Rare Earth Metal Dissolution Using Copper Salt Solutions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for recovering rare earth elements from waste materials, such as pyro-metallurgical and hydrometallurgical approaches, are energy-intensive, generate significant waste, and require the use of hazardous mineral acids, making them costly and environmentally unfriendly, especially when dealing with complex materials like rare earth magnets in electronic waste.
Innovation Solution
A hydrometallurgical process using acid-free chemical dissolution with a copper (II) salt aqueous solution to dissolve rare earth metal-containing materials, allowing for the precipitation and calcination of rare earth metal oxides, sulfates, or phosphates, eliminating the need for mineral acids and reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyro-metallurgical approach is used for rare earth recovery, then metal recovery is achieved, but energy consumption increases and solid waste is generated
Solution Approach 1:
The patent changes the chemical parameters of the dissolution process by using oxidizing agents (nitric acid, hydrogen peroxide, or air oxidation) instead of traditional strong mineral acids, and controls pH levels to achieve effective rare earth dissolution with reduced energy requirements and waste generation
Solution Approach 2:
The patent introduces intermediary substances such as oxalic acid and ammonium carbonate as pH regulators and precipitation agents that enable selective separation of rare earth elements from the dissolved mixture, facilitating recovery without requiring energy-intensive pyro-metallurgical processes
2Productivity
If hydrometallurgical approach with strong mineral acids is used, then rare earth recovery rate increases, but environmental harm increases due to acid waste
Solution Approach 1:
The patent converts potentially harmful strong mineral acids into beneficial oxidizing agents (nitric acid, hydrogen peroxide, or dissolved oxygen from air) that can dissolve rare earth metals effectively while being less environmentally harmful and easier to neutralize, thereby maintaining high recovery rates while reducing environmental damage
Solution Approach 2:
The patent changes the pH control parameters from highly acidic conditions to mildly acidic or neutral conditions using oxalic acid and ammonium carbonate, which enables effective rare earth dissolution and selective precipitation without generating large volumes of hazardous acid waste
3Ease of manufacture
If pre-concentration or physical processing is performed on magnet materials, then recovery process becomes feasible, but device complexity increases
Solution Approach 1:
The patent enables the dissolution process to work effectively with shredded e-waste materials containing magnets without requiring complex pre-concentration or physical processing steps, as the oxidizing acid solution can penetrate and dissolve rare earth metals directly from the complex mixed material matrix
Solution Approach 2:
The patent creates a universal dissolution system using nitric acid combined with hydrogen peroxide or air oxidation that can handle various forms of rare earth-containing materials (magnets, alloys, e-waste) without requiring material-specific pre-processing, thereby simplifying the overall process while maintaining feasibility
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 >99% purity of rare earth metals, is time-efficient, environmentally friendly, and cost-effective, with the copper content being recoverable, thus reducing waste and capital investments, and can be easily integrated into existing processes.
Implementation Method 1
The acid-free chemical dissolution involves contacting the rare earth metal-containing material and an aqueous solution of a copper (II) salt to dissolve the material in the solution
Implementation Method 2
The dissolved rare earth metal is then precipitated from the aqueous solution as one or more rare earth metal compounds (oxalates, sulfates or phosphates)
Data Source
AI summary
A chemical dissolution method is provided for use in recycling rare earth metal-containing material such as permanent magnet material including end-of-life magnet shapes, magnet scrap and Terfenol-D alloy material by mixing the rare earth metal-containing material and an aqueous solution of a copper (II) salt to dissolve the material in the solution. The dissolved rare earth metal is then precipitated from the aqueous solution as a rare earth metal compound, such as a rare earth metal oxalate, sulfate or phosphate from which rare earth metal oxide can be obtained.