Selective Cobalt Separation via Peroxomonosulfate Precipitation
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Solution Overview
Problem
Current methods for selectively separating cobalt from solutions containing multiple metal species, such as nickel, are inefficient and pose environmental and economic risks due to the use of high pressures, costly reagents, and generation of toxic waste, especially when using oxidative precipitation with concentrated acids or chlorides.
Innovation Solution
A process involving the addition of a peroxomonosulfate salt to a solution with a pH between 1.5 and 4 to selectively precipitate cobalt as cobalt oxyhydroxide, which can be easily upgraded to cobalt oxide, using potassium peroxomonosulfate and controlling pH with bases like sodium carbonate to maintain stability and reduce effluent generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oxidative precipitation methods using concentrated acids and chlorides are used, then cobalt separation is achieved, but environmental harm and operational risks increase
Solution Approach 1:
The invention changes the chemical parameters by using peroxomonosulfate salts instead of concentrated acids and chlorides as oxidants. This substitution maintains the oxidative precipitation function while eliminating toxic harmful factors, achieving both separation efficiency and environmental safety
Solution Approach 2:
The invention employs peroxomonosulfate salts that decompose into harmless substances (sulfates and oxygen) after use, replacing persistent toxic substances like chlorides and concentrated acids. This approach eliminates long-term environmental contamination while maintaining effective cobalt separation
2Reliability
If concentrated acids are used to control pH in oxidative precipitation, then cobalt precipitation is achieved, but installation costs and operational risks increase
Solution Approach 1:
The invention replaces expensive and hazardous concentrated acids with peroxomonosulfate salts that are safer, cheaper, and decompose into harmless substances. This substitution reduces installation costs and operational risks while maintaining precipitation efficiency
Solution Approach 2:
The invention converts the harmful concentrated acid environment into a beneficial controlled pH range (1.5-4) using peroxomonosulfate salts. The salts provide the necessary oxidizing power and pH control without the harmful effects of concentrated acids, turning a hazardous process into a safer one
3Object-affected harmful factors
If peroxomonosulfate salts are used for oxidative precipitation, then environmental impact is reduced, but process complexity may increase
Solution Approach 1:
The invention simplifies the process by using peroxomonosulfate salts that directly provide both oxidation and pH control functions. This single reagent approach replaces complex acid-base titration and oxidant addition sequences, reducing operational complexity while minimizing environmental impact
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 efficient and selective cobalt extraction with reduced environmental impact, lower energy consumption, and lower costs by avoiding the use of toxic acids and chlorides, allowing for the treatment of solutions with complex matrices and low cobalt concentrations with high efficiency.
Implementation Method 1
adding a peroxomonosulfate salt to the solution to be treated, whereby the cobalt ions are selectively precipitated in the form of cobalt oxyhydroxide
Data Source
AI summary
A process for the selective separation of cobalt comprising the following successive steps: - supplying a solution to be treated containing cobalt ions and additional ions selected from metallic ions, alkali metal ions and/or rare earth ions, the solution having a pH ranging from 1.5 to 4, - adding a peroxomonosulfate salt to the solution to be treated, thereby selectively precipitating the cobalt ions in the form of cobalt oxyhydroxide.