Lithium Hydroxide Production Through Carbonation and Thermal Conversion
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Solution Overview
Problem
Existing processes for producing lithium hydroxide from spodumene lack efficiency and environmental friendliness, particularly in achieving high purity and optimizing energy and raw material usage.
Innovation Solution
A process involving the introduction of carbon dioxide into a lithium carbonate suspension to adjust pH, allowing for the formation of more soluble lithium bicarbonate, separation of impurities, and prevention of undesirable side reactions, followed by thermal conversion and reaction with alkaline earth metal hydroxides to produce high-purity lithium hydroxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leaching processes are used to produce lithium hydroxide, then production efficiency is maintained, but product purity is insufficient for battery-grade applications
Solution Approach 1:
The process is divided into multiple sequential stages: initial leaching to extract lithium, filtration to remove insoluble impurities, carbonation to precipitate calcium carbonate, and final purification. This segmentation allows each stage to target specific impurities systematically, achieving battery-grade purity while maintaining reasonable production throughput through optimized process flow
Solution Approach 2:
Carbon dioxide is introduced as an intermediary substance to adjust pH and enable selective precipitation of calcium carbonate. This intermediary facilitates the separation of calcium impurities from lithium in the solution without requiring additional chemical reagents that would complicate the process or reduce purity
2Manufacturing precision
If traditional purification methods are applied, then some impurities are removed, but energy consumption remains high
Solution Approach 1:
The process utilizes carbonation where carbon dioxide reacts with calcium hydroxide to form calcium carbonate precipitate, which then settles and filters automatically. This self-precipitation mechanism reduces the need for energy-intensive external purification equipment and operations, achieving effective impurity removal with lower energy input
Solution Approach 2:
The pH of the leaching solution is adjusted through controlled carbonation to optimize the precipitation of calcium carbonate while keeping lithium in solution. By carefully controlling pH parameters, the process achieves selective impurity removal without requiring excessive energy for heating, cooling, or chemical treatment
3Productivity
If standard leaching conditions are used, then processing speed is maintained, but raw material utilization is suboptimal
Solution Approach 1:
The process performs preliminary leaching under optimized conditions before subsequent purification steps, ensuring maximum lithium extraction from the raw material. This preliminary action prevents loss of lithium to insoluble residues and establishes a high-concentration lithium solution that feeds efficiently into the next processing stages
Solution Approach 2:
The process maintains continuous operation where leaching, filtration, carbonation, and purification occur in an integrated flow. This continuity eliminates idle time between stages, ensures consistent raw material processing, and maximizes the utilization of input materials through uninterrupted conversion to product
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 process enhances the purity and yield of lithium hydroxide while reducing energy consumption and expanding the range of usable raw materials, ensuring high purity and efficient separation of impurities.
Implementation Method 1
introduction of carbon dioxide into a lithium carbonate suspension to adjust pH, allowing for the formation of more soluble lithium bicarbonate
Implementation Method 2
followed by thermal conversion and reaction with alkaline earth metal hydroxides
Implementation Method 3
reacting the mixture C contained in (3) with M(OH) 2 with at least partial conversion of the Li 2 CO 3 contained therein to LiOH
Implementation Method 4
Impurities that are soluble in alkaline solutions can be precipitated under these conditions and separated with the suspended analcime
Data Source
AI summary
The present invention relates to a process for producing LiOH comprising (1) providing a mixture A containing Li2CO3; (2) treating the mixture A provided in (1) with carbonic acid to at least partially convert the Li2CO3 contained therein to LiHCO3 and obtaining a mixture B containing LiHCO3; (3) thermally converting at least a portion of the mixture B obtained in (2) and obtaining a mixture C containing Li2CO3; (4) reacting the mixture C contained in (3) with M(OH)2 to at least partially convert the Li2CO3 contained therein to LiOH and obtaining a mixture D containing LiOH, where M is an alkaline earth metal.