Extraction system, extraction method for separating magnesium and extracting lithium from magnesium-containing brine with secondary amide-type solvent as well as applications thereof
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Solution Overview
Problem
The existing methods for extracting lithium from magnesium-containing brines, particularly those with high magnesium-lithium ratios, are inefficient and require significant acid and base consumption, leading to high costs and environmental impact.
Innovation Solution
An extraction system using secondary amide-type solvents, which are easily available and have a simple molecular structure, allows for the separation of magnesium and lithium through a process that does not require acid or base for stripping, achieving a bidirectional equilibrium between extraction and stripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional extractants (TBP, ionic liquids, sulfonamides) are used for lithium extraction from magnesium-containing brines, then lithium extraction capability is improved, but acid and base consumption increases and equipment corrosion worsens
Solution Approach 1:
The patent changes the chemical parameters of the extractant by using secondary amide compounds with specific molecular structures (Formula I) instead of conventional extractants. This parameter change in extractant chemistry enables effective lithium extraction without requiring acid or base for stripping, thus reducing acid and base consumption while maintaining high lithium extraction capability
Solution Approach 2:
The patent employs composite extractant systems combining secondary amide compounds with specific physical and chemical properties. These composite material systems achieve both high lithium extraction efficiency and compatibility with water stripping, eliminating the need for corrosive acids and bases in the stripping process
2Productivity
If conventional extractant systems are used, then lithium extraction is achieved, but process complexity increases due to multiple steps requiring acid and base
Solution Approach 1:
The patent extracts and eliminates the unnecessary acid and base steps from the conventional extraction process. By using secondary amide extractants that can be stripped with water alone, the process removes the complex acidification and neutralization steps, significantly simplifying the overall process while maintaining effective lithium extraction
Solution Approach 2:
Instead of using acid to strip lithium from the organic phase as in conventional methods, the patent inverts the approach by using water to strip lithium. This inversion is made possible by the unique properties of secondary amide extractants, which form complexes that are soluble in water but not in organic solvents, thereby simplifying the stripping step
3Productivity
If conventional extractants are used for separation, then lithium can be extracted, but separation coefficient between lithium and magnesium decreases
Solution Approach 1:
The patent applies local quality by designing extractant molecules with specific functional groups and structural characteristics (Formula I) that create selective interaction zones. The secondary amide group with specific R1 and R2 substituents creates a local chemical environment that preferentially binds lithium ions while excluding magnesium ions, achieving high separation coefficients
Solution Approach 2:
The secondary amide extractant acts as an intermediary substance that facilitates selective lithium-magnesium separation. The extractant forms stable complexes with lithium ions in the brine, enabling selective extraction and achieving high separation coefficients between lithium and magnesium
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 significantly reduces acid and base consumption, simplifies the extraction and separation process, and achieves high separation coefficients for lithium and magnesium, making it economically viable and environmentally friendly.
Implementation Method 1
an extraction system and an extraction method for separating magnesium and extracting lithium from magnesium-containing brine through solvent extraction
Data Source
AI summary
The secondary amide contained in the extraction system consists of a single compound or a mixture of two or more compounds, wherein R1 is selected from a C2˜C12 alkyl, or a C3˜C12 cycloalkyl containing a single-ring structure, R2 is selected from a C1˜C11 alkyl, or a C3˜C11 cycloalkyl containing a single-ring structure; the total number of carbon atoms in the molecule is 12˜18. With a volume ratio of an organic phase and a brine phase being 1˜10:1, at a brine density of 1.25˜1.38 g/cm3 and at a temperature of 0˜50° C., a single-stage or multi-stage countercurrent extraction and a stripping are conducted to obtain a water phase with a low magnesium-lithium ratio, which is subjected to concentration, impurity removal and preparation to get lithium chloride, lithium carbonate and lithium hydroxide respectively. Water is used for stripping, greatly reducing the consumption of acid and base, and the separation process is shortened.