Lithium-Ion Cathode Recycling With Formate-Based Metal Separation
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Solution Overview
Problem
Current hydrometallurgical processes for recycling lithium-ion battery cathode materials face inefficiencies in metal recovery, particularly in separating and recovering lithium, nickel, cobalt, and manganese, and often produce waste products that complicate recycling and are environmentally harmful.
Innovation Solution
A hydrometallurgical process using formic acid to leach lithium-ion battery cathode materials, forming metal formates that precipitate based on solubility differences, followed by thermal decomposition to recover lithium carbonate and sulfuric acid treatment to produce high-purity metal sulfates, with closed-loop recycling of formic acid and carbon dioxide reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrometallurgical processes use inorganic acids for leaching, then leaching efficiency is improved, but toxic wastewater is produced and equipment corrosion increases
Solution Approach 1:
The patent changes the chemical nature of the leaching agent from inorganic acid to organic acid (formic acid), fundamentally altering the chemical parameters of the leaching process to eliminate toxic wastewater while maintaining effective metal dissolution
Solution Approach 2:
The patent employs formic acid, an organic acid that decomposes into harmless substances (carbon dioxide and water), replacing persistent inorganic acids that create long-term environmental contamination and equipment damage
2Productivity
If sodium carbonate is used to precipitate lithium carbonate, then lithium recovery is achieved, but sodium waste is produced that complicates separation and recyclability
Solution Approach 1:
The patent uses formic acid and its byproducts (carbon dioxide and water) within the same process system, creating a self-sustaining cycle where waste products become useful resources for process continuation, eliminating external waste disposal needs
Solution Approach 2:
The patent recovers and reuse s formic acid from the leaching process through distillation, while carbon dioxide byproduct is captured for potential reuse, transforming what would be discarded waste streams into valuable process inputs
3Manufacturing precision
If additional separation and purification steps are added to recover metals, then metal purity is improved, but process complexity and cost increase
Solution Approach 1:
The patent selectively extracts different metal ions from the leachate solution by controlling pH and using selective precipitants, separating metals in a staged manner that achieves high purity without requiring multiple complex purification units
Solution Approach 2:
The patent applies different chemical conditions (pH levels, reagent types) to different stages of the separation process, optimizing each separation step locally to achieve cumulative high-purity metal recovery through a manageable sequence of operations
4Object-generated harmful factors
If formic acid leaching is used, then green chemistry and waste reduction are achieved, but leaching rate may be reduced compared to inorganic acids
Solution Approach 1:
The patent optimizes formic acid concentration, temperature, and contact time parameters to maximize the leaching rate of formic acid, demonstrating that organic acids can achieve competitive dissolution speeds while maintaining environmental benefits
Solution Approach 2:
The patent employs continuous leaching operations with optimized flow rates and residence times, ensuring that the slower-forming but environmentally benign formic acid leaching process operates at sustained high efficiency throughout the treatment period
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
Achieves high recovery rates of lithium, nickel, and manganese with minimal waste production, optimizing leaching and precipitation conditions through statistical modeling, and producing high-purity metals suitable for battery manufacturing.
Implementation Method 1
leaching the metal-containing material with formic acid; obtaining a leachate solution comprising the one or more metals as one or more metal formates
Implementation Method 2
precipitating at least one of the one or more metal formates
Implementation Method 3
The filtrate is concentrated and heated to nearly 100° C. and then saturated with sodium carbonate, which precipitates lithium carbonate
Data Source
AI summary
A green chemistry hydrometallurgical process for recovering one or more metals from a metal-containing material includes leaching the metal-containing material with formic acid, obtaining a leachate comprising the one or more metals as one or more metal formates, and precipitating at least one of the one or more metal formates. The metal-containing material may be a lithium-ion battery cathode material, resulting in Li formate remaining in solution and precipitation of salts including one or more of Ni, Co, and Mn formates. Steps may include filtration of the leachate, sulphurization of retained metal formate salts to produce metal sulphate salts, purification of filtered leachate by adding lithium carbonate and filtering, dewatering of the purified leachate, and thermal decomposition of resulting lithium salts to produce battery grade lithium carbonate. Carbon dioxide, water, and formic acid may be recovered and reused, without liquid or solid waste produced.