High Purity Cobalt Chloride via pH-Controlled Electrolysis
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Solution Overview
Problem
Conventional methods for producing high purity cobalt chloride result in low purity levels and inefficient production, with impurities like alkali metals, gas components, and sulfur affecting the quality and durability of magnetic materials and semiconductor devices.
Innovation Solution
A method involving electrolysis using a cobalt anode with 5N purity, a hydrochloric acid bath at pH 1.5 to 3.0, and an anion exchange membrane to inhibit impurity deposition, along with electrosynthesis and controlled acid concentration adjustment, and subsequent evaporation and filtration to achieve high purity cobalt chloride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cobalt is electrolyzed using conventional methods with diluted hydrochloric acid at pH 1, then cobalt chloride is produced, but cobalt becomes electrodeposited onto the cathode plate resulting in low production efficiency
Solution Approach 1:
The patent changes the pH parameter of the electrolytic solution from conventional pH 1 to pH 2.0 or higher, which fundamentally alters the electrodeposition behavior of cobalt. At this elevated pH level, cobalt remains in solution as Co2+ ions rather than being reduced and deposited on the cathode, thereby preventing cobalt loss and improving production efficiency while maintaining effective cobalt chloride production
2Manufacturing precision
If conventional electrolysis is used with pH 1 hydrochloric acid, then cobalt chloride is produced, but the achieved purity level is only 2N5 (99.5 wt %) which is insufficient for high purity applications
Solution Approach 1:
The patent employs parameter changes by elevating the pH to 2.0 or higher and controlling the potential difference between electrodes to 1.5V or less, which selectively prevents impurity deposition while maintaining cobalt dissolution. This achieves 5N (99.999%) or higher purity levels without requiring complex additional purification steps, thereby improving manufacturing precision while keeping the process simple
3Reliability
If high purity cobalt chloride is produced for semiconductor CVD materials, then impurity elimination is required, but conventional methods cannot achieve sufficient purity to eliminate harmful effects of impurities
Solution Approach 1:
The patent applies parameter changes by controlling pH at 2.0 or higher and potential difference at 1.5V or less during electrolysis, which creates optimal conditions for selective cobalt dissolution while preventing co-deposition of impurities. This achieves 5N or higher purity levels that reliably eliminate harmful impurity effects in semiconductor applications
Solution Approach 2:
The patent uses an ion-exchange membrane as an intermediary between the anode and cathode compartments. This membrane selectively transports ions while blocking particulate impurities and preventing cross-contamination, thereby enhancing the reliability of the produced cobalt chloride for high-purity semiconductor applications
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 achieves high purity cobalt chloride with impurity levels below 1 ppm, suitable for semiconductor CVD materials, improving production efficiency and reducing costs while maintaining high volume production.
Implementation Method 1
the cobalt anode and a cathode plate are partitioned with an anion exchange membrane
Implementation Method 2
a diluted hydrochloric acid bath having a pH of 1.5 to 3.0 is used as an electrolytic solution
Implementation Method 3
electrolytically dissolving the cobalt anode
Implementation Method 4
using a diluted hydrochloric acid bath having a pH of 1.5 to 3.0 as an electrolytic solution
Data Source
AI summary
Provided is high purity cobalt chloride having a purity of 5N (99.999%) or higher, and a manufacturing method of the high purity cobalt chloride via electrolysis, wherein cobalt having a purity of 5N or higher is used as an anode, a diluted hydrochloric acid bath having a pH of 1.5 to 3.0 is used as an electrolytic solution, the cobalt anode and a cathode plate are partitioned with an anion exchange membrane, and electrodeposition of the cobalt onto the cathode plate is thereby inhibited. An object of this invention is to provide a manufacturing method capable of providing high purity cobalt chloride at a higher purity and at a lower production cost than conventional methods. Under circumstances where demands for cobalt chloride may increase, cobalt chloride needs to be manufactured at high volume and at low cost, and the present invention offers a technique capable of satisfying the foregoing requirements.