtoxicity

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The molecular receptor serves as a non-toxic intermediary that selectively binds to the gold complex Au(CN)2−, replacing the need for concentrated cyanide and hydroxide solutions. The receptor's specific affinity for the linear gold anion enables efficient gold recovery without introducing additional toxicity or environmental harm from harsh chemicals

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention employs a molecular receptor that can be used in aqueous solution under mild conditions, replacing expensive and hazardous concentrated cyanide and hydroxide solutions. The receptor approach allows for safer, more environmentally friendly operations while maintaining gold recovery efficiency

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 gold stripping at room temperature with environmentally benign reagents, reducing energy consumption and environmental impact while maintaining high gold recovery efficiency.

Implementation Method 1

the molecular receptor is α-cyclodextrin (α-CD)... transferring the linear gold anion from the surface into the solution

Methodology Applied

Scientific EffectHost-guest inclusion complexation:

Implementation Method 2

an electrolyte comprising the molecular receptor and a linear gold anion... recovering the gold from the solution

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentUS20240375084A1Supramolecular gold stripping from activated carbon using alpha-cyclodextrin

Publication Date: 2024.11.14 NORTHWESTERN UNIV

AI summary

Disclosed herein are compositions, methods, and systems for supramolecular gold stripping where the composition comprises a surface-bound, linear gold anion and a solution comprising a molecular receptor that facilitates the transfer of the linear gold anion from the surface to the solution.