Lithium-Ion Battery Roasting Process for Phosphate-Safe Lithium Elution
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Solution Overview
Problem
Current methods for recovering lithium from waste lithium-ion batteries, particularly those with phosphorus-containing cathode active materials, face challenges such as low throughput, complex process steps, and difficulty in eluting lithium due to the formation of water-insoluble lithium phosphate.
Innovation Solution
A system and method that involves mixing a non-lithium alkali metal salt with the cathode active material, grinding it to facilitate decomposition during roasting, and then immersing the roasted product in water to elute lithium, preventing the formation of insoluble lithium phosphate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrothermal treatment is performed in a hermetically sealed pressure vessel, then lithium extraction is achieved, but treatment capacity is low and throughput is slow
Solution Approach 1:
The patent changes the physical state of the reaction system from sealed high-pressure hydrothermal conditions to open atmospheric roasting conditions. By changing the pressure parameter from high pressure to atmospheric pressure, and the reaction environment from aqueous hydrothermal to oxidative roasting, the system achieves both effective lithium extraction and high throughput processing capability.
Solution Approach 2:
The patent utilizes phase transition of water from liquid (hydrothermal treatment) to vapor (roasting atmosphere). The roasting process uses water vapor generated during heating to create an oxidative environment that facilitates lithium extraction, eliminating the need for sealed pressure vessels while maintaining extraction effectiveness.
2Object-generated harmful factors
If alkaline earth metal hydroxide is added during oxidizing roasting, then fluorine and phosphorus are converted to solid compounds, but lithium may bond to phosphate ions forming water-insoluble lithium phosphate
Solution Approach 1:
The patent introduces alkali metal salt as an intermediary substance that preferentially reacts with phosphate ions to form alkali metal phosphate. This intermediary reaction prevents lithium from bonding with phosphate to form insoluble lithium phosphate, while still achieving phosphorus removal. The alkali metal salt acts as a mediator that protects lithium solubility while removing harmful phosphorus.
Solution Approach 2:
The patent converts the potential harm of phosphorus forming insoluble lithium phosphate into a benefit by using alkali metal salt to selectively bind phosphate ions. The reaction between alkali metal salt and phosphate ions, which could be seen as a competing reaction, actually benefits the process by preventing lithium phosphate precipitation and ensuring lithium remains soluble for extraction.
3Reliability
If complex process steps are used for lithium recovery, then lithium extraction is achieved, but operation management becomes difficult and facility complexity increases
Solution Approach 1:
The patent merges multiple process steps into a single integrated roasting operation. By combining phosphorus removal, lithium extraction, and impurity elimination into one atmospheric roasting step with alkali metal salt addition, the process eliminates the need for separate hydrothermal treatment, pressure vessel operations, and multiple processing stages, significantly simplifying facility complexity and operation management.
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 allows for the efficient recovery of lithium from waste lithium-ion batteries with phosphorus-containing cathode active materials by eluting it into water without complex process steps, increasing the elution rate and preventing lithium from becoming insoluble.
Implementation Method 1
The mixing equipment kneads the alkali metal salt into the cathode active material while grinding the alkali metal salt
Implementation Method 2
roasting a waste lithium-ion battery whose cathode active material contains phosphorus to obtain a roasted product
Implementation Method 3
immersing the roasted product in water to elute lithium from the roasted product into the water
Data Source
AI summary
A waste lithium-ion battery processing system is a system for processing a waste lithium-ion battery, the system performing roasting a waste lithium-ion battery whose cathode active material contains phosphorus to obtain a roasted product and immersing the roasted product in water to elute lithium from the roasted product into the water, thereby recovering the lithium from the waste lithium-ion battery. The system includes: mixing equipment that mixes a non-lithium alkali metal salt into the cathode active material contained in the waste lithium-ion battery; and a roaster that roasts, at a predetermined first temperature, a mixture that is obtained from mixing by the mixing equipment. The mixing equipment kneads the alkali metal salt into the cathode active material while grinding the alkali metal salt.