Direct Lead Oxide Recovery from Waste Paste via Barium Desulfurization
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Solution Overview
Problem
Current methods for recovering lead oxide from waste lead paste are inefficient, requiring complex processes, high energy consumption, and failing to utilize barium sulfate additives effectively, leading to high costs and environmental pollution.
Innovation Solution
A method involving a desulphurization reaction with a barium-containing agent followed by a pyrolytic conversion at 350-750°C to directly produce lead oxide, utilizing NaOH or KOH solutions with soluble barium compounds to recover lead oxide while minimizing energy consumption and incorporating barium sulfate as an additive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyrometallurgy is used for lead recovery, then large-scale continuous production is achieved, but high energy consumption and lead emission occur
Solution Approach 1:
The patent changes the temperature parameter from high-temperature pyrometallurgy (1100-1300°C) to low-temperature hydrometallurgy (350-750°C), fundamentally altering the energy consumption profile while maintaining production capability through a different chemical mechanism (acid leaching followed by controlled thermal decomposition)
Solution Approach 2:
The patent replaces the thermal-mechanical pyrometallurgical system with a chemical-hydrometallurgical system using acid leaching and controlled precipitation, substituting high-energy thermal processes with lower-energy chemical reactions that achieve the same lead recovery objective
2Productivity
If pyrometallurgy is used for lead recovery, then continuous production is achieved, but lead-containing dust and waste residue are produced
Solution Approach 1:
The patent converts the harmful high-temperature volatilization process into a beneficial controlled low-temperature decomposition process, where lead compounds are transformed into soluble salts through acid leaching, then precipitated as pure lead oxide, turning potential emissions into recoverable product
Solution Approach 2:
The patent introduces acid leaching solution as an intermediary medium that facilitates lead extraction without direct high-temperature heating, using chemical dissolution and controlled precipitation to achieve lead recovery without generating dust emissions
3Manufacturing precision
If conventional lead smelting process is used, then refined lead is produced, but lead oxide required for battery active material is not directly obtained
Solution Approach 1:
The patent performs preliminary acid leaching to convert lead compounds into soluble salts before the main recovery step, preparing the material in advance for direct precipitation as lead oxide, thereby eliminating the need for subsequent refining steps
Solution Approach 2:
The patent inverts the conventional approach by not smelting lead oxide into metal and then re-oxidizing it, but instead directly recovering lead oxide from waste paste through acid leaching and controlled precipitation, achieving the desired product form in a single process sequence
4Loss of substance
If barium-containing desulfurizing agent is used, then barium sulfate additive is recovered and reused, but process complexity increases
Solution Approach 1:
The patent merges the desulfurization function and barium sulfate recovery function into a single integrated step by using barium-containing desulfurizing agent, where the same chemical process that removes sulfur also recovers the barium additive for reuse in battery production
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 reduces energy consumption, eliminates incomplete reactions, and effectively recovers lead oxide with improved activity, allowing for the reuse of barium sulfate, thus enhancing the recycling value of lead paste and reducing environmental impact.
Implementation Method 1
controlling waste lead paste to contact with a barium-containing desulfurizing agent under desulphurization reaction conditions
Implementation Method 2
controlling the filter residue to have a conversion reaction at 350-750°C temperature, to convert the lead-containing components in the filter residue into lead oxide
Implementation Method 3
the conversion reaction in step (2) is carried out in existence of a promoter for atom-economic reaction
Data Source
AI summary
Provided is a method for directly recovering lead oxide used for a lead-acid battery negative electrode from waste lead paste. The method comprises: (1) contacting waste lead paste with a barium-containing desulphurizer under desulphurization reaction conditions, and performing a solid-liquid separation on the mixture after contacting to obtain a filtrate and a filtration residue; and (2) performing a conversion reaction on the above-mentioned filtration residue at a temperature of 350-750°C so as to convert the lead-containing components in the filtration residue into lead oxide. In the method, the direct recovery of a lead oxide raw material applicable to a lead-acid battery negative electrode from waste lead paste is achieved by quantitatively replenishing a barium sulphate additive in the process of desulphuration, thereby substantially decreasing the recovery cost and energy consumption, and improving the comprehensive utilization of waste lead paste.