Black Mass Leaching Sequence for Lower-Cost Li-Ion Metal Recovery
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Solution Overview
Problem
Current lithium-ion battery recycling processes face challenges such as high energy consumption, costly reagents, and complex separation steps, particularly in hydrometallurgical methods, which lead to inefficient recovery of valuable metals like Ni, Mn, and Co, and result in significant waste generation and high capital expenditures.
Innovation Solution
A two-stage leaching process is employed, where acid leaching is followed by reductive leaching with H2O2, and a Li basic solution is used in upstream processes to minimize reagent consumption, reduce impurity co-precipitation, and eliminate unnecessary separation steps, thereby enhancing the recovery of Ni, Mn, and Li while minimizing capital and reagent costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional hydrometallurgical processes are used with single-stage leaching, then metals can be recovered from black mass, but H2O2 consumption is high and leaching efficiency is reduced due to decomposition at elevated temperatures
Solution Approach 1:
The leaching process is divided into two distinct stages: Stage 1 uses only H2SO4 at elevated temperature (70-90°C) for initial metal dissolution, while Stage 2 uses H2SO4 + H2O2 at lower temperature (40-60°C) for complete leaching. This segmentation allows each stage to operate under optimal conditions, preventing H2O2 decomposition that would occur if it were added in the first stage, thereby reducing H2O2 consumption while maintaining high metal recovery quantities.
2Quantity of substance
If pyrometallurgical processes are used for black mass processing, then metals can be recovered, but energy consumption is high and toxic gas treatment is required
Solution Approach 1:
The patent replaces the pyrometallurgical mechanical/thermal system with a hydrometallurgical chemical system. Instead of using high-temperature smelting (pyrometallurgy), the invention uses controlled chemical leaching with H2SO4 and H2O2 at much lower temperatures (40-90°C) to dissolve metals from black mass, achieving comparable metal recovery without the high energy consumption and toxic gas emissions associated with pyrometallurgical processes.
3Manufacturing precision
If conventional hydrometallurgical separation processes are used, then metals can be separated, but process complexity increases and capital expenditures rise
Solution Approach 1:
The patent recovers and reuses H2SO4 from the leaching process by treating the spent leach solution with Ca(OH)2 to precipitate impurities, then recovering the H2SO4 for reuse in subsequent leaching operations. This circular approach reduces the need for continuous fresh reagent addition and complex waste treatment systems, thereby simplifying the overall process while maintaining high metal separation purity.
4Productivity
If higher temperature is used to improve acid leaching kinetics, then leaching rate increases, but H2O2 decomposition accelerates and reductive power is lost
Solution Approach 1:
The leaching process is divided into two distinct stages: Stage 1 uses only H2SO4 at elevated temperature (70-90°C) for initial metal dissolution, while Stage 2 uses H2SO4 + H2O2 at lower temperature (40-60°C) for complete leaching. This segmentation allows each stage to operate under optimal conditions, preventing H2O2 decomposition that would occur if it were added in the first stage, thereby reducing H2O2 consumption while maintaining high metal recovery quantities.
Solution Approach 2:
In Stage 1, the patent performs preliminary leaching using only H2SO4 at high temperature to dissolve easily leachable metals and prepare the black mass for the second stage. This preliminary action removes the need to use H2O2 at high temperature, preserving its reductive power for Stage 2 where it is applied at lower temperatures (40-60°C) to reduce Co3+ and Mn4+ and achieve complete metal dissolution, thereby preventing H2O2 decomposition and maintaining its effectiveness.
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 reduces H2O2 consumption, ensures efficient use of reducing agents, and achieves high-purity metal recovery with approximately 60% lower capital costs and 50% lower reagent and utility costs compared to traditional methods, while maintaining product quality.
Implementation Method 1
The first step is leaching the metals from black mass. A common leaching agent is sulfuric acid (H2SO4)
Implementation Method 2
hydrogen peroxide (H2O2) as the reducing agent. Reduction is required because of the presence of higher valence state species, such as Co3+ and Mn4+, in the black mass
Implementation Method 3
A two-stage leaching process is employed, where acid leaching is followed by reductive leaching with H2O2
Data Source
AI summary
A process for recovering and purifying nickel (Ni), manganese (Mn), cobalt (Co), and lithium (Li) from black mass obtained from recycling of lithium-ion batteries to produce high purity products. The process may include reductive acid leaching, impurity removal, precipitation of valuable metals such as Ni, Co, Mn, and Li. The process may also include recycling of Li compounds as hydroxide or carbonate as a source of alkaline reagent for impurity removal and/or precipitation of the valuable metals.