Lithium Battery Cathode Plate Recovery With Aluminum and Fluorine Removal
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Solution Overview
Problem
Existing methods for recovering lithium battery positive electrode plates suffer from complicated steps, incomplete impurity removal, and low valuable metal recovery rates, particularly due to the inefficiencies in removing aluminum and fluorine impurities.
Innovation Solution
A method involving a replacement reaction with a metal salt to remove aluminum impurities and a defluorination process using basic sodium aluminum sulfate to purify the leaching solution, followed by extraction and precipitation steps to recover transition metals and lithium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pH value is adjusted to 4.0-6.0 to remove iron and aluminum, then iron and aluminum are removed from the solution, but nickel, cobalt and manganese metals are precipitated and lost
Solution Approach 1:
The patent applies preliminary action by adding iron powder to reduce nickel, cobalt and manganese to their metallic states before pH adjustment. This preliminary reduction prevents these valuable metals from being precipitated when pH is later adjusted to remove iron and aluminum impurities, thereby solving the contradiction between complete impurity removal and valuable metal preservation
Solution Approach 2:
The patent uses iron powder as an intermediary substance that serves multiple functions: it reduces nickel, cobalt and manganese to metallic states, and simultaneously serves as a removable carrier that can be filtered out along with iron and aluminum hydroxide precipitates. This intermediary approach allows selective removal of impurities without losing valuable metals
2Loss of substance
If traditional hydrometallurgical process is used, then valuable metals can be recovered, but the process steps are complicated and valuable metal recovery rate is reduced due to precipitation losses
Solution Approach 1:
The patent extracts and removes the problematic pH adjustment step from the traditional process by directly filtering the leaching solution after acid leaching. This extraction of the problematic step eliminates the need for complex pH adjustment and multiple precipitation steps, thereby simplifying the process while maintaining high valuable metal recovery rates
Solution Approach 2:
The patent discards the conventional wisdom of using pH adjustment for impurity removal and instead directly filters the leaching solution. This approach discards the complicated multi-step precipitation process while recovering all valuable metals through simple filtration, achieving both process simplification and high metal recovery
3Ease of manufacture
If aluminum and fluorine impurities are not thoroughly removed, then the process is simpler, but the quality of recovered metals is reduced and equipment corrosion increases
Solution Approach 1:
The patent applies preliminary action by adding iron powder before filtration to reduce nickel, cobalt and manganese to metallic states. This preliminary reduction ensures that when filtration occurs, only iron and aluminum impurities are removed while valuable metals remain in solution, achieving both process simplicity and high metal recovery quality
Solution Approach 2:
The patent replaces the complex chemical precipitation system (pH adjustment, multiple reagents) with a simpler mechanical filtration system. By using iron powder reduction followed by direct filtration, the process achieves thorough impurity removal and high metal quality without the complexity of traditional chemical precipitation methods
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
The method achieves high aluminum removal rates (>98%) and fluorine removal rates (>99%), enhancing the recovery of transition metals and lithium while reducing production costs and safety risks associated with hydrogen production.
Implementation Method 1
reacting a material of a positive electrode plate with a metal salt in an aqueous solution... in the step S1, a standard electrode potential of the metal in the metal salt is higher than that of aluminum
Implementation Method 2
dissolving and leaching a solid obtained in the step S1 with a mixed solution of an acid and a reducing agent
Implementation Method 3
defluorinating a leaching solution obtained in the step S2... using basic sodium aluminum sulfate to purify the leaching solution
Implementation Method 4
extracting a transition metal in the leaching solution
Implementation Method 5
precipitating and separating out lithium in a raffinate
Data Source
Figure 1
AI summary
Disclosed in the present invention is a method for recovering a lithium battery positive electrode plate. A method for recovering a lithium battery positive electrode plate. The method comprises the following steps: S1. reacting a positive electrode plate material with a metal salt in an aqueous solution, wherein the standard electrode potential of metal in the metal salt is higher than that of aluminum; S2. dissolving and soaking a solid obtained in step S1 with a mixed solution of an acid and a reducing agent; and S3. subjecting a leachate obtained in step S2 to a fluorine removal treatment, then extracting a transition metal in the leachate, and precipitating and separating lithium from the raffinate. In the method for recovering a lithium battery positive electrode plate of the present invention, aluminum impurities in the positive electrode plate material and fluorine impurities in the leachate can be thoroughly removed by means of the cooperation of all the steps and the raw materials used; in addition, it is guaranteed that the loss rate of valuable metal in the positive electrode plate material is ≤ 0.1%.