Selective Lithium Extraction via Aluminum Sorbent
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Solution Overview
Problem
Current methods for lithium recovery from aqueous solutions, such as those using packed columns or lithium-manganese oxide compositions, are inefficient and prone to contamination due to instability and mixing of loading and regeneration streams, especially when dealing with high concentrations of other alkali metal ions like sodium and potassium.
Innovation Solution
A method involving the mixing of an aluminum-containing sorbent material, such as aluminum hydroxide or aluminum oxide, with a lithium sulfate aqueous solution, followed by heating to form a selective lithium-aluminum complex, which allows for the subsequent recovery of lithium with minimal contamination from other salts, and the regeneration of the sorbent material for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packed columns are used for lithium recovery, then lithium extraction can be achieved, but the sorbent material becomes contaminated due to mixing of loading and regeneration streams
Solution Approach 1:
The process is divided into separate batch operations (loading and regeneration) performed sequentially rather than continuously, eliminating stream mixing while maintaining extraction efficiency through repeated cycles
Solution Approach 2:
The sorbent undergoes periodic cycles of loading (lithium uptake) and regeneration (lithium removal), with each cycle completing fully before the next begins, preventing contamination from simultaneous opposing flows
2Productivity
If lithium-manganese oxide compositions are used, then lithium can be recovered, but the compositions become unstable due to concentrated acid requirements
Solution Approach 1:
The regeneration condition is changed from concentrated acid to dilute acid or alternative methods, fundamentally altering the chemical environment to preserve sorbent stability while still achieving lithium removal
Solution Approach 2:
The sorbent material is designed to be stable and reusable under milder conditions, replacing the need for aggressive acid treatment that would degrade the material over time
3Productivity
If natural evaporative processes are used for lithium recovery, then lithium can be produced, but the process becomes very energy intensive
Solution Approach 1:
The process uses controlled precipitation and filtration at moderate temperatures instead of large-scale evaporation, achieving lithium separation through chemical phase changes rather than thermal evaporation of bulk solution
Solution Approach 2:
Chemical precipitation and filtration processes replace the mechanical/thermal evaporation system, using chemical reactions to selectively remove lithium at lower energy input
4Productivity
If packed columns are used with best equipment designs, then lithium extraction can proceed, but mixing of loading and regeneration streams cannot be prevented
Solution Approach 1:
Instead of attempting to prevent mixing in a continuous system, the approach is inverted by using discrete batch operations where loading and regeneration are completely separated in time, making mixing impossible
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 achieves selective lithium extraction with reduced lithium concentration in the mother liquor, maintaining high concentrations of other salts, and allows for the efficient recovery of lithium from complex mixtures, offering a cost-effective and stable process.
Implementation Method 1
mixing an excess of an aluminum-containing sorbent material into the lithium sulfate aqueous solution to form a precursor mixture
Implementation Method 2
heating the precursor mixture to a temperature of 50-200° C. to result in selective formation of a solid lithium-aluminum complex
Data Source
AI summary
A method of selectively extracting lithium from a lithium sulfate aqueous solution, the method comprising: (i) mixing an aluminum-containing sorbent material into the lithium sulfate aqueous solution to form a precursor mixture, wherein the aluminum-containing sorbent material is an aluminum hydroxide, aluminum oxide, or combination thereof; and (ii) heating the precursor mixture to a temperature of 50-200° C. to result in selective formation of a solid lithium-aluminum complex and mother liquor; and wherein the method may further comprise: (iii) recovering isolated lithium salt from the solid lithium-aluminum complex by heating the solid lithium-aluminum complex in water or aqueous solution at a temperature of 50-100° C. to result in delithiation of the solid lithium-aluminum complex with transfer of the lithium salt from the solid lithium-aluminum complex to the water or aqueous solution, along with production of aluminum hydroxide solid.