Battery Metal Recovery Using Lithium Solution pH Reuse
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Solution Overview
Problem
Current methods for recovering valuable metals from waste lithium ion batteries, such as hydrometallurgy, face challenges including low lithium recovery rates and environmental issues like ecotoxicity due to wastewater discharge.
Innovation Solution
A method involving a reduction and heat treatment step, followed by water washing, acid washing, and valuable metal precipitation steps, where a reducing agent is added to the waste battery material, and the first aqueous lithium solution from the water washing step is used as a pH adjuster in the precipitation step to recover nickel, cobalt, and manganese while minimizing wastewater generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrometallurgy is used to recover valuable metals from waste battery material, then valuable metals can be recovered, but lithium recovery rate is low and wastewater is generated causing environmental problems
Solution Approach 1:
The patent changes the pH parameter dynamically during the process. In the leaching stage, acidic conditions (pH 2-4) are maintained to dissolve valuable metals. In the precipitation stage, the pH is adjusted to alkaline conditions (pH 8-10) to selectively precipitate metals. This parameter change enables both effective metal recovery and reduced wastewater impact through controlled chemical environments.
Solution Approach 2:
The patent utilizes phase transitions of metals between dissolved and precipitated states. Valuable metals are first dissolved in acidic solution, then selectively precipitated as hydroxides or carbonates by adjusting pH. This phase transition approach enables separation and concentration of metals while minimizing wastewater volume through controlled chemical transformations.
2Reliability
If conventional pH adjusters are used in the valuable metal precipitation step, then nickel, cobalt, and manganese can be precipitated, but wastewater volume increases and processing cost increases
Solution Approach 1:
The patent employs the first aqueous lithium solution, generated during the water washing step, to serve as the pH adjuster in the precipitation step. This self-service approach eliminates the need for additional alkaline reagents, reduces wastewater volume by reusing process water, and lowers processing costs. The lithium solution naturally provides the necessary alkalinity for metal precipitation while recovering lithium simultaneously.
Solution Approach 2:
The first aqueous lithium solution performs multiple functions: it washes the leached material, recovers lithium through dissolution, and serves as the pH adjuster for precipitation. This multi-functionality reduces the need for separate chemical additives and minimizes overall wastewater generation by integrating multiple process steps into a unified system.
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 effectively recovers valuable metals from waste lithium ion batteries, reduces wastewater generation, and lowers the cost of processing wastewater by utilizing the first aqueous lithium solution as a pH adjuster.
Implementation Method 1
a reduction and heat treatment step comprising adding a reducing agent to a raw material including the waste battery material and the waste cathode active materials and heat-treating the raw material
Implementation Method 2
a water washing step comprising adding water to the heat-treated raw material to obtain a first aqueous lithium solution in which the lithium compound is dissolved
Implementation Method 3
adding an acidic solubilizer to the water washing residue to obtain an acid solution in which the valuable metals including lithium, nickel, cobalt, and manganese are dissolved
Implementation Method 4
adding a pH adjuster to increase pH to the acid solution to obtain a precipitation residue in which nickel, cobalt, and manganese are precipitated
Data Source
AI summary
A present disclosure provides a method for recovering a valuable metal from a waste battery material and a waste cathode active materials which can reduce wastewater and the cost of processing wastewater by replacing a first aqueous lithium solution including an alkaline substance produced in the process of recovering a valuable metal from a waste battery material and a waste cathode active materials by a pH adjuster.