Cobalt Sulfate Production via Selective Impurity Removal
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Solution Overview
Problem
Current methods for producing high-purity cobalt sulfate require multiple costly processes, including electrolysis and the conversion of metallic cobalt, and do not efficiently remove impurities from cobalt chloride solutions without using electrolysis.
Innovation Solution
A method involving a copper removal step using a sulfurizing agent, a neutralization step to separate magnesium, a leaching step with sulfuric acid to obtain cobalt sulfate, and a solvent extraction step with an alkyl phosphoric acid-based extractant to remove zinc, manganese, and calcium, all without employing electrolysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolysis process is used to produce high purity cobalt sulfate, then manufacturing precision is improved, but device complexity and production cost increase
Solution Approach 1:
The invention extracts and removes impurity elements (copper, zinc, manganese, calcium, magnesium) from the cobalt chloride solution through selective precipitation and solvent extraction, obtaining high-purity cobalt sulfate without requiring electrolysis. This eliminates complex electrolytic equipment while achieving the desired purity level.
Solution Approach 2:
The invention uses simple, inexpensive chemical reagents (sulfurizing agents, oxidants, neutralizers, and solvent extractants) to achieve impurity removal, replacing expensive and complex electrolytic equipment. The chemical reagents are consumed in the process but provide a simpler overall production system.
2Manufacturing precision
If multiple purification steps are used to remove impurities from cobalt chloride solution, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The invention combines multiple impurity removal mechanisms into a unified purification sequence: copper removal by sulfurizing agent, zinc/manganese/calcium removal by oxidant and neutralizer, and magnesium removal by solvent extraction. This integrated approach achieves high purity while maintaining production efficiency through systematic process design.
Solution Approach 2:
The invention controls pH values at different stages (pH 1.5-3.0 for copper removal, pH 4.0-6.0 for zinc/manganese/calcium removal, pH 8.0-10.0 for magnesium removal) to optimize the separation efficiency of each impurity element, achieving high purity cobalt sulfate through parameter optimization rather than excessive processing steps.
3Manufacturing precision
If conventional solvent extraction method is used for impurity removal, then manufacturing precision is improved, but loss of substance increases
Solution Approach 1:
The invention uses different solvent extractants for different impurity elements: alkyl phosphoric acid for zinc, manganese, and calcium, and amine-based extractants for copper. This selective extraction approach removes impurities while minimizing cobalt loss, achieving high purity with better material conservation compared to conventional single-extractant methods.
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 directly produces high-purity cobalt sulfate by sequentially removing impurities from cobalt chloride solutions, reducing costs and eliminating the need for electrolysis, while achieving high purity and efficiency in cobalt sulfate production.
Implementation Method 1
adding a sulfurizing agent into the cobalt chloride solution and adjusting a redox potential (ORP) (based on Ag/AgCl electrodes) to 50 mV or less and a pH to 0.3 to 2.4 to obtain a copper sulfide precipitate
Implementation Method 2
adding an oxidant and a neutralizer into the copper-removed purified liquid and adjusting the redox potential (based on the Ag/AgCl electrodes) to 950 mV to 1050 mV and the pH to 2.4 to 3.0 to obtain a manganese precipitate
Implementation Method 3
bringing an organic solvent containing an alkyl phosphoric acid-based extractant to the cobalt sulfate solution and extracting zinc, manganese, and calcium into the organic solvent to separate to remove zinc, manganese, and calcium
Data Source
AI summary
Provided is a method for separating impurities and cobalt without using an electrolysis process from a cobalt chloride solution containing impurities and producing a high purity cobalt sulfate. The production method for cobalt sulfate includes: a copper removal step (S1) of adding a sulfurizing agent to a cobalt chloride solution containing one or more impurities of copper, zinc, manganese, calcium, and magnesium and generating a precipitate of sulfide of copper to separate to remove copper; a neutralization step (S2) of adding a neutralizer or a carbonation agent to a cobalt chloride solution having undergone through the copper removal step (S1) and generating cobalt hydroxide or basic cobalt carbonate to separate magnesium; a leaching step (S3) of adding sulfuric acid to the cobalt hydroxide or the basic cobalt carbonate to obtain cobalt sulfate solution; and a solvent extraction step (S4) of bringing an organic solvent containing an alkyl phosphoric acid-based extractant to the cobalt sulfate solution and extracting zinc, manganese, and calcium into the organic solvent to separate to remove zinc, manganese, and calcium. These steps are sequentially executed.