Anhydrous Lithium Hydroxide Dehydration via High-Temperature Gas Flow
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Solution Overview
Problem
Existing methods for producing anhydrous lithium hydroxide face challenges such as high water content variability in lithium hydroxide hydrates, leading to inaccurate lithium metering and the introduction of impurities due to corrosive properties, and inefficiencies in dehydration processes like vacuum batch processes and rotary kiln methods.
Innovation Solution
A process involving the removal of water from particulate lithium hydroxide hydrate by exposing it to a gas stream with temperatures between 150°C to 500°C for 0.5 to 20 seconds, using a preferred temperature range of 300 to 450°C, and a residence time of 0.5 to 10 seconds, which can be conducted in a fluidized bed or tubular reactor, utilizing pre-treated gases with controlled CO2 content to minimize lithium carbonate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vacuum batch process is used for dehydration, then water removal is achieved, but residence time is too long (at least two hours) which limits space velocity and productivity
Solution Approach 1:
The invention changes the temperature parameter from ambient (vacuum batch process) to elevated temperatures (150-500°C), and changes the process mode from batch to continuous flow, achieving rapid dehydration within 0.5-20 seconds while maintaining high water removal efficiency
Solution Approach 2:
The invention implements a continuous flow process where LiOH hydrate particles are continuously conveyed through a heated zone by a gas stream, eliminating the batch processing time limitation and enabling high space velocity while maintaining effective dehydration
2Quantity of substance
If rotary kiln process is used for dehydration, then water removal is achieved, but strong abrasion occurs due to corrosive properties of LiOH leading to impurities
Solution Approach 1:
The invention uses a gas stream to pneumatically convey LiOH hydrate particles through the dehydration zone, eliminating mechanical contact and abrasion that occurs in rotary kilns, thus preventing impurity generation while maintaining effective water removal
Solution Approach 2:
The invention replaces the mechanical tumbling and grinding action of a rotary kiln with a pneumatic flow system, substituting mechanical stress with thermal energy for dehydration, thereby avoiding mechanical impurities
3Quantity of substance
If LiOH hydrate is used for lithium source, then lithium content is reduced (only 38% by weight), but water content varies due to aging and hygroscopicity leading to inaccurate lithium metering
Solution Approach 1:
The invention performs preliminary dehydration of LiOH hydrate to produce anhydrous LiOH before use as lithium source, eliminating the variability in water content that causes metering inaccuracies, while maintaining the advantage of higher lithium content compared to Li2CO3
4Productivity
If high temperature is used for dehydration, then water removal efficiency increases, but temperature should not exceed 453°C to avoid melting and clogging
Solution Approach 1:
The invention uses a dynamic residence time control where particles are quickly conveyed through the high-temperature zone (150-500°C) with residence times of 0.5-20 seconds, achieving rapid dehydration while limiting total exposure time to prevent melting and clogging
Solution Approach 2:
The invention implements a rapid pass-through process where LiOH hydrate particles are quickly heated and dehydrated in a short residence time window, skipping through the temperature danger zone before melting can occur, thus achieving high dehydration rates without exceeding safe temperature limits
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 produces anhydrous lithium hydroxide with minimal residual water content, ensuring accurate lithium metering and avoiding impurities, while maintaining a high lithium yield and reducing the risk of gas formation during calcination.
Implementation Method 1
removing water from particulate LiOH hydrate by subjecting said LiOH hydrate to a stream of gas with a temperature in the range of from 150 to 500°C
Implementation Method 2
subjecting said LiOH hydrate to a stream of gas with a temperature in the range of from 150 to 500°C
Data Source
AI summary
Process for making anhydrous lithium hydroxide, said process comprising the step of removing water from particulate LiOH hydrate by subjecting said LiOH hydrate to a stream of gas with a temperature in the range of from 150 to 500°C wherein the average residence time of the LiOH is in the range of from 0.5 to 20 seconds.