High Purity Tin Electrowinning with Lead Removal
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Solution Overview
Problem
Current methods for manufacturing high purity tin are costly and inefficient, with high α ray emission and low productivity due to the presence of impurities like lead and antimony, and the use of expensive electrolytic solutions and complex temperature control processes.
Innovation Solution
The method involves electrowinning tin using a sulfuric acid solution with a smoothing agent and a diaphragm between the anode and cathode to remove lead from the electrolyte, resulting in plate-shaped electrodeposited tin with reduced impurities and lower α ray emission, which can be melted and cast in air, reducing costs and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorosilicic acid and sulfuric acid mixed electrolytic solution is used, then electrowinning can be performed, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive fluorosilicic acid-based electrolytic solution with a cheaper sulfuric acid-based electrolytic solution. The electrolytic solution is continuously refreshed by circulating it through a purification system that removes lead and other impurities, allowing the use of a less expensive but shorter-lived electrolyte composition that can be regenerated rather than discarded.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolytic solution from fluorosilicic acid and sulfuric acid mixture to primarily sulfuric acid with controlled impurity levels. By adjusting the purity requirements and using continuous purification, the system achieves effective electrowinning with a simpler, cheaper electrolyte formulation.
2Manufacturing precision
If temperature control in setting tank is implemented, then lead precipitation is improved, but process complexity increases
Solution Approach 1:
The patent removes the complex temperature control system from the electrowinning process. Instead of controlling temperature to precipitate lead, the invention extracts and removes lead through continuous circulation and filtration of the electrolytic solution through a purification system that operates at ambient or controlled conditions without requiring sophisticated thermal management.
Solution Approach 2:
The patent replaces the mechanical/thermal control system (temperature control in setting tank) with a chemical/filtration-based system. Lead removal is achieved through circulation and filtration rather than temperature-induced precipitation, substituting a complex thermal control mechanism with a simpler filtration-based purification approach.
3Manufacturing precision
If diaphragm is added between anode and cathode, then lead purification is improved, but device complexity increases
Solution Approach 1:
The patent introduces a circulation system as an intermediary between the electrolytic bath and the purification process. Rather than using a diaphragm to physically separate anode and cathode compartments, the invention uses a circulating electrolytic solution that passes through a purification system (filtration and chemical treatment) to remove lead, achieving purification through a mediating fluid transport mechanism rather than direct physical separation.
4Quantity of substance
If refined and unrefined electrolytic solutions are mixed, then lead dilution is achieved, but purification effectiveness decreases
Solution Approach 1:
The patent applies preliminary action by continuously purifying the electrolytic solution before it is used in electrowinning. Rather than mixing refined and unrefined solutions to dilute lead, the system pre-purifies the electrolyte by circulating it through a filtration and chemical treatment system that removes lead and other impurities before the solution contacts the electrodes, ensuring high purification effectiveness from the outset.
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 significantly reduces the manufacturing cost and improves the productivity of high purity tin with decreased α ray emission, achieving purities of 4N or higher and impurity levels below 0.1 ppm, while allowing for air casting without oxidation issues.
Implementation Method 1
depositing electrodeposited tin on the surface of a cathode by electrowinning in an electrolytic bath
Implementation Method 2
a diaphragm is placed between an anode and the cathode
Implementation Method 3
the electrolytic solution contains a smoothing agent for improving a surface property of the electrodeposited tin
Implementation Method 4
a leachate obtained by electrolytically leaching the raw material for tin in a sulfuric acid solution as an electrolytic solution
Data Source
AI summary
Provided is a method for manufacturing high purity tin including: depositing electrodeposited tin on the surface of a cathode by electrowinning in an electrolytic bath in which a diaphragm is placed between an anode and the cathode, by using a raw material for tin as the anode and a leachate obtained by electrolytically leaching the raw material for tin in a sulfuric acid solution as an electrolytic solution, the electrolytic solution containing a smoothing agent for improving a surface property of the electrodeposited tin; discharging the electrolytic solution from the electrolytic bath such that lead in the discharged electrolytic solution is removed; and putting the electrolytic solution from which lead is removed back into the electrolytic bath.