Electrolysis of Conductive Oxide Scrap for Metal Recovery
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Solution Overview
Problem
Current methods for recovering valuable metals from conductive oxide scraps, such as ITO sputtering targets, are inefficient and complicated, often resulting in impurities and unstable grain size distributions, which affect the quality of the recovered indium hydroxide and other conductive oxides.
Innovation Solution
A method involving electrolysis of scrap containing conductive oxides in a pH-adjusted electrolyte with periodically inverted anode and cathode polarity, using an insoluble electrode and the scrap as the counter electrode, to efficiently recover valuable metals as hydroxide or metal oxides, thereby simplifying the process and maintaining high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wet refining methods (acid solution process, ion exchange, solvent extraction) are used to recover valuable metals from conductive oxide scraps, then metal recovery is achieved, but the process becomes complicated and time-consuming with multiple steps including dissolution, precipitation, filtration, and neutralization
Solution Approach 1:
The patent extracts and utilizes only the essential electrolytic reduction step, removing unnecessary intermediate steps such as acid dissolution, precipitation, and filtration. The conductive oxide scraps are directly subjected to electrolysis where valuable metals are reduced and deposited on the cathode, achieving recovery in a single simplified operation.
Solution Approach 2:
The patent replaces the conventional chemical-mechanical wet refining process with an electrochemical process. Instead of using acid solutions, precipitants, and mechanical filtration, the invention uses electrolysis where electrical current directly reduces metal ions to metallic form on the cathode, substituting complex chemical operations with a controlled electrochemical reaction.
2Quantity of substance
If conventional wet refining methods are used, then metal recovery is achieved, but the recovered metal contains large amounts of impurities such as Si and Al, and the grain size distribution is unstable
Solution Approach 1:
The patent employs feedback control through periodic polarity inversion during electrolysis. By reversing the electrode polarity at intervals, the process prevents impurity accumulation, controls grain size growth, and maintains stable deposition conditions. This feedback mechanism ensures consistent metal quality and grain size distribution in the recovered material.
Solution Approach 2:
The patent applies periodic action through alternating polarity inversion during the electrolysis process. The electrode polarity is reversed at regular intervals, creating periodic deposition and dissolution cycles that prevent impurity incorporation, control crystal grain size, and ensure uniform metal recovery with stable characteristics.
3Productivity
If the sputtering operation is continued until the backing plate becomes exposed, then target utilization is maximized, but the target develops severe erosion with numerous non-eroded portions becoming scrap
Solution Approach 1:
The patent applies discarding and recovering by collecting all eroded portions and non-eroded portions of the sputtering target as scrap material. Instead of discarding the entire eroded target, the invention recovers valuable metals from both eroded and non-eroded portions through electrolysis, transforming waste material back into recoverable metal resources.
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 effectively recovers high purity valuable metals as hydroxide or metal oxides, reducing the complexity of the recovery process and improving production efficiency by avoiding the inclusion of impurities and maintaining the characteristics of the original materials.
Implementation Method 1
subjecting the scrap containing conductive oxide to electrolysis in pH-adjusted electrolyte, and thereby recovering valuable metal as hydroxide
Data Source
AI summary
Proposed is a method of recovering valuable metal from scrap containing conductive oxide including the steps of using an insoluble electrode as either an anode or a cathode, using a scrap containing conductive oxide as the counter cathode or anode, performing electrolysis while periodically inverting the polarity, and recovering the scrap as hydroxide. With the foregoing method of recovering valuable metal from scrap containing conductive oxide, oxide system scrap is conductive oxide and a substance that can be reduced to metal or suboxide with hydrogen. This method enables the efficient recovery of valuable metal from sputtering target scrap containing conductive oxide or scrap such as mill ends of conductive oxide that arise during the production of such a sputtering target.