Rare-Earth Separation via Solubility Difference and Chelating Agents
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Solution Overview
Problem
Existing methods for separating and recovering rare-earth elements from compositions containing multiple kinds of rare-earth elements often use harsh chemicals, leading to environmental concerns and low separation rates, which are inefficient and unsustainable.
Innovation Solution
A method involving the introduction of a mixture containing rare-earth oxychlorides and chlorides into a liquid, where the difference in solubility allows for the separation and recovery of specific rare-earth elements as insoluble matters or dissolved species, using a process that minimizes environmental impact and enhances separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong acids at extremely high concentration and solvents of high volatility are used for separating and recovering rare-earth elements, then the separation process can be performed, but considerable environmental effects are caused
Solution Approach 1:
The invention changes the chemical parameters of the separation process by using mild acids (hydrochloric acid at 0.1-6 mol/L or sulfuric acid at 0.05-3 mol/L) instead of strong acids at extremely high concentration. This parameter change maintains separation capability while significantly reducing environmental harm from harsh chemicals
Solution Approach 2:
The invention converts the previously harmful use of strong acids and volatile solvents into a beneficial process by employing environmentally friendly mild acids and water-soluble chelating agents, thereby eliminating the harmful effects while achieving the same separation objective
2Productivity
If conventional separation methods are used, then separation can be performed, but the separation rate of rare-earths is low
Solution Approach 1:
The invention introduces water-soluble chelating agents (EDTA, DTPA, or HIDA) as intermediaries to facilitate the separation process. These chelating agents form stable complexes with rare-earth elements, enabling high separation rates through selective complexation and precipitation reactions
Solution Approach 2:
The invention optimizes separation parameters including acid concentration (0.1-6 mol/L for HCl, 0.05-3 mol/L for H2SO4), chelating agent concentration (0.1-6 mol/L), temperature (20-100°C), and pH control to achieve maximum separation rate and efficiency
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 effectively separates and recovers rare-earth elements with a high separation rate while reducing environmental effects, enabling the reuse of rare-earth elements from wastes and promoting sustainable resource management.
Implementation Method 1
a step of introducing, into a liquid, a mixture containing a rare-earth oxychloride and a rare-earth chloride, the rare-earth oxychloride constituted from a rare-earth element different from a rare-earth element constituting the rare-earth chloride, thereby obtaining an insoluble matter containing the rare-earth oxychloride and a liquid in which the rare-earth chloride is dissolved
Data Source
AI summary
A method for separating and recovering a plurality of rare-earth elements, the method including a step of introducing, into a liquid, a mixture containing a rare-earth oxychloride and a rare-earth chloride, the rare-earth oxychloride constituted from a rare-earth element different from a rare-earth element constituting the rare-earth chloride, thereby obtaining an insoluble matter containing the rare-earth oxychloride and a liquid in which the rare-earth chloride is dissolved, a step of recovering the rare-earth oxychloride from the insoluble matter, and a step of recovering the rare-earth chloride from the liquid in which the rare-earth chloride is dissolved.