Lithium Carbonate Electrolysis With Lithium Recovery Loop
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Solution Overview
Problem
Existing processes for producing high purity lithium hydroxide and lithium carbonate are energy intensive, result in significant lithium losses, and rely on solar evaporation of low-concentration lithium brines, which is environmentally detrimental and inefficient.
Innovation Solution
A process involving the reaction of lithium carbonate with hydrochloric acid to form lithium chloride brine, followed by pH adjustment, electrolysis, and recycling of depleted anolyte or spent liquor to form lithium carbonate, which is then used as a starting material or base for impurity precipitation, utilizing internally generated carbon dioxide to avoid external sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solar evaporation ponds are used to concentrate lithium brines, then lithium concentration is increased, but environmental damage occurs and groundwater is lost
Solution Approach 1:
The patent replaces the mechanical solar evaporation process with an electrochemical electrolysis process. Instead of using solar energy and evaporation ponds to concentrate lithium brines, the invention uses an electrolyser to directly process the brine and produce high purity lithium hydroxide through electrochemical reactions, thereby eliminating environmental damage associated with solar evaporation
Solution Approach 2:
The patent changes the concentration parameter by using electrolysis to directly produce high purity lithium hydroxide (99.5% or higher) from lithium chloride brines, eliminating the need for intermediate concentration steps through solar evaporation. The electrolysis process achieves both concentration and purification in one step
2Manufacturing precision
If electrochemical processes are used to obtain lithium hydroxide and lithium carbonate, then high purity products are produced, but lithium losses occur
Solution Approach 1:
The patent recovers lithium from the anolyte stream that would otherwise be discarded. The anolyte, which contains lithium chloride after electrolysis, is reacted with sodium carbonate to precipitate lithium carbonate, which is then filtered and dried. This recovered lithium carbonate can be reused as a starting material or sold as a product, thereby minimizing lithium losses
Solution Approach 2:
The patent implements a feedback loop where the anolyte from the electrolysis process is fed back into the system through reaction with sodium carbonate to produce lithium carbonate. This closed-loop approach ensures that lithium is continuously recovered and reused, minimizing losses while maintaining high product purity
3Quantity of substance
If low concentration lithium brines are processed, then natural resources are utilized, but energy consumption increases and lithium losses occur
Solution Approach 1:
The patent maintains continuous operation of the electrolysis process, with continuous feed of lithium chloride brine and continuous production of lithium hydroxide. The anolyte is continuously reacted with sodium carbonate to recover lithium carbonate, which can be fed back into the system. This continuous operation improves energy efficiency by avoiding repeated heating and cooling cycles
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
Minimizes lithium losses to below 5% and eliminates the need for solar evaporation, achieving high purity lithium hydroxide and lithium carbonate production efficiently and sustainably.
Implementation Method 1
reacting lithium carbonate with hydrochloric acid to form a lithium chloride brine and carbon dioxide
Implementation Method 2
electrolysing the brine in an electrolyser
Implementation Method 3
a membrane effective at preventing boron and sulfate impurities from passing from the anolyte to the catholyte
Implementation Method 4
isolating lithium hydroxide by crystallisation from the catholyte
Implementation Method 5
adding carbon dioxide to the catholyte that is removed from the electrolyser to form lithium carbonate
Implementation Method 6
adding a base to said brine to increase the pH of the brine and cause precipitation of divalent impurities
Data Source
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AI summary
Electrolytic processes are provided for the conversion of lithium carbonate to high purity lithium hydroxide or higher purity lithium carbonate, which involve steps that recycle lithium after electrolysis in order to reduce lithium losses and increase the efficiency of the processes.