CCAD Process for Lithium Recovery from Multivalent Salt Solutions
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Solution Overview
Problem
Existing lithium recovery processes using lithium aluminum double hydroxide (LADH) adsorbents are inefficient due to inhibition by multivalent ions like sulfate, resulting in low reversible lithium loading capacity and high operational costs.
Innovation Solution
A continuous countercurrent adsorption and desorption (CCAD) process using a lithium selective adsorbent, where a strong monovalent salt solution displaces multivalent ions, initiating a metathesis reaction to convert lithium sulfate to lithium chloride, allowing for effective deintercalation with water or dilute salt solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LADH adsorbents are used to selectively adsorb lithium ions from solutions, then lithium selectivity is improved, but multivalent ions such as sulfate anions inhibit the deintercalation of lithium ions, strongly limiting the reversible lithium loading capacity
Solution Approach 1:
The patent changes the chemical parameter of the eluant by using strong monovalent salt solutions (high ionic strength) instead of water or dilute salt solutions. This parameter change triggers a metathesis reaction that converts bound lithium sulfate to lithium chloride, enabling effective deintercalation and achieving 90-97% lithium recovery from sulfate-containing solutions.
Solution Approach 2:
The patent converts the harmful effect of multivalent ions (sulfate) that inhibit deintercalation into a beneficial process. By using strong monovalent salt solutions, the multivalent ions are displaced through metathesis reactions, and the previously inhibited deintercalation is enabled, transforming the inhibition problem into a solution mechanism.
2Ease of operation
If standard deintercalation conditions using water or dilute salt solutions are used, then the process is simple, but LADH adsorbents loaded from highly concentrated brines with multivalent anions release only about 40% to about 50% of the adsorbed lithium ions
Solution Approach 1:
The patent changes the ionic strength parameter of the eluant from dilute (standard conditions) to concentrated (strong monovalent salt solution). This parameter change enables the metathesis reaction that converts lithium sulfate to lithium chloride, dramatically improving lithium recovery from 40-50% to 90-97% while maintaining operational simplicity.
3Manufacturing precision
If chemicals such as mineral acids, organic acids, and phosphates are introduced to treat loaded adsorbent, then lithium product purity is improved, but the complexity of the lithium recovery process and operating cost are significantly increased
Solution Approach 1:
The patent extracts and removes the harmful multivalent ions (sulfate) from the system using strong monovalent salt solutions. This extraction approach achieves high-purity lithium chloride products without introducing additional chemicals like mineral acids, organic acids, or phosphates, thereby simplifying the process and reducing operating costs.
Solution Approach 2:
The patent uses inexpensive strong monovalent salt solutions (such as NaCl or KCl) as eluants instead of expensive chemicals like mineral acids, organic acids, or phosphates. These simple salt solutions effectively displace multivalent ions and enable high-purity lithium recovery at significantly lower operating costs.
4Quantity of substance
If lithium aluminum double hydroxide adsorbents are used in sulfate-containing solutions, then lithium adsorption is achieved, but the reversible lithium capacity is strongly limited due to sulfate inhibition
Solution Approach 1:
The patent changes the chemical environment parameter by using strong monovalent salt solutions as eluants. This parameter change triggers metathesis reactions that convert bound lithium sulfate to lithium chloride, enabling effective deintercalation and achieving 90-97% reversible lithium capacity from sulfate-containing solutions.
Solution Approach 2:
The patent converts the harmful sulfate inhibition effect into a beneficial process by using strong monovalent salt solutions. The sulfate ions are displaced through metathesis reactions, and the previously inhibited deintercalation is enabled, achieving high reversible lithium capacity that was previously unattainable in sulfate-containing solutions.
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
The CCAD process significantly enhances the reversible lithium capacity of LADH adsorbents, achieving lithium recovery rates of 90% to 97% from high multivalent salt solutions, with a high-purity lithium chloride product suitable for battery-grade applications.
Implementation Method 1
lithium aluminum double hydroxide (LADH) adsorbents are known to selectively adsorb lithium ions from solutions
Implementation Method 2
LADH adsorbents selectively adsorb lithium ions from solutions
Implementation Method 3
a strong monovalent salt solution displaces multivalent ions, initiating a metathesis reaction and then deintercalates the formed LiCl
Implementation Method 4
deintercalates the formed LiCl with water or a dilute salt solution
Data Source
AI summary
This invention generally relates to a process and circuit for the selective adsorption and desorption of lithium from natural and synthetic multivalent salt solutions, such as sulfate-containing solutions, using a LADH lithium selective adsorbent in a CCAD process and circuit. During the CCAD process, lithium ions load selectively and in high capacity into the LADH lithium selective adsorbent from feedstock solutions heavy in salts of both monovalent and multivalent anions. The inventive CCAD process/circuit displaces the high multivalent salt-containing feedstock solution with a strong monovalent salt solution to initiate a metathesis reaction of bound multivalent salts. The inventive process/circuit then deintercalates the formed LiCl from the LADH lithium selective adsorbent with water or a dilute salt solution.