Alkali-Halide Double Salt Preparation for Rare Earth Metal Production
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Solution Overview
Problem
Current methods for producing rare earth metals, such as metallothermic and electrolytic processes, face challenges including the use of hazardous chemicals like HF, high energy consumption, low yield, and the need for expensive and consumable electrodes.
Innovation Solution
The use of alkali-halide double salts of the form AxREyXz, where A is Li, Na, or K, and X is F, Cl, or Br, allows for the production of rare earth metals through metallothermic or electrolytic reactions without the need for HF and at room temperature, enabling both high yield and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metallothermic or electrolytic processes are used to produce rare earth metals, then production can be achieved, but hazardous chemicals like HF must be used and energy consumption is high
Solution Approach 1:
The patent converts the harmful effect of high reaction temperatures into a benefit by using the exothermic nature of the metallothermic reaction to sustain the temperature needed for slag/metal separation, eliminating the need for external heating and reducing energy consumption while avoiding hazardous chemicals
Solution Approach 2:
The patent changes the chemical composition parameters by using alkali metal fluorides (LiF, NaF, KF) as flux materials instead of traditional HF-based systems, and controls the basicity ratio (CaO/SiO2) to optimize the reaction conditions for high-yield rare earth metal production without hazardous chemicals
2Productivity
If electrolytic reduction is used, then rare earth metals can be produced, but current efficiency is low and metal recovery yield is ≤50%
Solution Approach 1:
The patent replaces the electrolytic method with a metallothermic reduction method, substituting an electrical-based system with a chemical-based system that uses exothermic reactions to reduce rare earth fluorides, achieving >90% metal recovery yield without the energy losses associated with electrolysis
3Ease of manufacture
If calcium is used for calciothermic reduction, then rare earth metals can be produced, but high temperatures are required which increases energy consumption
Solution Approach 1:
The patent changes the temperature parameter by controlling the basicity ratio (CaO/SiO2) and using alkali metal fluorides as flux materials, which modify the reaction conditions to achieve high-yield reduction at lower temperatures through optimized slag composition and exothermic reaction control
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 eliminates the use of hazardous chemicals, reduces energy consumption, and achieves high recovery yields of rare earth metals, making the process more environmentally friendly and economically viable.
Implementation Method 1
an alkali-halide double salt of the RE metal is reacted with a reductant metal to produce RE metal
Implementation Method 2
This is a typical example of the thermite reaction which, when ignited by heat (3, etc.), undergoes an exothermic redox process
Implementation Method 3
The generated slag containing CaF2 will protect the metal formed from substantial oxidation
Data Source
AI summary
Disclosed are embodiments of a method for producing a rare earth metal from a metallothermic reaction of a reductant metal and a double salt of the rare earth metal. The double salt of rare earth metal can be prepared from an alkali halide and a salt of the rare earth metal at room temperature over a time period of 2 hours of less without the requirement to use hydrofluoric acid.