Lithium Hydroxide Production Through Carbonation and Impurity Separation
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Solution Overview
Problem
Existing processes for producing lithium hydroxide from spodumene lack efficiency and purity, particularly in terms of continuous production of high-purity lithium hydroxide and optimization of energy and raw material use, which is crucial for producing powerful and long-lasting batteries.
Innovation Solution
A process involving the introduction of carbon dioxide into a lithium carbonate suspension to adjust the pH from 10-11 to 7.5, forming more soluble lithium bicarbonate, allowing for efficient separation of impurities and eliminating the need for thermal decomposition of lithium bicarbonate, thereby enhancing purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium carbonate is treated with strong alkali for leaching, then lithium extraction efficiency is improved, but impurity co-extraction increases and product purity deteriorates
Solution Approach 1:
The patent changes the pH parameter from highly alkaline (pH 10-11) to near-neutral (pH 7.3-7.7) by introducing CO2. This parameter change allows lithium to be extracted at near-neutral pH without significant co-extraction of impurities, resolving the contradiction between extraction efficiency and product purity
Solution Approach 2:
The patent performs preliminary carbonation of lithium carbonate to form lithium bicarbonate before the leaching step. This preliminary action creates a near-neutral pH environment that enables selective lithium extraction while preventing impurity co-extraction, thus improving both extraction efficiency and product purity
2Manufacturing precision
If thermal decomposition of lithium bicarbonate is performed, then lithium carbonate is obtained, but energy consumption increases and CO2 emissions rise
Solution Approach 1:
The patent converts the harmful effect of CO2 emissions from thermal decomposition into a beneficial process by using CO2 to carbonate lithium carbonate to lithium bicarbonate. This eliminates the need for thermal decomposition, reducing energy consumption while maintaining product quality
Solution Approach 2:
The patent uses a chemical phase transition (carbonation) instead of thermal decomposition. By converting lithium carbonate to lithium bicarbonate through CO2 treatment, the process avoids high-temperature heating and subsequent decomposition, thereby reducing energy consumption and CO2 emissions
3Manufacturing precision
If multiple leaching and purification steps are used, then product purity is improved, but process complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and removes impurities at the near-neutral pH stage before final lithium hydroxide production. By performing impurity removal at this optimal pH condition, the process achieves high purity with fewer subsequent purification steps, reducing overall process complexity
Solution Approach 2:
The patent performs preliminary pH adjustment and impurity removal before the main lithium hydroxide production step. This preliminary action simplifies the overall process by preventing impurity co-extraction in the first place, eliminating the need for multiple complex purification steps
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 process achieves high-purity lithium hydroxide production with improved separation of impurities and reduced carbon dioxide emissions, expanding the range of usable raw materials and optimizing energy and raw material usage.
Implementation Method 1
introduction of carbon dioxide into a lithium carbonate suspension to adjust the pH from 10-11 to 7.5
Implementation Method 2
forming more soluble lithium bicarbonate
Implementation Method 3
reacting the mixture B obtained in (2) with M(OH)2 to at least partially convert the LiHCO3 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) reacting the mixture B obtained in (2) with M(OH)2 to at least partially convert the LiHCO3 contained therein to LiOH and obtaining a mixture C containing LiOH, where M is an alkaline earth metal.