Lithium Hydroxide Recovery via Solid-Liquid Separation

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Solution Overview

Problem

Conventional methods for producing lithium hydroxide and sulfide solid electrolyte raw materials suffer from low recovery rates and high production costs, leading to inefficient production of sulfide solid electrolytes.

Innovation Solution

A method involving the reaction of lithium carbonate and calcium hydroxide in a controlled liquid environment, followed by solid-liquid separation, allows for efficient recovery of lithium hydroxide from the liquid component and sulfide solid electrolyte raw materials from the solid component, optimizing water usage and reducing energy costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If lithium carbonate and calcium hydroxide are reacted in water to synthesize lithium hydroxide, then lithium hydroxide can be produced, but the recovery rate of lithium component is low because lithium is removed together with solid content during solid-liquid separation

Engineering Contradiction:
Improverecovery rate of lithium componentVSAvoidlithium loss in solid content
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The invention segments the lithium-containing products into two distinct categories: lithium hydroxide in the liquid phase and lithium-containing sulfide solid electrolyte raw material in the solid phase. This segmentation allows different recovery paths for each product type, preventing lithium loss and improving overall recovery rate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the physical state parameter of lithium-containing products by controlling the reaction conditions. By adjusting the reaction parameters, lithium hydroxide remains in the liquid phase while lithium-containing sulfide forms as solid precipitate, enabling efficient separation and recovery of both products.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple similar steps are assembled to increase lithium component recovery rate, then recovery rate improves, but manufacturing equipment becomes large and complex

Engineering Contradiction:
Improverecovery rate of lithium componentVSAvoidmanufacturing equipment scale
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The solid-liquid separation step serves multiple functions simultaneously: it separates lithium hydroxide in the liquid phase for recovery, collects lithium-containing sulfide in the solid phase as raw material, and removes unreacted calcium hydroxide. This multi-functionality eliminates the need for multiple separate processing steps and reduces equipment complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of discarding the solid content as waste, the invention recovers valuable lithium-containing sulfide from the solid phase. This transforms a waste stream into a useful product, improving recovery rate without requiring additional complex equipment.

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If the amount of calcium hydroxide is increased to reduce unreacted lithium, then lithium conversion improves, but purchase cost increases due to increased lithium hydroxide usage

Engineering Contradiction:
Improveconversion efficiency of lithium carbonateVSAvoidamount of lithium hydroxide required
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The invention recovers unreacted lithium carbonate from the solid content after separation. This allows the use of excess calcium hydroxide to drive the reaction to completion without increasing costs, as the unreacted lithium carbonate is recovered and can be reused or sold.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The invention converts what would normally be considered waste (unreacted lithium carbonate in solid content) into a recoverable resource. By recovering and reusing this material, the process achieves high conversion efficiency without increasing the amount of lithium hydroxide required.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Productivity

If the amount of water is increased to improve lithium hydroxide recovery rate, then recovery rate improves, but energy cost for water removal in drying step increases

Engineering Contradiction:
Improverecovery rate of lithium hydroxideVSAvoidenergy cost for water removal
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The invention optimizes the water content parameter in the reaction system. By controlling the water amount to be sufficient for dissolution but not excessive, the process achieves high lithium hydroxide recovery rate while minimizing the energy required for subsequent drying operations.

Inventive Principle:
Principle #35Parameter changes

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 approach enables the efficient production of lithium hydroxide and sulfide solid electrolyte raw materials at lower costs, enhancing the overall production efficiency and reducing the need for extensive manufacturing equipment.

Implementation Method 1

reacting lithium carbonate with calcium hydroxide in a liquid to obtain a solution containing lithium hydroxide

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

subjecting the solution to solid-liquid separation into a liquid component containing the lithium hydroxide and a solid component containing lithium derived from the lithium carbonate

Methodology Applied
Scientific EffectSolid-liquid separation: Sedimentation

Implementation Method 3

recovering the lithium hydroxide from the liquid component

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4674813A1Method for producing lithium hydroxide, method for producing lithium-containing sulfide solid electrolyte raw material, and method for producing sulfide solid electrolyte
Publication Date: 2026.01.07 AGC INC
  • EP4674813A1 patent drawingFigure 1A
  • EP4674813A1 patent drawingFigure 1B
  • EP4674813A1 patent drawingFigure 1C

AI summary

Provided is a method for producing lithium hydroxide, the method comprising: reacting lithium carbonate and calcium hydroxide in a liquid to obtain a solution containing lithium hydroxide; subjecting the solution to solid-liquid separation into a liquid component containing the lithium hydroxide and a solid component containing lithium derived from the lithium carbonate; and recovering lithium hydroxide from the liquid component.