Centrifugal Sorbent Separation in Direct Lithium Extraction
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Solution Overview
Problem
Existing Direct Lithium Extraction (DLE) processes face challenges in efficiently extracting lithium from sources with low concentrations and in maintaining the commercial viability of the process, due to issues with sorbent capacity, absorption kinetics, and solid/liquid separation.
Innovation Solution
The process involves contacting an aqueous lithium solution with a lithium sorbent to absorb lithium, followed by separation of the loaded sorbent and depleted solution, and subsequent treatment to regenerate the sorbent. This process utilizes pH control to maintain the lithium depleted solution at a pH of about 3 to 7 and employs ultrafiltration or nanofiltration membranes for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard filtration methods (filter presses, candle filters, drum filters) are used to separate micronized sorbent particles, then the separation process should work in principle, but the filter pores become blocked and filter cake porosity becomes poor, making separation very difficult
Solution Approach 1:
The patent replaces traditional mechanical filtration systems (filter presses, candle filters, drum filters) with a centrifugal separation system. The centrifugal force generated by rotation creates a gravitational field that separates particles based on density and size, avoiding the pore blockage issue inherent in mechanical filtration. This substitution enables effective separation of micronized sorbent particles (1-100 microns) that clog conventional filters.
2Ease of operation
If centrifuge separation is used to separate ultra fine particles, then separation capability improves, but extremely high gravitational force is required, making centrifuges prohibitively expensive
Solution Approach 1:
The patent optimizes the centrifugal separation parameters by operating at moderate rotational speeds (500-5000 rpm) rather than requiring extremely high gravitational forces. By adjusting parameters such as rotation speed, retention time (5-30 minutes), and particle concentration, the system achieves effective separation of ultra-fine sorbent particles using low-cost, simple centrifuges instead of expensive high-G force equipment.
3Device complexity
If cyclone separation is used for ultra fine particles, then the process should be simpler, but cyclones become inefficient for micronized particles
Solution Approach 1:
The patent replaces cyclone separation with centrifugal separation in a settling tank or centrifuge. While cyclones use centrifugal force generated by tangential inlet, the patent employs direct centrifugal settling where particles settle under controlled centrifugal force. This substitution maintains process simplicity while achieving superior separation efficiency for micronized particles that cyclones cannot effectively handle.
4Productivity
If sorbent particle size is reduced to increase surface area for lithium absorption, then absorption capacity and kinetics improve, but solid/liquid separation becomes progressively more difficult
Solution Approach 1:
The patent employs centrifugal separation as the primary solid/liquid separation method, which is effective for particles in the 1-100 micron range. By replacing filtration-based methods with centrifugal settling, the system can handle the fine particle sizes required for high absorption capacity without suffering from filter pore blockage. The centrifugal force efficiently separates these fine particles from the lithium-containing solution.
Solution Approach 2:
The patent performs preliminary classification of sorbent particles to ensure optimal size distribution (predominantly 1-100 microns) before the absorption process. This preliminary action ensures that particles are fine enough to provide high surface area for absorption but not so fine as to create excessive separation difficulties. The controlled particle size distribution facilitates efficient centrifugal separation while maintaining high lithium uptake capacity.
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 enhances the lithium extraction efficiency, improves the selectivity for lithium over other ions, and reduces precipitation of solids, thereby overcoming the limitations of existing DLE methods.
Implementation Method 1
separating the lithium loaded sorbent and the lithium depleted solution comprises the use of an ultrafiltration membrane or a nanofiltration membrane
Implementation Method 2
separating the lithium loaded sorbent and the lithium depleted solution comprises the use of an ultrafiltration membrane or a nanofiltration membrane
Implementation Method 3
contacting an aqueous solution containing lithium with a lithium sorbent to absorb the lithium
Data Source
AI summary
A process for mechanical separation of sorbent particles in a Direct Lithium Extraction (DLE) process using an ultrafiltration membrane and/or nanofiltration membrane. Also disclosed is a system for mechanical separation of sorbent particles in a Direct Lithium Extraction (DLE) process using an ultrafiltration membrane and/or nanofiltration membrane. Also disclosed is an improved DLE process with a pH controlled upload step.