Lithium Metal Production via Closed-Loop Chlorination and Electrolysis
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Solution Overview
Problem
Current methods for producing lithium metal through molten salt electrolysis face challenges such as corrosion from chlorine gas and molten lithium carbonate, anode consumption, and difficulties in controlling carbonate concentration, leading to inefficiencies and safety concerns.
Innovation Solution
A method involving the reaction of lithium carbonate with chlorine gas in a dry process to produce anhydrous lithium chloride, which is then used in molten salt electrolysis, with the generated chlorine gas reused to continuously produce anhydrous lithium chloride, avoiding external discharge and utilizing inexpensive lithium carbonate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium carbonate is used as a lithium source in molten salt electrolysis, then production cost is reduced, but the graphite anode is consumed and lithium metal reacts with lithium carbonate to obstruct continuous electrolysis
Solution Approach 1:
The harmful reaction between lithium metal and lithium carbonate is eliminated by extracting/removing lithium carbonate from the electrolyte system. The patent uses anhydrous lithium chloride as the electrolyte instead of lithium carbonate, preventing the side reaction while maintaining continuous electrolysis capability.
Solution Approach 2:
The patent changes the chemical composition parameter of the electrolyte from lithium carbonate to anhydrous lithium chloride. This parameter change eliminates the harmful reaction while preserving the electrolysis function, allowing continuous operation with graphite anode.
2Manufacturing precision
If anhydrous lithium chloride is produced by conventional methods, then high purity product is obtained, but additional costs for dehydrating and drying operations are required
Solution Approach 1:
The patent converts the harmful chlorine gas byproduct from electrolysis into a useful resource for producing anhydrous lithium chloride through reaction with lithium hydroxide. This eliminates the need for separate dehydration and drying operations while maintaining high purity product.
Solution Approach 2:
The patent merges the electrolysis process with the lithium chloride production process by using the generated chlorine gas in-situ to convert lithium hydroxide into anhydrous lithium chloride. This combines multiple operations into one integrated system.
3Manufacturing precision
If lithium hydroxide is used as a raw material for producing anhydrous lithium chloride, then anhydrous product is obtained, but handling difficulties and additional safety costs arise due to strong alkalinity
Solution Approach 1:
The patent uses chlorine gas as an intermediary substance to convert lithium hydroxide into anhydrous lithium chloride. This intermediary approach allows the transformation to occur in a controlled manner without direct handling of the strongly alkaline lithium hydroxide in its reactive state.
4Temperature
If molten lithium carbonate is used for producing anhydrous lithium chloride, then reaction proceeds at high temperature, but severe corrosion occurs to metal materials requiring ceramic or special materials
Solution Approach 1:
The patent changes the physical state parameter of lithium carbonate from molten to solid form in the chlorination reaction. This parameter change allows the reaction to proceed at lower temperatures with reduced corrosion, enabling the use of conventional metal materials for the reaction vessel.
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 enables efficient and safe production of lithium metal by preventing corrosion, reducing anode consumption, and maintaining high current efficiency, while forming a closed system that minimizes environmental impact and operational costs.
Implementation Method 1
contacting and reacting lithium carbonate and chlorine gas in a dry process to produce anhydrous lithium chloride
Implementation Method 2
subjecting a raw material for electrolysis comprising said anhydrous lithium chloride obtained from step (A) to molten salt electrolysis under such conditions as to produce lithium metal
Data Source
AI summary
Provided is a safe and efficient method for producing lithium metal which facilitates efficient production of anhydrous lithium chloride without corrosion of the system materials by chlorine gas or molten lithium carbonate, and which allows production of lithium metal by molten salt electrolysis of the produced anhydrous lithium chloride as a raw material. The method includes the steps of (A) contacting and reacting lithium carbonate and chlorine gas in a dry process to produce anhydrous lithium chloride, and (B) subjecting the raw material for electrolysis containing the anhydrous lithium chloride to molten salt electrolysis under such conditions as to produce lithium metal, wherein the chlorine gas generated by the molten salt electrolysis in step (B) is used as the chlorine gas in step (A) to continuously perform steps (A) and (B).