AC Superposition on DC Electrolysis for Copper Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The copper industry faces challenges in maintaining the quality of copper deposition during electrowinning and electrorefining processes due to limitations in current density, temperature, and flow rate, leading to high operational costs and quality issues, particularly with the restriction of current densities and the phenomenon of anode passivation, which hinders the efficient use of technologies like air sparging and EMEW in mass production.
Innovation Solution
The solution involves superimposing alternating current (AC) on the direct current (DC) in electrolytic cells by connecting an AC source between two consecutive cells in series, incorporating an inductor and a capacitor to filter and manage the current, allowing for efficient ion agitation without altering the existing infrastructure, and using a frequency range of 5 to 10 kHz to optimize the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current density is increased to improve production, then productivity increases, but the quality of copper deposited deteriorates
Solution Approach 1:
The patent applies periodic action by superimposing an alternating current (AC) signal on the direct current (DC) used in electrolysis. The AC component periodically perturbs the electric field at the electrode surface, preventing concentration polarization and enabling higher average current densities while maintaining deposit quality. This periodic modulation allows the system to operate beyond the traditional current density limits without sacrificing copper quality.
2Manufacturing precision
If temperature is increased to improve ion mobility and maintain copper quality, then manufacturing precision is maintained, but energy consumption increases
Solution Approach 1:
The patent replaces the thermal mechanism (heating to improve ion mobility) with an electrical mechanism (AC superposition to enhance ion transport). Instead of relying on increased temperature to improve ion mobility at the electrode surface, the AC signal directly modulates the electric field, creating periodic ion migration that enhances transport efficiency without the energy cost of heating. This substitution eliminates the need to operate at elevated temperatures above 45°C while maintaining deposit quality.
3Manufacturing precision
If flow rate is increased to improve ion availability, then manufacturing precision is maintained, but device complexity and operational cost increase
Solution Approach 1:
The patent applies self-service by using the electrolytic cells themselves to generate the desired flow enhancement effect. The AC superposition creates periodic expansion and contraction of the electric field within the existing electrolyte circulation system, inducing natural convection currents that enhance ion transport to the electrodes. This eliminates the need for separate agitation devices or increased pump capacity, as the system uses its own electric field to create the necessary fluid motion.
4Manufacturing precision
If AC superposition is implemented to improve ion transport, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent merges the AC signal generation and delivery functions into the existing DC power supply system. The AC component is superimposed on the DC current through the same electrical connection path that already exists for delivering power to the electrolytic cells. This integration approach avoids requiring separate AC power supplies, additional wiring harnesses, or complex control systems, as the modification is implemented within the existing electrical infrastructure.
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 approach enhances the quality of copper deposition by improving ion transport phenomena near the electrode, reducing operational costs, and maintaining the physical quality of copper while minimizing disruptions to the existing plant operations by using existing components and designs from induction heating sources.
Implementation Method 1
a model can simply consider the Helmholtz layer as a capacitor composed of a metallic plate (the electrode) and a non-metallic plate consisting of high concentration of ions in the electrolyte
Implementation Method 2
from the diffuse layer to the middle of the solution, ion transport phenomena occur, like migration due to the applied electric field
Implementation Method 3
The electric current generated by the rectifier causes the dissolved copper in the electrolyte to deposit on the cathode surface; this process according to Faraday's law is proportional to the circulating electrical current, and results in metallic copper of high purity
Implementation Method 4
The copper industry uses electric current rectifiers to produce copper, where a circulating electrolyte has copper dissolved in it
Data Source
AI summary
A process for superimposing AC over DC, which feeds a group of electrolytic cells for electrowinning or electrorefining copper and other products, characterized by (a) incorporating an inductor which is connected between the terminals of two consecutive middle cells of the group of electrolytic cells, wherein the inductor functions are to act as a filter for the AC and as conducting means for the DC; (b) incorporating a capacitor connected in parallel to the original DC source, wherein the capacitor functions are to act as conducting means for the AC and as a filter for the DC; and (c) incorporating an AC source connected to the terminals of an inductor installed in the middle point of the group of electrolytic cells.