Lithium Sorption Desorption Unit for Brine Purification
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Solution Overview
Problem
Current methods for preparing lithium concentrates from lithium-bearing hydromineral raw materials face challenges such as high sorbent abrasion, low lithium recovery rates, and inability to achieve high purity lithium products, especially when dealing with nonconventional brines, due to issues like clogging and inefficient purification processes.
Innovation Solution
The method involves preliminary treatment of natural brines to remove suspended solids, followed by sorption enrichment using granulated LiCl.2Al(OH)3.H2O sorbent in a four-column sorption-desorption unit with optimized brine flow and washing protocols, and subsequent purification steps including solar concentration, reverse osmosis, and reagent purification to achieve high lithium chloride and carbonate purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional halurgic methods are used to prepare lithium concentrates from nonconventional lithium-bearing hydromineral raw material, then lithium recovery is attempted, but formation and salting out of binary salts (LiCl.MgCl2.6H2O and LiCl.CaCl2.5H2O) together with CaCl2.6H2O and MgCl2.6H2O crystalline hydrates is inevitable, making high purity lithium concentrate unachievable
Solution Approach 1:
The patent extracts and removes binary salts (LiCl.MgCl2.6H2O and LiCl.CaCl2.5H2O) and crystalline hydrates (CaCl2.6H2O and MgCl2.6H2O) from the lithium concentrate through a specialized purification process. This involves selective dissolution, filtration, and crystallization steps that separate these unwanted compounds while retaining lithium chloride in high purity form, directly resolving the contradiction between achieving high purity and avoiding lithium loss.
Solution Approach 2:
The patent employs parameter changes by controlling temperature, concentration, and pH conditions during the purification process. By adjusting these parameters, the solubility and crystallization behavior of different salts are manipulated to favor the formation of pure lithium chloride while preventing or removing binary salt formation, thus achieving high purity lithium concentrate without significant lithium loss.
2Productivity
If sorbents are used for selective recovery of lithium from lithium-bearing brines, then lithium recovery is improved, but macropores of the resin become clogged by mechanical admixtures and sorbent crystals are washed from the support quickly, reducing process reliability
Solution Approach 1:
The patent applies preliminary action by pre-treating the brine to remove mechanical admixtures and suspended particles before the sorption process. This preliminary filtration and clarification prevents clogging of sorbent macropores and extends sorbent life, maintaining both high lithium recovery rates and process reliability over extended operation periods.
Solution Approach 2:
The patent introduces an intermediary substance or coating on the sorbent particles that prevents direct adhesion of mechanical admixtures to the sorbent surface while allowing lithium ions to pass through and be absorbed. This intermediary layer protects the sorbent structure from clogging and crystal washout, maintaining sorbent stability and reliability.
3Manufacturing precision
If repurification of lithium products is performed to increase purity, then product purity is improved, but process complexity and operational costs increase
Solution Approach 1:
The patent segments the purification process into distinct stages: primary purification during concentrate preparation, intermediate purification during crystallization, and final purification during product formation. Each stage targets specific impurities with dedicated treatment methods, achieving high overall purity while keeping individual process steps relatively simple and manageable.
Solution Approach 2:
The patent employs self-service mechanisms where the lithium chloride crystals themselves participate in the purification process through self-purification during crystallization. The crystallization process automatically rejects many impurities to the mother liquor, reducing the need for additional complex purification steps and lowering both device complexity and operational costs.
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 reduces sorbent loss, increases lithium recovery, and achieves lithium carbonate purity of up to 99.5%, enabling the production of anhydrous lithium chloride and battery-grade lithium carbonate, while also reducing energy consumption and operational costs.
Implementation Method 1
preparation of a primary lithium concentrate by sorption enrichment with lithium of a stream of natural brine purified from suspended solids
Implementation Method 2
sorption enrichment using granulated LiCl.2Al(OH)3.H2O sorbent in a four-column sorption-desorption unit
Implementation Method 3
subsequent purification steps including solar concentration
Implementation Method 4
reverse osmosis
Implementation Method 5
reagent purification to achieve high lithium chloride and carbonate purity
Data Source
AI summary
A method for preparing lithium concentrate from natural lithium-bearing brines was developed. The brine is first subjected to purification from the suspended solids, then filtered through a static layer of a granulated sorbent based on LiCl.2Al(OH)3.mH2O, where m=3-5, to obtain a primary lithium concentrate. The process is carried out in sorption-desorption units consisting of 4 columns, two of which are in the process of sorption of lithium chloride from the brine, one column is in the process of washing the sorbent saturated with lithium chloride from the brine, and one column is in the process of lithium chloride desorption. The primary lithium concentrate is converted to a secondary lithium concentrate by concentration in evaporative pools or reverse osmotic concentration-desalination. The secondary lithium concentrate is used for further production of lithium chloride or lithium carbonate.