Black Mass Refining With Electrodialysis and Lithium Hydroxide Loop
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Solution Overview
Problem
Current lithium ion battery recycling methods are costly, environmentally impactful, and inefficient in separating and purifying nickel, cobalt, manganese, and lithium due to high CO2 emissions, sodium sulfate generation, and impurity buildup from using caustic chemicals.
Innovation Solution
A method involving leaching with sulfuric acid and a reducing agent, followed by impurity removal with lithium hydroxide, chromatographic lithium separation, ion exchange, and electrodialysis to produce lithium hydroxide and sulfuric acid in-situ, reducing the need for sodium-based chemicals and minimizing wastewater and CO2 emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrometallurgical routes use sodium or ammonium hydroxide for pH control and metal separation, then metal separation is achieved, but sodium sulfate or ammonium sulfate accumulates in process liquor requiring costly water purification
Solution Approach 1:
The patent uses lithium hydroxide for pH control and metal separation, which converts to lithium sulfate in process liquor. This lithium sulfate is then electrodialyzed to regenerate lithium hydroxide, creating a self-sustaining cycle where the system recycles its own chemicals without external inputs or waste discharge
Solution Approach 2:
The patent recovers lithium sulfate from process liquor through electrodialysis and converts it back to lithium hydroxide, which is then reused in subsequent processing steps. This closes the material loop and eliminates the need to discard chemicals or discharge waste
2Reliability
If liquid-liquid extraction uses kerosene for metal separation, then separation efficiency is improved, but kerosene fouling requires regular replacement significantly increasing CO2 output
Solution Approach 1:
The patent replaces the liquid-liquid extraction system using kerosene with an electrodialysis system that uses electric fields and ion-exchange membranes to separate and concentrate lithium. This substitution eliminates the need for organic solvents and their associated environmental problems
3Reliability
If pyrometallurgical routes use high temperatures and reducing agents for lithium recovery, then lithium extraction is achieved, but CO2 footprint increases significantly
Solution Approach 1:
The patent replaces high-temperature pyrometallurgical processing with ambient or mild temperature hydrometallurgical processing using sulfuric acid leaching followed by electrodialysis. This substitution eliminates the need for energy-intensive heating and reducing agents while achieving equivalent lithium recovery
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 achieves efficient separation and purification of nickel, cobalt, manganese, and lithium with reduced operational expenses, lower CO2 footprint, and simplified chemical handling, avoiding the need for additional downstream processing and chemical disposal.
Implementation Method 1
a mixture of electrode materials commonly referred to as black mass is often leached using a combination of an inorganic acid, e.g. sulfuric acid, and a reducing agent to dissolve the soluble elements after which the insoluble materials (e.g. graphite) can be separated by filtration
Implementation Method 2
separating lithium from the second process solution using chromatographic lithium separation producing lithium sulfate
Implementation Method 3
separating at least one of copper, nickel and cobalt from the third process solution by ion exchange
Implementation Method 4
converting the lithium sulfate produced in step 3) and/or 4) by electrodialysis to lithium hydroxide to be used in at least one of the steps 2), 3) and 4), and to sulfuric acid to be used in step 1)
Data Source
AI summary
According to an example aspect of the present invention, there is provided a method for processing a black mass to battery chemicals. The method comprises leaching the black mass using sulfuric acid and a reducing agent to produce a first process solution comprising lithium sulfate and at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate, and impurities, which first process solution is separated from graphite by filtration. Thereafter, the process comprises removing impurities from the first process solution using lithium hydroxide, to produce a second process solution, separating lithium from the second process solution using chromatographic lithium separation producing lithium sulfate and a third process solution and separating at least one of copper, nickel and cobalt from the third process solution by ion exchange producing lithium sulfate. Finally, the process comprises converting the lithium sulfate produced by electrodialysis to lithium and to sulfuric acid to be used in the method.