Selective Reductive Electrowinning Using Sacrificial Anolyte

Solution Overview

Problem

Current metal recovery processes, such as electro-winning, are energy-intensive and inefficient due to high over-potential water oxidation reactions, leading to reduced efficiency and impure metal recovery from waste materials like spent catalysts and batteries.

Innovation Solution

A divided electrolytic cell with a basic pH anodic chamber containing a sacrificial reductant and an acidic pH cathodic chamber, separated by an ion-conducting membrane, where a voltage is applied to reduce metal ions at the cathode and oxidize the reductant at the anode, minimizing hydrogen evolution and optimizing metal recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If traditional electrowinning is used to recover metals from aqueous solutions, then metal recovery is achieved, but high energy consumption occurs due to high over-potential water oxidation

Engineering Contradiction:

Improveenergy consumptionVSAvoidmetal recovery efficiency

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The electrolytic cell is divided into two separate compartments: an anodic chamber containing a sacrificial reductant and a cathodic chamber containing the metal ions to be recovered. This segmentation allows the oxidation reaction to occur in the anodic chamber where the sacrificial reductant is oxidized instead of water, eliminating the high over-potential problem, while the reduction of metal ions occurs in the cathodic chamber. The ion-conducting separator maintains ionic balance between compartments while preventing direct mixing of reactants and products.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sacrificial reductant is introduced as an intermediary substance in the anodic chamber. This reductant serves as a mediator that undergoes oxidation in preference to water, thereby eliminating the high over-potential water oxidation reaction. The sacrificial reductant is oxidized at the anode, producing electrons that drive the reduction of metal ions at the cathode, while the ion-conducting separator acts as an intermediary to maintain charge balance by allowing ion transport between compartments.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high voltage is applied to drive water oxidation at the anode, then metal reduction at the cathode is achieved, but hydrogen evolution occurs reducing recovery efficiency

Engineering Contradiction:

Improvemetal recovery efficiencyVSAvoidhydrogen evolution loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The electrolytic cell is divided into two separate compartments: an anodic chamber containing a sacrificial reductant and a cathodic chamber containing the metal ions to be recovered. This segmentation allows the oxidation reaction to occur in the anodic chamber where the sacrificial reductant is oxidized instead of water, eliminating the high over-potential problem, while the reduction of metal ions occurs in the cathodic chamber. The ion-conducting separator maintains ionic balance between compartments while preventing direct mixing of reactants and products.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sacrificial reductant is introduced as an intermediary substance in the anodic chamber. This reductant serves as a mediator that undergoes oxidation in preference to water, thereby eliminating the high over-potential water oxidation reaction. The sacrificial reductant is oxidized at the anode, producing electrons that drive the reduction of metal ions at the cathode, while the ion-conducting separator acts as an intermediary to maintain charge balance by allowing ion transport between compartments.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If a divided electrolytic cell with sacrificial reductant is used, then energy consumption is reduced, but device complexity increases

Engineering Contradiction:

Improveenergy consumptionVSAvoidcell structure complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The electrolytic cell is divided into two separate compartments: an anodic chamber containing a sacrificial reductant and a cathodic chamber containing the metal ions to be recovered. This segmentation allows the oxidation reaction to occur in the anodic chamber where the sacrificial reductant is oxidized instead of water, eliminating the high over-potential problem, while the reduction of metal ions occurs in the cathodic chamber. The ion-conducting separator maintains ionic balance between compartments while preventing direct mixing of reactants and products.

Inventive Principle:

Principle #1Segmentation

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 significantly reduces energy consumption and enhances the purity and efficiency of metal recovery, as demonstrated by a 77% lower energy consumption and 36% higher current efficiency compared to traditional electrowinning processes.

Implementation Method 1

an anolyte disposed within the anodic chamber, comprising a sacrificial reductant which lowers the electrochemical potential in the electrolytic cell

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

a sacrificial reductant which lowers the electrochemical potential in the electrolytic cell

Methodology Applied

Scientific EffectElectrochemical potential reduction: Redox Reactions

Implementation Method 3

the voltage or the electrical current is sufficient to reduce the at least one or more metallic ions to form at least one or more elemental metal species at the cathode

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 4

a separator disposed between the anode and the cathode to physically separate the anodic and cathodic chambers, the separator allowing the transport of ions between the anodic and cathodic chambers

Methodology Applied

Scientific EffectIon transport: Ion Exchange

Implementation Method 5

applying a voltage or an electrical current to an electrolytic cell... the voltage or the electrical current is sufficient to reduce the at least one or more metallic ions

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP2877613B1Selective reductive electrowinning method

Publication Date: 2018.03.28 OHIO UNIV

Figure 1
Figure 2
Figure 3

AI summary

A method and electrochemical cell (10) for recovery of metals is provided, where the electrochemical cell (10) includes an anode (30) disposed in an anodic chamber (25), a cathode (20) disposed in a cathodic chamber (15), an ion- conducting separator (35) disposed between the anode (30) and cathode (20) to physically separate the anodic and cathodic chambers (25, 15), a basic pH anolyte (62) containing a sacrificial reductant (60) disposed within the anodic chamber (25), an acidic pH catholyte (52) containing metal ions disposed within the cathodic chamber (15), and an electrical connection (40) between the anode (30) and the cathode (20). The method includes applying a voltage or an electrical current to an electrolytic cell (10) across the cathode (20) and the anode (30) sufficient to reduce the metal ions to form an elemental metal species at the cathode (20), and oxidize the sacrificial reductant (60) at the anode (30).