Electrochemical Flotation Control for Selective Sulphide Depression

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Solution Overview

Problem

Conventional methods for depressing pyrite and other sulphides in mineral flotation using chemical depressants are costly, environmentally hazardous, and lack specificity, leading to high reagent consumption and inefficient mineral separation.

Innovation Solution

An electrochemical process that applies electric potential to mineral particles to alter their hydrophilicity, reducing the need for chemical depressants and enabling precise control over flotation conditions, allowing for selective depression of unwanted sulphides and recovery of valuable minerals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chemical depressants are used to depress pyrite and other sulphides in flotation, then mineral separation can be achieved, but reagent consumption increases and environmental harm worsens

Engineering Contradiction:
Improvemineral separation efficiencyVSAvoidenvironmental harm from chemical depressants
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical depression mechanisms with electrochemical oxidation. An electrochemical reactor applies controlled electric potential to oxidize pyrite and unwanted sulphides, making them hydrophilic and preventing their flotation. This substitutes chemical reagents (cyanide, metabisulphite, etc.) with an electrochemical field, eliminating the need for harmful chemical depressants while achieving the same separation effect.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the controlling parameter from chemical concentration to electrochemical potential. By controlling the electric potential in the electrochemical reactor, the oxidation level of sulphide minerals can be precisely adjusted. This allows selective depression of pyrite and other unwanted sulphides without the need to manage chemical reagent dosages, improving environmental performance while maintaining separation efficiency.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If chemical depressants are used to depress pyrite and other sulphides in flotation, then mineral separation can be achieved, but reagent costs and process complexity increase

Engineering Contradiction:
Improvemineral separation efficiencyVSAvoidprocess complexity from multiple chemical reagents
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces multiple chemical depression systems with a single electrochemical reactor. Instead of managing multiple chemical reagents (cyanide, metabisulphite, sulphite, lime, etc.), the system uses one electrochemical unit that applies controlled electric potential to achieve the same depression effect. This simplifies the process flow and reduces operational complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrochemical reactor serves multiple functions: it oxidizes pyrite, oxidizes other unwanted sulphides containing arsenic/antimony/bismuth/mercury/lead, and controls their hydrophilicity. A single device replaces what previously required multiple different chemical reagents and treatment stages, reducing process complexity while maintaining comprehensive mineral separation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If chemical depressants are used to depress pyrite and other sulphides in flotation, then mineral separation can be achieved, but response time and control precision decrease

Engineering Contradiction:
Improvemineral separation efficiencyVSAvoidresponse time to process changes
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The patent changes the control parameter from chemical dosage (which has lagged response) to electric potential (which responds instantaneously). The electrochemical reactor allows real-time adjustment of oxidation levels by simply changing the applied voltage, enabling rapid response to process variations and precise control of mineral separation without the time delays associated with chemical reagent diffusion and reaction.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If conventional flotation is used to concentrate sulphide minerals, then valuable minerals can be recovered, but unwanted elements such as arsenic, antimony, bismuth, mercury and lead are also concentrated, leading to commercial penalties

Engineering Contradiction:
Improverecovery of valuable mineralsVSAvoidconcentration of noxious elements
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by selectively oxidizing specific mineral surfaces through controlled electrochemical potential. The electrochemical reactor creates different oxidation conditions that selectively affect pyrite and unwanted sulphide surfaces, making them hydrophilic and preventing their association with valuable minerals during flotation. This local surface modification achieves separation based on surface properties rather than bulk composition, allowing recovery of valuable minerals while leaving unwanted elements behind.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses electrochemical oxidation to selectively modify the surface properties of minerals containing unwanted elements (arsenic, antimony, bismuth, mercury, lead). By controlling the electric potential, the system oxidizes these unwanted sulphides to make them hydrophilic, preventing their flotation with valuable minerals. This eliminates the need for chemical depressants that would otherwise be required to achieve the same selective separation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 process enhances mineral separation efficiency, reduces reagent consumption, minimizes environmental impact, and optimizes grade-recovery ratios by applying electric potential independently of pH, enabling faster response times and improved mineral recovery.

Implementation Method 1

The process and reactor that replace, minimise, optimise or compliment the use of depressants and other chemical reagents... The choice of electric potential enables using any value of potential... enables varying the pH and the electrochemical potential in an independent fashion

Methodology Applied
Scientific EffectElectrochemical potential application: Electric Field

Implementation Method 2

a main objective to concentrate the mineral/s of interest consists in the selective depression of pyrite (sulphur and iron mineral)... the depression of pyrite and other sulphides to be discarded is achieved by the addition of chemical depressants

Methodology Applied
Scientific EffectElectrochemical oxidation: Oxidation

Implementation Method 3

The adhesion of the particles to the bubbles happens mainly as a function of the hydrophobicity of the mineral surface. The most hydrophobic particles tend to adhere to the bubbles, thereby floating, while the more hydrophilic ones tend to get surrounded by liquid, thereby being depressed

Methodology Applied
Scientific EffectHydrophobic adhesion: Hydrophobe

Implementation Method 4

Flotation is used to concentrate or separate mineral species through the selective adhesion of mineral particles of each species to air bubbles. These bubbles float up to the surface of the liquid, forming froth that is collected as the product of such process

Methodology Applied
Scientific EffectFroth flotation: Froth Floatation

Data Source

PatentEP3278879B1Process for the depression of iron sulphides and other disposable elements in the concentration of mineral by flotation and electrochemical reactor
Publication Date: 2025.12.24 LAIN TECH LTD
  • EP3278879B1 patent drawingFigure 1~2
  • EP3278879B1 patent drawingFigure 3~4
  • EP3278879B1 patent drawingFigure 5~6

AI summary

Process for the depression of iron sulphides and other disposable elements in the concentration of mineral by flotation and electrochemical reactor. The proposed invention represents a method based on the action of electrodes over the mineral, which can replace, compliment or minimise the consumption of chemical reagents, as well as improving their effect.