Progressive Electrolysis for Acidic Etching Waste Recycling
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Solution Overview
Problem
Current electrolysis processes for recycling acidic etching waste solutions from PCB production are inefficient, leading to significant chloride ion loss, high energy consumption, and corrosion of metallic copper, which results in a loose and rough copper layer.
Innovation Solution
The method involves progressive electrolysis using multiple electrolytic cells with separate anode and cathode chambers, where the cathode electrolyte undergoes electrolytic treatment and is then oxidized to regenerate a copper-etching agent, reducing copper ion concentration and minimizing copper corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If direct electrolysis is used to extract copper from acidic etching waste solution, then copper recovery is achieved, but chloride ion loss is large and oxidant supplementation is required
Solution Approach 1:
The electrolysis process is divided into two distinct stages: first, electrolytic treatment to reduce copper-etching agent concentration; second, oxidative regeneration to recover copper. This segmentation allows each stage to optimize for its specific function, preventing chloride ion loss while maintaining copper recovery efficiency.
Solution Approach 2:
The copper-etching agent concentration is reduced through electrolysis before the oxidative regeneration step. This preliminary action prepares the solution by removing excess copper-etching agent, which prevents chloride ion loss during the subsequent copper recovery process.
2Loss of energy
If acidic etching waste solution is added to cathode chamber for electrolysis, then oxidant addition is reduced, but copper-etching agent corrodes metallic copper electroprecipitated at cathode
Solution Approach 1:
The process separates the electrolysis function (performed in anode chamber) from the copper electroprecipitation function (performed in cathode chamber after copper-etching agent removal). This segmentation ensures that copper electroprecipitation occurs in a solution without corrosive copper-etching agent, preventing copper layer corrosion.
Solution Approach 2:
The copper-etching agent concentration is reduced through electrolysis before copper electroprecipitation occurs. This preliminary reduction of copper-etching agent concentration eliminates the corrosive effect on the metallic copper layer during electroprecipitation.
3Manufacturing precision
If copper electroplating brightener is added to cathode electrolyte, then copper layer smoothness is improved, but new impurities are introduced preventing 100% recycling
Solution Approach 1:
The system uses the electrolysis process itself to achieve copper electroprecipitation without requiring external additives like copper electroplating brighteners. The electrolysis current directly facilitates copper deposition, eliminating the need for additional chemicals that would introduce impurities and prevent 100% recycling.
Solution Approach 2:
The harmful copper-etching agent is extracted and removed from the solution through electrolysis before copper electroprecipitation. This extraction eliminates the need for copper electroplating brighteners, as the cleaned solution allows direct copper deposition without corrosion issues.
4Productivity
If multiple electrolytic cells are used for progressive electrolysis, then copper recovery and recycling are improved, but device complexity increases
Solution Approach 1:
The electrolysis system is segmented into multiple cells with distinct functions: anode chamber for electrolytic treatment and cathode chamber for copper recovery. This functional segmentation enables progressive electrolysis, improving copper recovery rate while maintaining manageable system complexity through modular design.
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 effectively recovers copper from acidic etching waste solutions, reduces energy consumption, prevents copper corrosion, and allows for the 100% recycling of etching waste solutions, thereby lowering production costs and environmental pollution.
Implementation Method 1
a method and device for recycling an acidic etching waste solution through progressive electrolysis
Implementation Method 2
an oxidant, hydrochloric acid, and/or ferric chloride and an optional additive need to be supplemented to an etching solution, such that cuprous chloride and ferrous chloride can be oxidatively regenerated into cupric chloride and ferric chloride respectively
Data Source
AI summary
Disclosed is a method and device for recycling an acidic etching waste solution through progressive electrolysis. The method includes: introducing at least one electrolytic cell A, where the electrolytic cell A is divided into an anode chamber and a cathode chamber; during an electrolysis operation, a cathode electrolyte of the electrolytic cell A includes the acidic etching waste solution; and introducing at least one electrolytic cell B, where the electrolytic cell B is divided into an anode chamber and a cathode chamber; the cathode electrolyte of the electrolytic cell B includes a cathode electrolyte undergoing an electrolytic treatment from the electrolytic cell A or a mixed solution of the cathode electrolyte undergoing the electrolytic treatment with the acidic etching waste solution. With the present disclosure, PCB manufacturers can avoid the introduction of new impurities and reduce the electrolysis energy consumption during an electrolytic copper recovery process.