Lithium Carbonate Purification via CO2 Dissolution and Stirring

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Solution Overview

Problem

The existing wet process for producing lithium carbonate from lithium ion battery waste results in crude lithium carbonate of low quality, requiring additional purification steps, and the reaction efficiency of carbon dioxide gas during dissolution is insufficient.

Innovation Solution

A method involving a dissolution step where crude lithium carbonate is dissolved in a liquid with carbon dioxide gas, and the liquid is stirred in a reaction vessel using a stirrer with a blade diameter to vessel diameter ratio of 0.2 to 0.5, enhancing gas reaction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If carbon dioxide gas is simply passed through the liquid in the dissolution step, then the process is simple to operate, but the reaction efficiency of carbon dioxide gas cannot be sufficiently increased

Engineering Contradiction:

Improvereaction efficiencyVSAvoidstirring device complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies dynamic stirring to transform the static gas-liquid contact process into a dynamic one. By introducing a stirrer that rotates at controlled speeds, the liquid is continuously agitated to enhance gas-liquid mixing and reaction efficiency. This dynamic approach allows optimization of reaction conditions without fundamentally changing the dissolution process architecture.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent optimizes specific parameters of the stirring system, including the rotation speed of the stirrer and the diameter ratio of the stirring blade to the reaction vessel (d/D = 0.2-0.5). By carefully controlling these parameters, the system achieves high reaction efficiency while avoiding excessive complexity. The parameter optimization ensures efficient carbon dioxide dissolution without requiring complex equipment modifications.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If crude lithium carbonate is produced by wet process, then lithium can be recovered from battery waste, but the quality of lithium carbonate is relatively low requiring additional purification

Engineering Contradiction:

Improvelithium recoveryVSAvoidlithium carbonate quality

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent performs preliminary purification actions during the dissolution step itself. By optimizing the carbon dioxide dissolution process with controlled stirring, impurities are prevented from incorporating into the lithium carbonate structure during crystal formation. This preliminary action reduces the need for subsequent purification steps while maintaining high lithium recovery from battery waste.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical purification systems with an optimized chemical dissolution process. Instead of using multiple mechanical separation and filtration stages, the invention uses controlled carbon dioxide dissolution with specific stirring parameters to achieve both high lithium recovery and high product quality in a single integrated step.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method effectively increases the gas reaction efficiency during the dissolution step, improving the quality of lithium carbonate produced and reducing the need for additional purification steps.

Implementation Method 1

the liquid is stirred in a reaction vessel using a stirrer

Methodology Applied

Scientific EffectStirring: Stirring

Implementation Method 2

dissolving the crude lithium carbonate in a liquid while feeding a carbon dioxide gas

Methodology Applied

Scientific EffectGas-liquid mixing: Turbulence

Implementation Method 3

heating a Li dissolved solution obtained in the dissolution step to release carbonic acid

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 4

heating a Li dissolved solution obtained in the dissolution step to release carbonic acid

Methodology Applied

Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 5

dissolving the crude lithium carbonate in a liquid while feeding a carbon dioxide gas

Methodology Applied

Scientific EffectGas absorption: Absorption (physical)

Data Source

PatentUS11970405B2Method for producing lithium carbonate

Publication Date: 2024.04.30 JX METALS CIRCULAR SOLUTIONS CO LTD

AI summary

Provided is a method for producing lithium carbonate from lithium ion battery waste, the lithium ion battery waste including battery positive material components containing Li and at least one metal selected from the group consisting of Co, Ni and Mn, wherein, after subjecting the lithium ion battery waste to a wet process, thereby separating the at least one metal of the battery positive material components from the lithium ion battery waste to obtain crude lithium carbonate, the method includes: a dissolution step of dissolving the crude lithium carbonate in a liquid while feeding a carbon dioxide gas; and a decarbonization step of heating a lithium dissolved solution obtained in the dissolution step to release carbonic acid, and wherein when dissolving the crude lithium carbonate in the liquid in the dissolution step, the liquid is stirred in a reaction vessel using a stirrer, and a ratio of a diameter (d) of a stirring blade of the stirrer to an inner diameter (D) of the reaction vessel (d/D) is from 0.2 to 0.5.