Solder Slag Reduction With Copper Addition for Metal Purity
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Solution Overview
Problem
Current processes for producing copper and solder products from secondary feedstocks face challenges such as low purity, high contaminant levels, and inefficient recovery of valuable metals like tin and lead, leading to increased chemical consumption and environmental concerns.
Innovation Solution
A process that involves partial reduction and separation of solder refining slags, with the addition of copper to favor the movement of tin and lead into the metal phase, reducing the concentration of these metals in the spent slag and allowing for higher recovery and purification of valuable metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If secondary feedstocks are used for copper production, then metal recovery becomes more sustainable and economically viable, but the purity of the metal product decreases and contaminant levels increase
Solution Approach 1:
The invention divides the complex multi-metal feedstock into separate processing streams: a copper-rich stream and a solder-rich stream (tin-lead). By segmenting the feedstock and processing them through different pyrometallurgical pathways, the process achieves high purity in each product stream while efficiently recovering valuable metals from low-grade secondary feedstocks.
Solution Approach 2:
The invention applies local quality by creating different chemical environments in different zones of the furnace. The copper stream receives specific fluxes and operating conditions optimized for copper recovery, while the solder stream receives different flux compositions and treatment parameters optimized for tin-lead recovery. This localized optimization allows each stream to achieve high purity despite starting from impure secondary feedstocks.
2Productivity
If multiple metals are recovered from the same feedstock, then resource efficiency increases, but the complexity of the separation process and chemical consumption increase
Solution Approach 1:
The invention segments the multi-metal recovery process into distinct copper and solder streams, each with its own optimized separation pathway. This avoids the need for complex multi-stage separation processes that would be required to recover all metals simultaneously from a single mixed stream.
Solution Approach 2:
The invention uses a multi-functional furnace system that can handle both copper and solder recovery in the same equipment. The furnace is designed to accommodate different feedstock types and processing conditions, allowing it to perform multiple functions: copper smelting, solder refining, and waste heat generation, thereby reducing overall process complexity while maintaining high resource recovery efficiency.
3Productivity
If traditional smelting processes are used, then copper recovery is achieved, but tin and lead end up as contaminants requiring additional treatment
Solution Approach 1:
The invention segments the feedstock processing to create a dedicated solder stream that captures tin and lead before they can contaminate the copper product. By separating the processing pathways, tin and lead are recovered as valuable solder product rather than being treated as contaminants requiring removal from copper.
Solution Approach 2:
The invention applies preliminary action by pre-separating tin and lead into a solder stream before the copper refining stage. This preliminary separation prevents tin and lead from becoming contaminants in the copper product, eliminating the need for additional contamination removal treatments while maximizing recovery of these valuable metals.
4Adaptability or versatility
If lower grade feedstocks are processed, then feedstock availability increases, but the amount of further treatment and purification required increases
Solution Approach 1:
The invention segments the processing of low-grade feedstocks into specialized copper and solder streams, each optimized for its target metals. This segmentation allows the process to accept a wide range of feedstock qualities while minimizing downstream refining requirements, as each stream receives tailored treatment that maximizes metal recovery and minimizes impurities.
Solution Approach 2:
The invention applies parameter changes by adjusting flux compositions, temperature profiles, and oxygen potential specifically for each stream based on feedstock quality. These parameter optimizations ensure that even low-grade feedstocks are processed efficiently, producing high-purity products with minimal downstream treatment required.
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 enhances the recovery of tin, lead, and copper, resulting in a higher purity solder product with reduced contaminants, minimizing further treatment needs and increasing the economic viability of downstream refining.
Implementation Method 1
partially reducing the first solder refining slag, thereby forming a first crude solder metal composition and a second solder refining slag
Implementation Method 2
Metals having a lower affinity for oxygen, if present in oxidized state readily reduce to their elemental metal form and move to the heavier and underlying metal phase
Data Source
AI summary
A process for the production of a crude solder composition includes the provision of a first solder refining slag that includes tin and/or lead. The process furtherincludes the steps of partially reducing the first solder refining slag, thereby forming a crude solder metal composition and a second solder refining slag, followed by separating the second solder refining slag from the crude solder metal composition,and partially reducing the second solder refining slag, thereby forming a second lead-tin based metal composition and a second spent slag followed by separating the second spent slag from the second lead-tin based metal compositionA copper containing fresh feed is added to step (ii), preferably before reducing the second solder refining slag.