Chemical Recovery of Zinc Oxalate and Manganese Dioxide from Battery Black Paste
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Solution Overview
Problem
Current battery recycling processes face inefficiencies due to the mixing of unknown compositions after battery separation, leading to high energy and environmental costs in pyrometallurgical treatments.
Innovation Solution
A chemical treatment process involving selective dry extraction, water washing, sulfuric acid treatment, oxalic acid precipitation, and electrolysis to recover zinc oxalate and electrolytic manganese dioxide from alkaline and zinc-carbon battery black pastes, allowing for the separation and recycling of recyclable raw materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If pyrometallurgical treatment is used for battery recycling, then complete material recovery is achieved, but energy consumption and environmental costs increase significantly
Solution Approach 1:
The recycling process is divided into distinct stages: mechanical separation to isolate black paste, selective dissolution to separate zinc and manganese compounds, and targeted precipitation to recover pure materials. This segmentation allows each stage to be optimized independently, avoiding the high energy costs of complete pyrometallurgical processing while ensuring thorough material recovery.
Solution Approach 2:
The process utilizes controlled changes in chemical parameters (pH, concentration, temperature) to selectively dissolve and precipitate different battery components. By adjusting these parameters, zinc and manganese can be recovered in high purity through wet chemical methods, eliminating the need for energy-intensive melting and refining operations.
2Ease of manufacture
If batteries are ground and washed with water to extract black paste components, then material separation is achieved, but the composition becomes unknown and variable
Solution Approach 1:
The process incorporates analytical monitoring to track the composition of the black paste and subsequent solution phases. This feedback enables real-time adjustment of dissolution and precipitation conditions, ensuring consistent recovery of zinc and manganese regardless of variations in incoming battery composition.
Solution Approach 2:
By systematically controlling chemical parameters such as acid concentration, pH, and precipitation conditions, the process transforms variable black paste compositions into consistent, high-purity product streams. The controlled parameter changes ensure that zinc and manganese are reliably separated and recovered in predictable quantities and purities.
3Manufacturing precision
If selective chemical treatment is applied to black paste, then high-purity zinc oxalate and manganese dioxide are recovered, but process complexity increases
Solution Approach 1:
The process selectively extracts zinc and manganese from the black paste through controlled dissolution, then separates them via selective precipitation. Zinc is precipitated as oxalate while manganese remains in solution, and vice versa in subsequent steps. This targeted extraction approach achieves high purity products through straightforward chemical separations rather than complex multi-step procedures.
Solution Approach 2:
Oxalic acid serves as an intermediary reagent that selectively precipitates zinc from the dissolved black paste, while manganese remains in solution. This intermediary substance enables clean separation of the two metals without requiring complex equipment or multiple processing stages, maintaining process simplicity while achieving high purity recovery.
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 process enables effective and environmentally friendly recovery of recyclable materials, reducing energy and environmental costs by achieving high-purity zinc oxalate and manganese dioxide recovery, with additional by-products for industrial and agricultural use.
Implementation Method 1
washing the black paste with water to separate the potassium hydroxide of the alkaline batteries and the ammonium chloride of zinc-carbon batteries in the form of a solution
Implementation Method 2
treatment of the wet black paste resulting from step b) with an aqueous solution of sulfuric acid, achieving the solubilisation of metallic zinc and of its compounds and of manganese compounds
Implementation Method 3
treating the sulfuric solution obtained in step d) with oxalic acid in sub-stoichiometric amounts compared to zinc, obtaining the precipitation of zinc oxalate
Implementation Method 4
electrolysis of the acid solution with formation of MnO2 at the anode
Implementation Method 5
electrolysis of the acid solution with formation of MnO2 at the anode
Data Source
AI summary
A process is described for the recovery of the chemical components of the “black paste” resulting from the opening of dead alkaline and zinc-carbon batteries.