Tetrazole Additive for High-Purity Copper Refining

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Solution Overview

Problem

Conventional copper electrolytic refining methods struggle to reduce silver and chlorine concentrations in high-purity copper, leading to impurity deposition and purity degradation, and are time-consuming and inefficient.

Innovation Solution

An additive comprising tetrazoles as a silver and chlorine reducing agent, combined with polyethylene glycol or non-ionic surfactants and polyvinyl alcohol derivatives, is added to the copper electrolyte to selectively precipitate silver and chlorine ions, reducing their concentrations and improving copper purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chloride ions are added to the copper electrolyte to precipitate silver ions, then silver removal is improved, but chlorine concentration in the deposited copper increases and purity deteriorates

Engineering Contradiction:
Improvesilver removal efficiencyVSAvoidchlorine concentration in deposited copper
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical form of chlorine from ionic chloride (Cl-) to molecular chlorine (Cl2) by introducing oxygen and controlling oxidation conditions. This parameter change allows chlorine to be removed as gas while preventing its incorporation into the copper deposit, thus maintaining both silver removal efficiency and copper purity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition by converting dissolved chlorine ions into gaseous chlorine through oxidation and heating. The chlorine gas then escapes from the electrolyte solution, effectively removing chlorine without contaminating the deposited copper with chloride ions

Inventive Principle:
Principle #36Phase transitions

2Manufacturing precision

If conventional electrolysis methods are used to produce high-purity copper, then copper purity is improved, but production time and process complexity increase significantly

Engineering Contradiction:
Improvecopper purityVSAvoidelectrolysis time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary removal of silver and chlorine from the electrolyte before the main copper deposition process. By pre-treating the electrolyte with oxidation to precipitate silver as AgCl and converting chlorine to gas form, the subsequent electrolysis produces high-purity copper faster without requiring multiple stages or extended processing time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts harmful impurities (silver and chlorine) from the electrolyte system before they can contaminate the copper deposit. Silver is extracted as precipitated AgCl particles, and chlorine is extracted as evolved gas, allowing the main electrolysis process to focus solely on copper deposition with reduced time and complexity

Inventive Principle:
Principle #2Taking out (Extraction)

3Shape

If polyethylene glycol or polyvinyl alcohol is added as smoothing agent, then surface quality is improved, but silver and chlorine concentrations in the deposited copper cannot be reduced sufficiently

Engineering Contradiction:
Improvesurface smoothnessVSAvoidimpurity concentration
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent merges multiple functions into a unified electrolyte composition system that combines smoothing agents (polyethylene glycol or polyvinyl alcohol) with oxidation-based impurity removal mechanisms. This integrated approach achieves both surface smoothing and sufficient impurity reduction simultaneously, rather than treating them as separate conflicting requirements

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite electrolyte system containing multiple components working together: copper sulfate for copper deposition, smoothing agents for surface quality, and oxidation conditions for impurity removal. This composite approach enables simultaneous achievement of surface smoothness and low impurity concentrations that cannot be achieved with single additives

Inventive Principle:
Principle #40Composite materials

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

The additive achieves a significant reduction in silver and chlorine concentrations to 1 ppm by mass or less and 50 ppm by mass or less, respectively, while maintaining the copper's mechanical properties and preventing warpage and peeling from the cathode substrate.

Implementation Method 1

a silver and chlorine reducing agent of electrolytic copper which is formed of tetrazoles which is one of a tetrazole and a tetrazole derivative

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 2

a silver and chlorine reducing agent of electrolytic copper which is formed of tetrazoles

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

performing electrolysis in a copper sulfate aqueous solution, then performing electrolysis again in a copper nitrate aqueous solution

Methodology Applied
Scientific EffectElectrodeposition: Electrodeposition

Data Source

PatentUS10428434B2Additive for high-purity copper electrolytic refining, method of producing high-purity copper, and high-purity electrolytic copper
Publication Date: 2019.10.01 MITSUBISHI MATERIALS CORP

AI summary

The present invention provides an additive for high-purity copper electrolytic refining, a method of producing high-purity copper, and a high-purity electrolytic copper. This additive of the present invention for high-purity copper electrolytic refining can be added to a copper electrolyte in copper electrolytic refining. The additive includes a silver and chlorine reducing agent of electrolytic copper which is formed of tetrazoles which is one of a tetrazole and a tetrazole derivative.