Selective Cobalt Stabilization in Nickel Leaching
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Solution Overview
Problem
Current methods for recovering nickel from nickel-containing ores are energy-intensive, inefficient, and sensitive to impurities, and fail to effectively separate nickel from cobalt in mixed hydroxide precipitates, which are valuable intermediates in nickel and cobalt refining.
Innovation Solution
A method involving the use of an acidic leach solution with an oxidizing agent, such as persulphates or permanganates, to selectively stabilize cobalt in the solid phase while dissolving nickel, allowing for efficient separation and recovery of nickel from mixed nickel-cobalt hydroxide precipitates through electrowinning or crystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional acid leaching followed by mixed hydroxide precipitation is used, then nickel and cobalt can be concentrated into MHP, but nickel and cobalt cannot be effectively separated and require complex multi-stage processing
Solution Approach 1:
The invention changes the chemical parameters of the leaching solution by adding oxidizing agents (such as hydrogen peroxide, sodium peroxide, or ozone) to create a highly oxidizing acidic environment. This parameter change causes cobalt to be oxidized to cobalt(III) which precipitates as cobalt oxyhydroxide, while nickel remains in solution as nickel(II) ions, achieving effective separation in a single stage process
Solution Approach 2:
The invention extracts cobalt from the mixed hydroxide precipitate by selective oxidation and precipitation. The oxidizing agent selectively oxidizes cobalt(II) to cobalt(III) which then precipitates as cobalt oxyhydroxide, separating it from nickel that remains in the leach solution. This extraction principle simplifies the separation process from multiple stages to a single selective precipitation step
2Manufacturing precision
If ammonia/ammonium carbonate leaching with solvent extraction is used, then nickel can be separated from cobalt, but the process becomes energy intensive and requires excessive processing stages
Solution Approach 1:
The invention replaces the mechanical solvent extraction system with a chemical precipitation system. Instead of using organic solvents and multiple extraction stages, the process uses oxidizing agents to chemically precipitate cobalt as cobalt oxyhydroxide, which is then filtered. This substitution eliminates the need for energy-intensive solvent extraction equipment and reduces the number of processing stages while maintaining high separation efficiency
3Productivity
If mixed hydroxide precipitate is added to iron smelter melt, then nickel can be alloyed with iron, but cobalt is not recovered and is lost
Solution Approach 1:
The invention extracts cobalt from the mixed hydroxide precipitate before the nickel smelting process by selective oxidation and precipitation. The oxidizing agent selectively oxidizes cobalt(II) to cobalt(III) which precipitates as cobalt oxyhydroxide, separating it from nickel that remains in solution. This extraction ensures cobalt is recovered and can be processed separately, preventing loss in the iron smelter melt while maintaining efficient nickel recovery
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 enables a straightforward, energy-efficient separation of nickel from cobalt, achieving high nickel recovery and stabilization of cobalt and manganese in the solid phase, simplifying the processing of mixed hydroxide precipitates and reducing the need for multiple processing stages.
Implementation Method 1
contacting the ore or ore processing intermediate with an acidic leach solution comprising an oxidizing agent, the oxidizing agent present in an amount sufficient to stabilise a major portion of the cobalt in the solid phase while a major portion of the nickel is dissolved
Implementation Method 2
a method of recovering a metal from a source material... selectively recovering a metal directly from a solid ore or ore processing intermediate containing said metal and cobalt
Data Source
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AI summary
A method of selectively leaching a metal such as nickel from an ore or ore processing intermediate comprising the metal and cobalt. The ore or ore processing intermediate is contacted with an acidic leach solution comprising an amount of an oxidising agent sufficient to oxidise a major portion of the cobalt to thereby cause it to be stabilised in the solid phase while a major portion of the metal is dissolved for subsequent recovery.