Lead and Tin Recovery via Deep Eutectic Solvent Leaching

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Solution Overview

Problem

Current recycling methods for lead and tin from lead-based materials, such as lead acid batteries and solar cells, are energy-intensive and polluting, with no effective methods for recycling lead telluride thermoelectrics and lead perovskite solar cells, posing environmental risks and limiting their application.

Innovation Solution

A low-energy and low-pollution chemical method using a deep eutectic solvent and a compound with a carboxylic acid moiety to precipitate lead and tin carboxylates from lead- and tin-based materials, allowing for the extraction and recycling of lead and tin with reduced environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If pyrometallurgical process is used to recycle lead from lead-acid batteries, then lead recovery rate is improved (up to 98%), but energy consumption increases significantly and CO2 emissions are produced

Engineering Contradiction:

Improvelead recovery rateVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the fundamental parameter of processing temperature from high-temperature pyrometallurgy to low-temperature hydrometallurgy. The chemical leaching process operates at near room temperature, dramatically reducing energy consumption while maintaining effective lead recovery through solution-based chemistry rather than thermal processing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal/mechanical pyrometallurgical system with a chemical hydrometallurgical system. Instead of using heat and mechanical separation, the invention uses chemical leaching with acids or alkalis to dissolve lead compounds, followed by electro-winning to precipitate pure lead, substituting thermal energy with chemical and electrical energy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If pyrometallurgical process is used to recycle lead from lead-acid batteries, then lead recovery rate is improved (up to 98%), but harmful emissions (CO2 and lead-to-air emissions) increase

Engineering Contradiction:

Improvelead recovery rateVSAvoidharmful emissions

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the thermal pyrometallurgical system that generates harmful emissions with a chemical hydrometallurgical system operating in closed vessels. The chemical leaching and electro-winning processes occur in controlled aqueous environments, eliminating open-flame combustion and associated CO2 and particulate emissions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a controlled, inert aqueous environment for the leaching and electro-winning processes. By conducting reactions in closed systems with controlled chemistry rather than open high-temperature processing, the invention prevents lead dust and CO2 from being released into the atmosphere

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Object-generated harmful factors

If hydrometallurgical route with electro-winning is used to produce metallic Pb, then harmful emissions (SO2 and lead dust) are reduced, but energy efficiency decreases due to low solubility of lead compounds

Engineering Contradiction:

Improveharmful emissionsVSAvoidenergy efficiency

Core Design Contradiction:

Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical parameters of the leaching solution to optimize both solubility and energy efficiency. By selecting specific acids or alkalis and adjusting concentration, temperature, and pH, the invention achieves high solubility of lead compounds in the leaching stage, which then requires less energy for the subsequent electro-winning precipitation stage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a continuous process where the leaching solution is directly fed into the electro-winning cell without intermediate steps. The lead compounds dissolved in the leaching solution are immediately precipitated as metallic lead at the cathode, maintaining continuous useful action and maximizing energy efficiency by eliminating idle time and redundant processing steps

Inventive Principle:

Principle #20Continuity of useful action

4Productivity

If traditional smelting and hydrometallurgical routes are used for recycling, then lead can be recovered, but energy consumption is high and pollution occurs

Engineering Contradiction:

Improvelead recoveryVSAvoidpollution

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces traditional smelting (thermal/mechanical) and conventional hydrometallurgy with an integrated low-temperature chemical process. The combination of chemical leaching followed by electro-winning occurs in closed systems at near room temperature, eliminating the high-energy consumption and pollution associated with both traditional methods while maintaining effective lead recovery

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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 recycles lead and tin with minimal energy consumption and pollution, providing a sustainable alternative to traditional smelting and hydrometallurgical processes, and enables the reuse of lead in new battery electrodes.

Implementation Method 1

combining a lead- and/or tin-based material, or a mixture thereof, and a compound comprising a carboxylic acid moiety in the presence of a deep eutectic solvent

Methodology Applied

Scientific EffectSolvation: Solvation