Closed-Loop Leaching Mixture Recycling for Lead Purification
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Solution Overview
Problem
Existing methods for purifying lead from spent lead-acid batteries rely heavily on costly and complex pyrometallurgical smelting, producing harmful byproducts and requiring costly scrubbing processes, while also failing to efficiently recycle the liquid components of the leaching mixture.
Innovation Solution
A closed-loop system that forms a leaching mixture with a lead-bearing material, a carboxylate source, and a recycled liquid component to generate a lead salt precipitate, isolates and recycles the liquid component, and purifies it to reduce sulfate content, thereby enhancing lead recovery and reducing waste disposal costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pyrometallurgical smelting is used to purify lead from spent lead-acid batteries, then lead purification can be achieved, but harmful byproducts are produced and costly scrubbing processes are required
Solution Approach 1:
The patent changes the fundamental parameters of the purification process by replacing high-temperature pyrometallurgical methods with low-temperature hydrometallurgical methods. The leaching mixture uses aqueous solutions at moderate temperatures to dissolve lead compounds, followed by precipitation to purify lead. This parameter change eliminates the combustion reactions that produce harmful byproducts while maintaining effective lead purification.
Solution Approach 2:
The patent substitutes mechanical/thermal processes (smelting, combustion, scrubbing) with chemical processes (leaching, precipitation). Instead of using heat and mechanical separation, the invention employs chemical reactions in aqueous solution to transfer and purify lead, replacing the entire pyrometallurgical system with a hydrometallurgical system that inherently avoids harmful emissions.
2Productivity
If pyrometallurgical smelting is used for lead purification, then lead recovery can be achieved, but the process complexity and cost increase due to specialized equipment and consumables
Solution Approach 1:
The patent extracts the lead from the complex battery waste matrix using a selective leaching process. By using aqueous carboxylic acid solutions, the method selectively dissolves lead compounds while leaving other materials behind, then precipitates the lead in a purified form. This extraction approach simplifies the overall process by separating the lead recovery function from the complex smelting operations required by traditional methods.
Solution Approach 2:
The patent introduces an intermediary leaching mixture (aqueous carboxylic acid solution) that mediates between the solid battery waste and the purified lead product. This liquid intermediary facilitates the transfer of lead from the complex waste matrix to a purified state through dissolution and precipitation, eliminating the need for complex high-temperature equipment and specialized consumables required in direct smelting processes.
3Productivity
If traditional lead purification methods are used, then lead can be recovered, but the liquid components of the leaching mixture are not efficiently recycled
Solution Approach 1:
The patent implements a closed-loop system where the liquid component of the leaching mixture is recovered after lead precipitation and reused in subsequent leaching operations. Instead of discarding the spent leaching solution, the system filters out the precipitated lead and recycles the liquid back into the process, continuously recovering both the lead product and the valuable liquid medium, thereby eliminating substance loss and reducing waste disposal requirements.
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 enables efficient, cost-effective lead recovery and purification, reduces the production of harmful byproducts, and enhances the recycling of the liquid component, improving overall lead recovery efficiency and industrial scalability.
Implementation Method 1
a reactor that receives and mixes a lead-bearing material waste, a carboxylate source, and a recycled liquid component to form a leaching mixture yielding a lead salt precipitate
Implementation Method 2
a phase separation device coupled to the reactor, wherein the phase separation device isolates the lead salt precipitate from a liquid component of the leaching mixture
Data Source
AI summary
The present disclosure relates generally to systems and methods for recycling lead-acid batteries, and more specifically, relates to purifying and recycling the lead content from lead-acid batteries. A system includes a reactor that receives and mixes a lead-bearing material waste, a carboxylate source, and a recycled liquid component to form a leaching mixture yielding a lead carboxylate precipitate. The system also includes a phase separation device coupled to the reactor, wherein the phase separation device isolates the lead carboxylate precipitate from a liquid component of the leaching mixture. The system further includes a closed-loop liquid recycling system coupled to the phase separation device and to the reactor, wherein the closed-loop liquid recycling system receives the liquid component isolated by the phase separation device and recycles a substantial portion of the received liquid component back to the reactor as the recycled liquid component.