Lithium Hydroxide Monohydrate Crystallization via Electrochemical Cooling
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Solution Overview
Problem
Current methods for producing lithium hydroxide monohydrate are energy-intensive and require complex evaporation crystallization processes, leading to high energy consumption and investment costs.
Innovation Solution
The process involves electrochemically converting lithium salts into lithium hydroxide monohydrate by adding lithium salt to the lithium hydroxide solution emerging from the electrochemical apparatus, allowing precipitation without the need for evaporation crystallization, and regenerating the catholyte in a closed process, using cooling to manage heat and maintain constant chemical composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If evaporation crystallization is used to produce lithium hydroxide monohydrate, then high purity product is obtained, but energy consumption increases significantly
Solution Approach 1:
The invention changes the physical parameters of the system by controlling temperature and concentration to achieve crystallization without evaporation. The catholyte is cooled to below 100°C (preferably 20-80°C) and lithium salt is added to adjust concentration, causing lithium hydroxide monohydrate to crystallize directly from the concentrated solution, eliminating the need for energy-intensive evaporation while maintaining high purity
Solution Approach 2:
The invention utilizes the phase transition of lithium hydroxide from dissolved state to crystalline solid state through cooling and concentration adjustment rather than through evaporation. By controlling the temperature and adding lithium salt to the concentrated catholyte, the solution becomes supersaturated and lithium hydroxide monohydrate crystallizes directly, achieving the same purification effect as evaporation crystallization but with significantly lower energy input
2Manufacturing precision
If multi-stage evaporation crystallization is used, then lithium hydroxide monohydrate is obtained, but investment costs and process complexity increase
Solution Approach 1:
The invention merges the crystallization step with the catholyte regeneration step into a single integrated process. The concentrated catholyte is directly cooled and treated with lithium salt in the same system to produce lithium hydroxide monohydrate crystals, eliminating the need for separate evaporation equipment and multiple processing stages, thereby reducing both investment costs and process complexity while maintaining high product purity
3Productivity
If conventional electrolysis followed by evaporation is used, then lithium hydroxide is produced, but energy consumption and processing time are high
Solution Approach 1:
The invention performs preliminary concentration of the catholyte during the electrolysis process itself, so that when the catholyte exits the electrochemical apparatus, it is already at a concentration suitable for direct crystallization. This preliminary action eliminates the need for subsequent evaporation steps, significantly reducing both energy consumption and processing time while maintaining high production efficiency
Solution Approach 2:
The invention establishes a continuous process where concentrated catholyte is continuously fed to a cooling crystallization system, and lithium hydroxide monohydrate crystals are continuously separated and regenerated. This continuous operation eliminates idle time between electrolysis and crystallization steps, maintaining high productivity while reducing overall energy consumption compared to batch evaporation processes
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 the production of lithium hydroxide monohydrate with high purity and reduced energy consumption, optimizing current yields and integrating crystallization with catholyte regeneration in a closed cycle, eliminating the need for energy-intensive evaporation steps.
Implementation Method 1
The electrochemical conversion of lithium salts into lithium hydroxide is a well-known and commonly used process
Implementation Method 2
lithium hydroxide monohydrate is precipitated from an aqueous solution emerging from the electrochemical apparatus by adding the lithium salt LiaX to the aqueous solution emerging from the electrochemical apparatus
Implementation Method 3
using cooling to manage heat and maintain constant chemical composition
Data Source
AI summary
The invention relates to a method of using an aqueous solution discharged from an electrochemical apparatus for converting lithium salt dissolved in water to lithium hydroxide and the acid corresponding to the lithium salt, to produce lithium hydroxide monohydrate with simultaneous conversion of this solution to the catholyte required to enter the electrochemical apparatus. The conversion of the aqueous solution into the catholyte is preferably accomplished by a balance discharge of lithium hydroxide monohydrate as a wet product, cooling of the catholyte to remove to balance the amount of heat introduced into the catholyte with the electrochemical process, and balance refreshing of the catholyte with lithium salt in a stirred vessel. In an additional washing step, the balance of the water also reacted during the electrochemical conversion of the lithium salts used is balanced. The lithium hydroxide monohydrate product thus produced is also an object of the invention.