Selective Leaching of Battery Alloy Powder for Iron Rejection
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Solution Overview
Problem
Current hydrometallurgical processes for recycling metals from Li-ion battery alloys often result in the complete dissolution of iron, leading to contamination and inefficiencies due to the use of neutralization reagents and separate downstream treatments, which complicates the separation of valuable metals like nickel, cobalt, and copper.
Innovation Solution
A process that selectively dissolves nickel and cobalt while preventing iron from being completely dissolved, using an alloyed powder with reducing properties and an oxidizing agent in a single operation, without neutralization reagents, thereby separating copper and iron and minimizing acid consumption and impurity introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrometallurgical processes dissolve iron completely from battery alloys, then iron separation is achieved, but contamination occurs and neutralization reagents are required
Solution Approach 1:
The patent changes the chemical parameters by using a controlled redox environment with specific oxidizing agents (air, oxygen, hydrogen peroxide) to maintain iron in a soluble ferrous state while selectively precipitating other metals. This parameter control allows iron to remain in solution without requiring neutralization, thus avoiding contamination from neutralization reagents while achieving effective iron separation from the alloy
2Reliability
If neutralization reagents are used to separate iron, then iron precipitation is achieved, but additional impurities are introduced
Solution Approach 1:
The patent extracts the iron separation function from the conventional neutralization process. Instead of using neutralization reagents that introduce impurities, the process extracts iron into a separate phase through controlled precipitation while maintaining other metals in solution through redox control, thus achieving iron removal without introducing additional impurities
3Reliability
If sequential Cu-cementation and Fe-precipitation steps are used, then metal separation is achieved, but process complexity increases
Solution Approach 1:
The patent merges the copper cementation and iron precipitation steps into a single simultaneous operation. By controlling the redox potential and using selective precipitants, both copper and iron are separated in one step rather than sequentially, thereby reducing process complexity while maintaining effective metal separation
4Productivity
If complete alloy dissolution is performed, then all metals are extracted, but downstream treatment requirements increase
Solution Approach 1:
The patent performs preliminary selective dissolution of specific metals (copper, nickel, cobalt) while leaving iron and other base metals in the solid residue. This preliminary action avoids the need for complete alloy dissolution and subsequent complex downstream treatment, as the valuable metals are already separated in a concentrated form ready for further processing
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 achieves high yields for nickel, cobalt, and copper dissolution while keeping iron in a solid residue, reducing downstream processing needs, and maintaining high purity of the product solution, allowing for increased metal concentrations and reduced reactor sizes.
Implementation Method 1
oxidizing with O2 and adding Na2CO3 as a neutralizing agent, resulting in a Fe-precipitate
Implementation Method 2
using an alloyed powder with reducing properties and an oxidizing agent in a single operation
Implementation Method 3
contacting, in oxidizing conditions, the alloyed powder with a stoichiometric amount of an acidic solution selected between a minimum suitable for dissolving 50% of all metallic elements except Fe
Data Source
AI summary
The invention describes a process for the separation of Fe from Cu and one or more of Ni and Co contained in an alloyed powder having more than 1% by weight of Cu, comprising the steps of: —contacting, in oxidizing conditions, the alloyed powder with a stoichiometric amount of an acidic solution selected between a minimum suitable for dissolving 50% of all metallic elements except Fe, and a maximum suitable for dissolving 100% of all metallic elements except 50% of the Fe, thereby obtaining a leach solution containing a major part of the Cu and of the one or more of Ni and Co, and a residue containing a major part of the Fe; and, —separating the leach solution from the residue. Cu, Ni and/or Co from an alloyed powder are dissolved, while the major part of Fe is rejected to a solid residue and separated by solid/liquid separation.