Electrochemical Lithium Hydroxide Production with Impurity Removal

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Solution Overview

Problem

The existing methods for producing lithium hydroxide face challenges in achieving high purity with low impurity levels, particularly sodium, calcium, and chlorides, leading to increased time and cost due to the need for additional purification steps, and the use of natural brines results in high magnesium concentrations making lithium recovery uneconomical.

Innovation Solution

A process involving electrolysis or electrodialysis of an aqueous lithium compound composition, maintaining a pH of 1 to 4, followed by leaching, precipitation, and ion exchange to convert lithium compounds into lithium hydroxide, reducing metal ion content and achieving high purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If natural brines are used as starting material, then lithium recovery can be performed, but high magnesium concentrations make the process uneconomical and additional purification steps are required to achieve low impurity levels

Engineering Contradiction:

Improvelithium recoveryVSAvoidmanufacturing cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent extracts and removes magnesium ions from the brine solution using selective precipitation agents (such as sodium carbonate or hydroxide) before the electrolysis process. This extraction step separates the harmful magnesium impurity from the lithium-containing solution, allowing economical lithium recovery without carrying forward the magnesium contamination that would otherwise make the process uneconomical.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary purification steps (precipitation and filtration) before the main electrolysis process to remove magnesium and other impurities from the brine. By conducting these purification actions in advance, the subsequent electrolysis operates on a cleaner feed solution, reducing energy consumption and improving overall process economics while still achieving high lithium recovery.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If additional purification steps are performed to achieve low impurity levels, then high purity lithium hydroxide can be produced, but production time and cost increase

Engineering Contradiction:

ImprovepurityVSAvoidproduction time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent combines multiple purification functions into a single integrated electrolysis cell design. The cell incorporates both product formation (lithium hydroxide generation at the cathode) and impurity removal (magnesium precipitation and filtration) within one continuous process unit. This merging of functions achieves high purity lithium hydroxide production without requiring separate, time-consuming purification stages.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a continuous electrolysis process where brine feed is continuously processed through the electrolysis cell, with continuous monitoring and adjustment of pH and impurity levels. The useful action of lithium hydroxide production continues uninterrupted while purification occurs simultaneously within the same process stream, eliminating batch processing delays and reducing overall production time while maintaining high purity standards.

Inventive Principle:

Principle #20Continuity of useful action

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 effectively produces high-purity lithium hydroxide by minimizing impurities, optimizing yield, and reducing production time and costs, addressing the limitations of current methods.

Implementation Method 1

submitting an aqueous composition comprising a lithium compound to an electrolysis or an electrodialysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

submitting an aqueous composition comprising a lithium compound to an electrolysis or an electrodialysis

Methodology Applied

Scientific EffectElectrodialysis:

Implementation Method 3

reacting the aqueous composition comprising Li+ and the at least one metal ion with a base so as to obtain a pH of about 4.5 to about 6.5 and thereby at least partially precipitating the at least one metal ion under the form of at least one hydroxide

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Implementation Method 4

contacting the aqueous composition comprising Li+ and having a reduced content of the at least one metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from the composition

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentUS12410531B2Processes for preparing lithium hydroxide

Publication Date: 2025.09.09 NEMASKA LITHIUM

AI summary

There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.